2 SAFETY ASPECTS, PROCEDURES, TOOLS AND...

CONTENTS

2 SAFETY ASPECTS, PROCEDURES, TOOLS AND EQUIPMENT

2.1 Safety Precautions 1

2.2 Overhead Line Working 3

2.3 Clearances 6

2.4 Excavation Procedures 31

2.5 Rigging and Lifting 37

Section 2 I Page 1UK POWER NETWORKS OVERHEAD LINES CRAFT MANUAL I 2015

2.1 SAFETY PRECAUTIONS

2.1.1 General Provisions 1

2.1.2 Objections 1

2.1.3 Safety Equipment and Protective Clothing 1

2.1.4 Working at Height 1

2.1.4.1 Use of Ladders 1

2.1.4.2 Use of Scaffolding 2

2.1.4.3 Overhead Line Refurbishment 2

2.1.1 General ProvisionsAll work undertaken on distribution systems up to and including 132kV, together with associated plant and apparatus under the ownership or control of UK Power Networks, must be carried out in accordance with UK Power Networks Distribution Safety Rules.

Additionally all work will be carried out with due regard to the legislation and good working practices as described in Section 1 – Definitions, Legislation and Good Working Practices.

UK Power Networks has produced a safety booklet known as the HSS Handbook. This handbook will help keep you informed about general health and safety matters relating to your work. It is important that you are fully conversant with its contents and refer to it in conjunction with using this Craft Manual.

Additionally, a copy of the Company Safety Policy is available at every depot for all employees to inspect.

2.1.2 ObjectionsWhen any person receives instructions regarding the operation of, or work upon, UK Power Networks systems, and associated plant and apparatus, he/she must report any objections on safety grounds to the person issuing the instructions.

That person must then have the matter investigated and, if necessary, referred to a higher authority for a decision before proceeding.

2.1.3 Safety Equipment and Protective ClothingRefer to Section 12 of the HSS Handbook.

2.1.4 Working at HeightAll activities that involve working at height are covered in The Work at Height Regulations 2005.

All UK Power Networks procedures and equipment (and inspections) are dealt with in HSS 01 067 ‘Working at Height’. Also refer to Section 5 of the HSS Handbook.

2.1.4.1 Use of Ladders

Refer to HSS 01 118 which deals with the Safe Use and Inspection of Ladders and Stepladders.

Only approved ladders are to be used on wood pole overhead lines. They must be non-conducting and constructed of wood or fibreglass.

I Section 2 UK POWER NETWORKS OVERHEAD LINES CRAFT MANUAL I 2015

2.1.4.2 Use of Scaffolding

Scaffolding can be a purpose built structure or a temporary prefabricated tower assembled on site.

The use of scaffolding by UK Power Networks staff is detailed in HSS 01 112 ‘Safe Use of Prefabricated Low Level Access Equipment, Mobile Towers and Traditional Scaffolds’ and includes guidance for working on traditional scaffolds built by others. As scaffolding is only used on rare occasions, employees must be fully conversant with this document before starting any work involving any type of scaffold.

2.1.4.3 Overhead Line Refurbishment

Before starting the works, a point of work assessment must be carried out with due regard to the traffic conditions, public safety and access, and safety of staff on site, together with the length and duration of the work being undertaken.

Refer to HSS 01 068 ‘Working and Climbing on Wood Poles’ and Lattice PB Poles and Section 5 of the HSS Handbook.


2.2.1 Access to Pole-topThe normal methods of access to the pole-top will be as follows:

• Mobile Elevating Work Platforms (MEWP), either a cherry picker or hydraulic platform.

• Approved wood or fibreglass ladders, harness and pole choker (where applicable).

• Climbing irons, harness and pole choker (where applicable).

2.2.2 Climbing of Wood Poles

2.2.2.1 General Precautions

Details of the use, care, maintenance and inspection of all types of approved climbing equipment can be found in Section 5 of the HSS Handbook. DSR Section 3 covers the general safety precautions when climbing a Pole.

• Before any pole is climbed it Shall be tested in an Approved manner.

• No pole badly impaired by decay or damage or whose stability is in doubt Shall be climbed until it has been supported by Approved means.

• The pole Shall then either by climbed by only one person at a time or access to the top of such pole Shall be by Approved means independent of the pole.

• Ensure the pole being worked on is the correct pole.

• Do not climb a pole marked ‘D’ or a pole which is classified as unsafe. Failure to follow these instructions may result in the pole moving or falling and injury being sustained.

• Wood poles are chemically treated and protective gloves must be worn at all times whilst handling them. Barrier cream must be applied to exposed areas of skin.

• Test all wood poles in an approved manner before attempting to climb them.

• All persons gaining access to and during work on towers, poles and high structures Shall make proper use of Approved safety equipment and Shall be in visual range of another person. All persons concerned Shall be fully conversant with Approved rescue procedures.

• All persons concerned must be fully conversant with approved rescue procedures and a rescue kit must be at the ready at all times with the seal intact.

2.2 OVERHEAD LINE WORKING

2.2.1 Access to Pole-top 3

2.2.2 Climbing of Wood Poles 3

2.2.2.1 General Precautions 3

2.2.2.2 Considerations Before Working at Pole-top 4

2.2.2.3 Testing For Leakage Currents from Live Line Steelwork 4

2.2.3 Pole-top and MEWP Rescue Procedure 4

2.2.4 Work on Low Voltage Apparatus and Conductors 4


2.2.2.2 Considerations Before Working at Pole-top

In addition to the general precautions above, the following items need to be considered where applicable:

• Inspect one span either side for damaged conductors or fittings.

• Inspect stay wire and fittings for damage (if fitted).

• Decide how access is to be gained to the pole-top and, if necessary, remove the ACD.

• Visually inspect pole and pole-top fittings from ground level.

• Hammer test pole using approved methods.

• Visually inspect pole for external rot.

• Check climbing equipment.

• If ladders are being used, ensure they have a current tag/label.

• Check and inspect all lifting equipment, ensuring it is tagged and in date.

• Check rescue kit.

• Ensure all considerations are met for SSSIs, reservoirs, railways and chemical plants etc.

• Ensure weather conditions are suitable i.e. wind, lightning, icy pole etc.

• Ensure there is no danger to the public, livestock and traffic etc.

• Erect signing, lighting and guarding in line with NRSWA if needed.

• Ensure UK Power Networks vehicles are parked safely and correctly.

• Ensure the required safety documents are issued.

• Ensure all members of the team are aware of their responsibilities.

• Be aware of the effects of any other work being done on the line, or any other line in the vicinity.

2.2.2.3 Testing For Leakage Currents from Live Line Steelwork

Note: This section is applicable to HV poles only

• No person shall climb above 3.7m until the steelwork has been tested using an approved leakage instrument.

• The instrument is set up following the manufacturer’s instructions and a test is completed on the steelwork.

• If the instrument indicates there is no leakage, the pole can be climbed or worked upon above the 3.7m limit, but not exceeding the safe working clearance of the proximity limit marker. This shall be installed on the pole at a distance as per the UK Power Networks Distribution Safety Rules Section 4.4.1.

• If conductors are to be raised or lowered the requirements of the UK Power Networks Distribution Safety Rules Section 5.10.7 shall be followed.

• There is no longer a need to flash earth the steelwork.

Where it is impracticable to carry out work or testing without climbing above 3.7m a Senior Authorised Person shall only give permission for a person to climb above 3.7m. The person shall then climb under the personal supervision of an Authorised Person, whose duties include HV Switching.


2.2.3 Pole-top and MEWP Rescue ProcedureThe procedures for Pole and Mobile Elevating Work Platform Rescue Techniques are detailed in Section 5 of the HSS Handbook.

2.2.4 Work on Live Low Voltage Apparatus and ConductorsIn addition to the previous requirements, work on LV apparatus and conductors must be carried out in accordance with HSS 40 045 ‘Basic Requirements for Live Working on Low Voltage Apparatus’.

2.2.5 Operation of Overhead LV FusesSome modern LV fuse carriers are manufactured from glass re-inforced resin. The outer surface of the resin is covered with a gel glaze to protect it from the weather. This glaze wears away over time which often results in water soaking the resin thereby reducing the insulation level of the resin. When a fuse is removed from one of these fuse carriers , in damp conditions, a small amount of electricity can track short distances beneath the surface of the resin.

This means that we can no longer rely on these fuse carriers to provide a point of isolation. Whilst there is no chance of the leakage building up to produce a flashover, the leakage could cause a slight electric shock to someone touching the fuse unit or carrier without wearing LV approved gloves or working on a section of LV network isolated by this type of fuse unit that has not been shorted to the neutral.

The problem is not with any one manufacturer, but with all ‘plastic’ fuse carriers on poles that have been in service for some years and exposed to sunlight and moisture.

To reduce the chance of experiencing a slight shock, the following practices shall be used on LV work where the isolation is provided by these plastic fuse carriers:

• Low voltage cable jointing work must be carried out using live techniques at all times. Where this is not practicable then the work may only be carried out once the tails have been removed from the dead side of the pole mounted fuse cut-out.

• Work on open wire low voltage overhead lines under dead conditions must be carried out only when an Approved Earth/Short is in position between the point of work and the point of isolation.

• Work on ABC shall be done as if it is live, as there is no simple way of earthing the conductors.

These fuse carriers also leak a voltage to the surface of the resin so it is important that rubber gloves shall be worn:

• When inadvertent hand contact with these fuse units when live is a possibility.

• When working, or switching on these units if the LV system has not been proved to be dead and earthed.

• Finally, to reduce the risk of losing your grip and falling down the pole from receiving a ‘tingle’ from the fuse carrier, please ensure that you comply with Networks policy of being permanently attached whilst carrying out work and fusing at all pole mounted fuse units.


2.3 CLEARANCES

2.3.1 Introduction 7

2.3.2 Definitions of Types of Insulation 7

2.3.2.1 Bare 7

2.3.2.2 Lightly Insulated Conductors 7

2.3.2.3 Covered Conductors 7

2.3.2.4 Effectively Insulated Conductor 7

2.3.3 Clearances 8

2.3.3.1 Derivation of Clearances 8

2.3.3.2 Application of Clearances 8

2.3.4 Clearances for Bare and Lightly Insulated Conductors 8

2.3.4.1 Clearances to Ground and Roads 9

2.3.4.2 Clearances to Objects 10

2.3.5 Clearances for Effectively Insulated Conductors 11

2.3.5.1 Clearances to Roads 11

2.3.5.2 Clearances to Ground 12

2.3.5.3 Clearances to Buildings and Structure 12

2.3.5.4 Attachments to Buildings 12

2.3.6 Clearances Where Power Lines Cross or are in Close Proximity 13

2.3.7 Clearance to Railways and Associated Structures 14

2.3.8 Waterway Crossings 14

2.3.9 Clearances to Telecommunications Lines 15

2.3.9.1 Vertical and Lateral Clearances to Telecommunication Lines 15

2.3.9.2 Clearance of Apparatus when Poles are Jointly Used 16

2.3.10 Work in Proximity to Overhead Lines 16

2.3.11 Recreational and Vulnerable Sites 29

2.3.12 Vegetation Management and Tree Clearances 30

2.3.12.1 Introduction 30

2.3.12.2 Tree Clearance Work 30


2.3.1 Introduction

The Introduction of the Electricity Safety, Quality and Continuity (ESQC) Regulations 2002 has reaffirmed that the Department of Energy and Climate Change and the Health and Safety Executive consider ENA TS 43-8 ‘Overhead Line Clearances’ as the national standard for clearances and this should be used when considering clearances for both new and existing lines.

This section complies with ENATS 43-8 and provides guidance for all types of overhead conductors and ensures public safety and protection against contact with overhead lines.

The normal use of any land, buildings or structures crossed by the line can only be determined by local assessment and may require an increase in the clearances specified. All clearances must be determined by assessment of the individual site circumstances.

2.3.2 Definitions of Types of Insulation

2.3.2.1 Bare

A line with no insulation or inadequate insulation applied.

Conductors in this category are:

• No insulation covering (All Voltages).

• PBJ insulation covering (LV).

2.3.2.2 Lightly Insulated Conductors

A conductor that is insulated against momentary phase-to-phase or phase-to-earth contact, but must be considered as a bare conductor for all clearances purposes (including ground clearance.)

Conductors in this category are:

• PVC covering (EHV & HV).

• Single PVC covering (LV).

2.3.2.3 Covered Conductors

A conductor that offers greater protection against momentary phase-to-phase or phase-to-earth contact than lightly insulated conductors, and can be used to provide an additional level of protection. The clearance distances for covered conductor are to be the same as bare conductors.

The only conductor in this category is:

• Black XLPE covering (HV). (Trade name BLX)

2.3.2.4 Effectively Insulated Conductor

A line conductor which is insulated for continuous phase to phase or phase to earth contact and is protect, so far as reasonably practicable, against mechanical damage or interference having regard to its accessibility.

Note: This indicates that this type of conductor may be placed such that it is ordinarily accessible, providing that it is safe in the particluar circumstances.

HV conductors need to have an earthed metallic screen as well as sufficient mechanical protection to be classed as Effectively Insulated. UK Power Networks do not operate any HV or above conductor that is Effectively Insulated.

Conductors in this category include:

• PVC/PVC covered 22mm aluminium and 16mm copper LV conductor.

• PVC insulated and sheathed conductor.

• XLPE LV Aerial Bundled Conductor (ABC).


2.3.3 ClearancesClearances given in this document should be used as guidelines.

Where definitive clearances are required by a member of the public, a site survey should be carried out and any precautions which are deemed necessary should be formally recorded.

2.3.3.1 Derivation of Clearances

The clearances specified in this document have been derived from the summation of the following:

• Basic clearances as specified in ENA TS 43-8 ‘Overhead Line Clearances’.

• For particular applications, an additional ‘Application Factor’ has been added to the ENA TS 43-8 clearance distances. The reasons for this increase in distance are:

• Application Factor 0.3m – Applied in situations where there is little risk of direct human contact. It is an allowance for measurement inaccuracies.

• Application Factor 0.8m – Applied for clearances to normal ground, tracks and roads to allow for the increasing heights of farm machinery.

• Application Factor 1.2m – Applied for clearances where there is the risk of direct human contact. The clearance in ENA TS 43-8 only allows for a person moving their arm holding a short object. This clearance is allowing for the possibility of a longer object being used.

Not all clearances will be derived by the above methods since some must comply with Statutory Requirements.

2.3.3.2 Application of Clearances

The following additional factors should be taken into consideration when providing clearances to overhead lines:

• Allowances must be made for the effects of creep in conductors, as the specified clearance must be maintained for the life of the conductor. Short Term creep has been taken care of by introducing a pre-tension sag to conductors during erection. Long term creep is taken care of by erecting the conductors at a higher level than the minimum requirements and therefore the long term creep will still leave the conductors with the required clearances.

• Clearances to obstacles must be based on conductor at maximum operating temperature.

• In some cases, lines are operated at a lower voltage than that for which they are designed. It is important, when specifying clearances to fixed objects, that the clearances appropriate to the ultimate system voltage of the line are adopted.

• When an overhead line is erected in proximity to existing obstacles, the clearances should allow for future maintenance of the obstacle.

• When work is to be carried out, or obstacles are to be erected in proximity to an existing overhead line, the clearance may need to be increased substantially to allow for the operation and movement of site traffic.

2.3.4 Clearances for BARE and LIGHTLY Insulated ConductorsThe tables in this section give the clearance distances for each situation. An application factor has been applied to the regulatory distance to provide enhanced security from accidental contact.

For existing lines, built before the implementation of the ESQC regulations in 2003, that have not been substantially altered, the regulatory minimum clearance shall be in accordance with ENA TS 43-8. Lines built after the implementation of the ESQC regulations and substantially refurbished or altered lines must comply with the New/Substantially altered clearances.


2.3.4.1 Clearances to Ground and Roads

Table 1 sets out the minimum distance for ground clearance at the specified maximum operating conductor temperature, where conductor and insulator sets are hanging vertically or are deflected 45° from the vertical towards the object. (including services)

Table 1 – Determining Clearances to Ground and Road

Note:

1. Steelwork that is not connected to earth, must not be erected within 3m of the ground.

2. Overhead line jumpers shall be erected to prevent, in the case of a failure, any part of the jumper coming within 3m of the ground.

Description of Clearance Minimum Clearance (m) for Existing Lines

System Voltage kV

Minimum Clearance (m) for New/Substantially

Altered LinesSystem Voltage kV

Up to 33

66 132 Up to 33

66 132

Line conductor to ground (excluding roads) 5.2 6.0 6.7 6.0 6.8 7.5

Line conductor or cable/wire (other than line conductor) to road surface other than a high load route or dual carriageway

5.8 6.0 6.7 6.6 6.8 7.5

Line conductor or cable/wire (other than line conductor) to road surface of designated high load routes

6.9 7.1 7.5 7.2 7.4 7.8

Line conductor to road surface where ‘Skycradle’ can be used. (With adjacent circuits LIVE)Line conductor to road surface where ‘Skycradle’ can be used. (With adjacent circuits DEAD)

8.2

7.6

8.4

7.6

8.8

7.6

8.2

7.6

8.4

7.6

8.8

7.6

Line conductor to dual carriageway road surface where scaffolding is to be used on:(i) 3 lane (ii) 2 lane

14.011.0

14.211.2

14.611.6

14.011.0

14.211.2

14.611.6

Bare live metalwork e.g. transformer terminals, jumper connections etc. (These clearances apply to supports of overhead lines, which in addition support transformers, isolators, cable sealing ends etc.)

4.3 5.1 Controlled Zone

Safety Rules Apply

5.1 5.1 Controlled Zone

Safety Rules Apply


Table 2 – Determining Clearances to Objects

2.3.4.2 Clearances to Objects

Table 2 sets out the minimum distance to objects at the specified maximum operating conductor temperature, where the conductor and insulator sets are hanging vertically or are deflected 45° from the vertical towards the object.

Description of Clearance Minimum Clearance (m) For Existing LinesSystem Voltage kV

Minimum Clearance (m) For New/Substantially

Altered LinesSystem Voltage kV

LV 1 to 33 66 132 LV 1 to 33 66 132

Line conductor to any object which is normally accessible (including permanently mounted ladders, access platforms) or to any surface of a building. (Refer to note 1)

3 3 3.2 3.6 3 4.2 4.4 4.8

Line conductor to any object to which access is not required AND on which a person cannot stand or lean a ladder. (Applies to objects like vehicles, flag poles etc.) (Refer to note 2)

0.8 0.8 1 1.4 0.8 1.1 1.3 1.7

Line conductors to trees under/adjacent to line and:

(i) Unable to support ladder/climber

0.8 0.8 1 1.4 0.8 1.1 1.3 1.7

(ii) Capable of supporting ladder/climber 3 3 3.2 3.6 3 4.2 4.4 4.8

(iii) Trees falling towards line with line conductors hanging vertically only

0.8 0.8 1 1.4 0.8 1.1 1.3 1.7

Line conductor to trees in Orchards and Hop Gardens.These clearances must be obtained vertically when any part of a tree is within 8m of a line horizontally (Refer to note 4)

3 3 3.2 3.6 3 4.2 4.4 4.8

Line conductor to irrigators, slurry guns and high-pressure hoses (refer to note 5)

30 30 30 30 30 30 30 30

Line conductor to street lighting standards with:

(iv) Standard in normal upright position

1.7 1.7 1.9 2.3 1.7 2.9 3.1 3.5

(v) Standard falling towards line with line conductor hanging vertically only

1.7 1.7 1.9 2.3 1.7 2.9 3.1 3.5

(vi) Standard falling towards line (Refer to note 6)

0.4 0.4 0.7 0.8 0.4 0.7 1 1.1


Notes:

1. The regulatory minimum clearance allows for a person standing on, or against these structures, but only allows free movement of short-handed objects.

2. The height or position of the object should take into account any possible undulating or rocking movement of the object e.g. a mobile crane travelling over uneven ground.

3. Clearances quoted for line conductors to trees in Table 2, item (i) and (ii) are minimum acceptable clearances but, in practice, larger clearances will be necessary to take account of growth rates of trees, and of the swaying of trees/branches in the wind. Clearances quoted in (iii) are recommended in order to protect lines from falling trees but, due to wayleave considerations, will not always be attainable. Detailed guidance on the avoidance of danger from electric lines in forests is contained in ENA Engineering Recommendation G55/2.

4. These clearances shall be obtained vertically when any part of a tree is within 8m horizontally of a line. For hop gardens, the clearances apply to the strain wires forming the mesh supporting system.

5. The clearance quoted is for general guidance only. Detailed guidance on the use of irrigators, slurry guns and high-pressure hoses in the vicinity of overhead lines is contained in ENA Engineering Recommendation G45/1.

6. The clearances quoted in line conductors to street lighting standards assume that the maintenance platforms will be positioned such that clearances quoted are maintained.

The clearances quoted in item (vi) can be neglected if the location of the lighting standard is such that impact by a vehicle is improbable. ENA Engineering Recommendation G39 contains guidance on maintenance of street lighting standards in proximity to overhead lines. Where for maintenance purposes the operative requires to work on the upper part of the lantern, within the clearances specified in item (iv), appropriate safety measures shall be taken, which shall be agreed in advance between the distribution or transmission company and the lighting maintenance company or authority. The clearances quoted in item (v) include additional clearance to allow for the erection of street lighting standards.


2.3.5 Clearances for EFFECTIVELY Insulated Conductors

Effectively insulated conductors shall comply with the clearances in this section.

Clearances must be obtained with the conductor/earth wire at its specified maximum temperature and deflected by any angle up to 45°.

2.3.5.1 Clearances to Roads

2.3.5.2 Clearances to Ground

Clearances to roads shall comply with Table 3. Clearances in other locations are listed below.

These clearances DO apply to effectively insulated services.

Note:

1. Metalwork that is not connected to earthed, must not be erected within 3m of the ground.

2. Overhead jumpers shall be erected to prevent, in the case of a failure, any part of the jumper coming within 3m of the ground.

Item Description of Clearance Minimum Clearance (m)

1. Line conductor or cable/wire (other than line conductor) to road surface other than as specified in Item 2, 3 and 4

5.8

2. Line conductor or Cable/wire (other than line conductor) to road surface of designated high load routes

6.9

3. Line conductor road surface where ‘Skycradle’ can be used (with adjacent circuits live)Line conductor road surface where ‘Skycradle’ can be used (with adjacent circuits dead)

8.2

7.6

4. Line conductor to dual carriageway road surface where scaffolding is to be used on:(i) 3 lane(ii) 2 lane

14.011.0

Table 3 – Determining Clearances to Roads

Location Minimum Clearance (m)

Where machinery operate beneath or around the line 6.0

Along the line of hedgerows, fences and boundary walls etc. 4.0

Domestic driveways with an access width of 2.5m or less, which is defined by gatepost, hedges or other fixed features

4.3

Between buildings where there is no vehicular access 3.5

To ground where none of the above apply (and excluding roads) 3.5

Table 4 – Clearances to Ground


2.3.5.3 Clearances to Buildings and Structure

The clearances in Table 5 DO NOT apply to mains and services attached to buildings.

2.3.5.4 Attachments to Buildings

For conductors attached to buildings it is necessary to ensure that the attachment route avoids risk of abrasion.

2.3.6 Clearances where Power Lines Cross or are in Close ProximityWhere conductors of different operating voltage cross over or are in close proximity to one another, the conductor carrying the higher voltage will be placed above the lower voltage conductor in all circumstances. The following clearances apply to all types of conductor.

Note:

One of the following methods of determining clearances must be adopted:

1. With the upper conductors/earth wire hanging vertically and the lower conductors/earth wire deflected at 45° under the following conditions:

• Upper conductor at its specified maximum temperature coincident with lower conductor, at an assumed temperature of 25°C less than its specified maximum temperature.

• Lower conductor at a temperature of -5.6°C (no ice) coincident with upper conductor at an assumed temperature of 20°C.

or alternatively:

2. With the upper conductor/earth wire hanging vertically at its specified maximum temperature and the lower conductor/earth wire deflected at any angle up to 45° at a temperature of -5.6°C (no ice). In localities where there is a likelihood of conductor icing, it may be appropriate to consider the effects of such icing.

Item Description of Clearance Minimum Clearance (m) For Existing LinesSystem Voltage kV

0.4 1 to 11 33 66 132

1. Lowest line conductor or earth wire of upper line to highest line conductor of lower line (Note 1)

1.2 1.8 2.0 2.3 2.7

2. Lowest line conductor or earth wire of upper line to earth wire over lower line where erected (Note 1)

0.7 1.4 1.6 2.3 2.7

3. Lowest line conductor or earth wire of upper line to any point on a support of the lower line on which a person may stand (Note 2)

4.0 4.2 4.2 4.4 4.8

4. Support of upper line and any conductor of lower line (Note 2) 7.5 7.5 7.5 7.5 15.0

Table 6 – Clearances of Crossing or Close Power Lines

Location Minimum Clearance (m)

Vertical clearance to any surface or structure that is accessible without access equipment (refer to Figure 5)

3.0

Horizontal distance to any surface of a building or structure which is accessible (refer to Figure 5)

1.0

Clearance to parts of a building or structure not normally accessible (Care has to be taken to ensure that the conductor will not abrade against the building) (refer to Figure 5)

0.5

Clearance to free-standing apparatus such as street lighting columns, traffic signs, British Telecom poles or columns (refer to Figure 5)

0.3

Table 5 – Clearances to Building and Structure


Clearances must be obtained with the conductor/earth wire at its specified maximum temperature and deflected by any angle up to 45°.

Item Description of Clearance Minimum Clearance (m) For Existing LinesSystem Voltage kV

0.4 1 to 33 66 132

1. Ground level 6.1 6.1 6.1 6.7

2. Ground level at roads or yards where road mobile cranes are likely to be employed

10.7 10.7 10.7 11.5

3. Rail Level (Note 1) 7.3 7.3 7.3 8.0

4. Buildings, gantries or other structures on which a person might stand and to traction wires

3.0 3.0 3.0 3.7

Vertical Clearance from Bank Top Horizontal Clearance from Bank Top *

Voltage Statutory Recommended Recommended

415V 5.2m 6.0m 9.0m

6.6KV 5.2m 9.0m 10.0m

11KV 5.2m 9.0m 10.0m

33KV 5.2m 9.0m 10.0m

132KV 6.7m 12.0m 15.0m

* Horizontal clearance of any tower or support from the top of the bank of the watercourse

Table 7 – Clearances to Railways and Associated Structures

Table 8 – Waterway Crossing

2.3.7 Clearance to Railways and Associated Structures

The following clearances apply to all types of conductor.

Note 1:

The clearance specified in Item 3 and Item 4 does not incorporate any allowances for the use of scaffolding or Skycradle across the railway tracks/traction wire erection/maintenance of overhead lines. Additional clearance of 2.5m and 4.9m are required between scaffold net or Skycradle boom and traction wires and rail respectively.

2.3.8 Waterway CrossingsThere is no national agreement which applies to clearance above waterways. The clearances are dealt with by an individual agreement with the Wayleaves office. The minimum distance that is applied shall be equal to the statutory distance and measured from the top of riverbanks and flood banks.

When overhead lines are substantially altered, clearances will increase to the Environment Agency recommended distances to ensure that overhead lines do not inhibit or prevent the future machine maintenance of a watercourse.

Table 8 below sets out the statutory minimum distance and the Environment Agency recommended distances.

Agreements for lines up to and including 33kV should include the proviso that the line can be made DEAD for short mutually agreed periods. This could be for a few hours or several days depending on the importance of the line in the system, and other outages. Outages are unlikely to be obtained for lines of 132kV, except with very long notice.


2.3.9 Clearances to Telecommunications Lines

2.3.9.1 Vertical and Lateral Clearances to Telecommunication Lines

This document gives a summary of the clearance requirements to telecoms lines. Detailed information is set out in ENA Engineering Recommendation PO5.

Proximities of High Voltage Power Lines and Telecommunication Lines

1. For overhead lines, where there is insufficient insulation to give protection, the horizontal separating distance between the power line and any part of a telecommunication line shall be not less than the height of the power line or any exposed power conductors (measured at the nearest support), or 1½ times the height of the telecommunication line, whichever is the greater, provided that where the lines are erected on ground at different levels, the heights shall be calculated from the lower ground level (refer to Figure 6).

2. In cases of difficulty, a reduced separating distance from that specified in Step 1 may be permitted if jointly agreed by the local managers of Telecommunications Line Operator and UK Power Networks . The reduced distance shall be no less than that shown in Figure 7.

3. Where UK Power Networks power lines and Telecommunication lines approach but do not cross, the horizontal separating distance specified in Step1 may be reduced to not less than 3.5m (refer to Figure 9), provided that the voltage does not exceed 33kV, and either the Telecomminications line or the power line are sufficiently insulated or covered for the voltage used. Any span where the clearance is reduced shall be insulated or covered throughout its length.

Proximities of Low Voltage Power Lines and Telecommication Lines

1. Where Telecommunication or DNO conductors are bare, clearances shall be 1200mm to non-earthed phase conductors, and 900mm to earthed conductors.

2. Where BOTH the Telecommunication and DNO conductor lines are sufficiently insulated or covered, clearances may be reduced to:

• Telecommunication line to un-earthed conductor or ABC bundle 900mm.

• Telecommunication line to earthed conductor or concentric neutral service cable 600mm.

3. Where Telecommunication lines and DNO conductors are attached to a building, the Telecommunication lines shall be lowermost.

4. There shall be a minimum vertical separation of 900mm between the uppermost Telecommunication line and the lowermost non-earthed power line, or 550mm to an earthed power line (refer to Figure 11). Apart from this there shall be no Telecommunication plant in the shaded area.

Crossing of High Voltage Power Lines and Telecommunication Lines

1. Where the voltage of the power line exceeds 33kV the Telecommunication line shall be placed underground. For power lines operating at a nominal system voltage of 132kV and above, supported on steel towers, the Telecommunication terminal poles and stays shall have a minimum horizontal clearance of 15m to the outer conductors of the power line, hanging vertically in still air. For other power lines operating at voltages above 33kV, distances outlined in Item 1 – Proximities of High Voltage power lines and Telecommunication lines apply.

2. The separating distance between the lowermost power conductor and the uppermost Telecommunication insulated wire, or insulated aerial cable shall be not less than 1.8m at the likely maximum temperature of the power conductors, whether or not in use.


3. The separating distance between the lowermost power conductor and the nearest Telecommunication pole, when viewed in plan, shall be not less than 1.8m. Alternatively, the vertical separating distance between the lowermost power conductor and the top of the Telecommunication pole shall be not less than 2.75m at the likely maximum temperature of the power conductors, whether or not in use. (This may be reduced to 1.8m if the power cables are insulated or covered. Refer to Figure 8.)

4. It is preferable, although not essential, that the actual point of crossing is near a power line support, provided that the shortest distance between any such support and the Telecommunication line is not less than 1.2m (refer to Figure 8).

Crossing of High Voltage Aerial (Power and Pilot) Cable CrossingsThe separating distances shall be as follows:

1. Between an aerial power cable and the uppermost Telecommunication line: not less than 1.2m at the likely maximum temperature of the power cable, whether or not in use.

2. Between an aerial pilot cable and the uppermost Telecommunication line: not less than 0.90m at the likely maximum temperature, whether or not in use.

Crossing of Low Voltage Power Lines and Telecommunication Lines

1. The Telecommunication line may be above or below the power line.

2. Where Telecommunication lines and UK Power Networks lines cross, there shall be a clearance of at least 900mm between a Telecommunication line and any non-earthed power line, and a clearance of at least 600mm between any part of any Telecommunication line and the remainder of the overhead power line and associated plant (refer to Figure 10), where one of the parties are effectively insulated.

3. At crossings where, in the opinion of Telecommunication Line Operators, the supports or the two lines are in positions such that at the actual point of crossing there will be no appreciable decrease in the clearance with changes in temperature or under the worst conditions of ice loading, a vertical clearance of not less than 600mm will be allowed between the Telecommunication line and any part of the overhead power line. (Note: This will normally occur where a power line support and a Telecommunication pole are both little more than 1.2m from the point of crossing).

2.3.9.2 Clearance of Apparatus when Poles are Jointly Used

Engineering Recommendation EB/TP3 Issue 3 – Conditions for Telecommunication Line Operators and Public Suppliers’ Joint Use of Poles specifies the clearance requirements for apparatus when poles are jointly used.


Figure 1 – Clearance to Objects on Which a Person Can Stand


Figure 2a – Clearance to Trees

Figure 2b – Clearance to Trees in Orchards

2


Figure 3 – HV Conductor Clearance to Lighting Columns


Figure 4 – LV Conductor Clearance from Lighting Columns

1.7m minimum

1.0m minimum

0.3m minimum

Conductors located in this zone shall be

effectively insulated

within 1.5m each side of a

column


effectively insulated along the entire span (pole to pole)

1.7m minimum

1.0m minimum

1.0m minimum

0.3m minimum

Nearest LV pole 1.7m min


effectively insulated along the entire span (pole to pole)

Conductors located in this zone shall be effectively insulated

within 1.5m each side of a column

0.3m minimum

1.0m minimum

1.7m minimum


Figure 5 – Clearance Between Structures and Effectively Insulated Conductors Installed on Poles (when not attached to buildings)

No ABC Within this Line. This Clearance Shall be Reduced to 500mm along blank walls.

3000

mm

Ground Clearance in Accordance with Section 2 of this Manual.

A

1000

mm

500mm500mm

A

1000

mm


Figure 6 – Minimum Separating Distance Between Telecom Line and HV Power Line Where There is Insufficient Insulation to Give Protection

H

h

X Minimum

Power Pole not Stayed

X Minimum

Stay with Insulator

X Minimum = 1.5h, or (H and D) Whichever is the Greater

H h

X Minimum

BT Pole not Stayed

X Minimum

Stay with Insulator

X Minimum = 1.5(h+d) or H, Whichever is the Greater

X Minimum

Stay without Insulator

D

d


Figure 6 continued

H

h

X Minimum


X Minimum

Stay with Insulator

X Minimum = 1.5h, or (H and D) Whichever is the Greater

H h

X Minimum

X Minimum

Stay with Insulator

X Minimum = 1.5(h+d) or H, Whichever is the Greater

X Minimum

Stay without Insulator

D

d

Telecoms Pole not Stayed


Figure 7 – Reduced Separation of Telecom and HV Overhead Lines

3.5m Minimum 2m Minimum

In this example it is assumed that the pole overturns where it enters the ground.

3.5m Minimum2m Minimum

In this example it is assumed that the pole overturns at its base.

2m Maximum


Figure 8 – HV Crossing Proximities

Lowest Power Conductor

1.8m

BT Pole

1.8m or 2.75mIf Power line is Un-insulated

BT Pole

Power Conductors

BT Conductor

UK Power Networks Pole

1.2m

1.8m

UK Power Networks Pole


Figure 9 – Minimum Separation Where Either Telecom Line or HV Overhead Line are Effectively Insulated

h

X Minimum


X Minimum

Stay with Insulator

X Minimum = 3.5m When Viewed from Above

X Minimum

BT Pole not Stayed

X Minimum

BT Stay with Insulator

X Minimum

BT Stay without Insulator

X Minimum = 3.5m When Viewed from Above


Figure 10 – Low Voltage Crossings and Proximities

900mm

900mm

600mm

900mm900mm

900mm

900mm

600mm

600mm

Non Earthed Power Conductor

Permanently Earthed Power Conductor

No BT Plant within this Zone

Note: Where BT or UK Power Networks conductors are bare, clearances shall be increased to 1200mm to non earthed (phase) conductors and 900mm to earthed conductors.


Figure 11 – Lines Attached to Buildings

1200mm Radius

Non Earthed Power Conductor

Permanently Earthed Power Conductor

550mm Minimum

No BT attachment within this zone apart from items attached 550mm below earth conductor or 900mm below non earthed power conductors.


2.3.10 Work in Proximity to Overhead LinesGuidance for the avoidance of danger from overhead lines can be found in Health and Safety Guidance document GS6.

2.3.11 Recreational and Vulnerable Sites

Overhead line supports in the vicinity of recreational sites are particularly vulnerable to unauthorised climbing.

There is also the risk of accidental contact with the line conductors by, for example, hang gliders, yacht masts, fishing lines and the control lines of kites or model aircraft. It is important that these sites are identified and the risk minimised.

It is impossible to define every situation where an overhead line support may be vulnerable to unauthorised climbing or the line subject to accidental contact. It must be remembered that a recreational site may be a designated area or an informal area which lends itself to recreational activities.

The following list gives the situations where the probable risk of danger is greatest (but it must be stressed that local knowledge is essential for the compilation of a complete list of vulnerable supports):

• Children’s play areas, both formal and informal (e.g. waste ground where there is evidence that children play regularly).

• Footpaths used by children on the way to or from school.

• Parks and sports grounds.

• Campsites and caravan parks (excluding sites used for residential mobile homes only).

• Chalet type developments where occupancy is for short periods (e.g. holiday lettings).

• Gypsy (Travellers) encampments.

• Recognised sailing waters, boat launching, mooring and parking areas.

• Fishing areas/pleasure beaches (including sand dunes).

• Designated picnic areas.

• Gliding and hang-gliding areas used by a club or company.

• For existing and new lines, negotiations will be opened with the site operator/owner with due regard to the severity of the hazard and remedial action.

• The following additional safety measures are offered as suggestions only. Each site must be individually assessed to determine the precise measures required.

• Display additional warning notices at appropriate sites.

• The National Federation of Anglers have issued a document ‘Advice to Clubs on Overhead Electric Power Lines’ which suggests that warning notices should be erected along the banks of fishing waters at a distance of 30m from an overhead line. Such notices are to be erected by angling clubs, not UK Power Networks, although a recommended design for the notices is available from the Safety Group.

• Erect additional anti-climbing guards.

• Install fully insulated conductors on LV lines.

• Reposition the line away from the vulnerable area. Note: Re-routing a line along the perimeter of a recreational site may not necessarily remove the hazard.

• In extreme situations, install an underground cable circuit.


2.3.12 Vegetation Management and Tree Clearances

2.3.12.1 Introduction

Vegetation – particularly trees – can provide good climbing aids when somebody attempts to scale poles or other equipment.

In addition, vegetation can affect the integrity of the overhead network and the reliability of the electricity distribution system.

UK Power Networks has an Engineering document EOP 01 0009 ‘Vegetation Management in the Vicinity of Overhead Lines and Structures’. It details our approach to this matter and ensures we comply with the relevant regulations.

It is essential that all new lines, diversions and alterations comply with these clearances.

Details of the basic clearances and specific sites/conditions can be found in Section 10 – Maintenance Tasks. They are the minimum that must be maintained at all times so, when cutting takes place, it is important to estimate the growth rate of the vegetation to the next cutting cycle.

2.3.12.2 Tree Clearance Work

All staff employed on Vegetation Management work must be trained in the relevant activities they perform and hold the relevant competencies and current certificates.

UK Power Networks have contracts in place, with one or more companies, to carry out all its vegetation management work, especially in the vicinity of, or for the erection of, overhead lines.

This is because of the strict legislation in respect of use of chainsaws and other machinery, together with the skills required for tree climbing and clearance.

Anyone who uses a chainsaw for work must:

• Hold a NPTC certificate and have received adequate training in safe use (Provision and Use of Work Equipment Regulations 1992).

• Wear suitable protective clothing (Personal Protective Equipment at Work Regulations 1992).

• Ensure that they have taken all reasonably practical steps so that no one is put at risk by their work (Health and Safety at Work Act 1974).


2.4.1 General RequirementsThe following points need to be considered prior to any form of excavation (mechanical or by hand):

• Ensure that the proposed excavation has been marked out.

• Consult mains records and other drawings for locations of any underground service.

• Mark recorded position of all known pipes and cables using approved module.

• Survey area with cable locator and re-mark positions.

• Obtain local knowledge of site.

• Revise marking out if necessary.

• Consult Work Instruction. Ensure that there is no possibility of contamination.

2.4 EXCAVATION PROCEDURES

2.4.1 General Requirements 31

2.4.2 Location of All Underground Services on Site 32

2.4.2.1 Planning and Preparation 32

2.4.2.2 Marking Location of Buried Plant and Equipment 32

2.4.2.3 Location of Underground Cables and Services 32

2.4.3 Trial Holes 33

2.4.4 Possible Soil Behaviour and Use of Shuttering 33

2.4.4.1 Soil Behaviour After Exposure to Excavations 33

2.4.4.2 Causes of Trench/Excavation Collapse 33

2.4.4.3 Shuttering of Excavations 34

2.4.4.4 Alternative to Shuttering 34

2.4.4.5 Care of Excavated Material 35

2.4.5 Working with Excavations 35

2.4.6 Mechanical Excavation 36

2.4.6.1 Mechanical Excavators 36

2.4.6.2 Mechanical Augers 36


2.4.2 Location of All Underground Services on Site

2.4.2.1 Planning and Preparation

• Buried utilities represent a major hazard to construction workers. Poorly planned excavations can cause cable or pipe damage resulting in costly repairs, delays and personal injury.

• It is important to know the location of all underground utilities in the working area before any excavation work is carried out.

• Consult all available plans (UK Power Networks records and those received from other utilities) and check the types of service present in the area of the worksite.

• If plans are not available of the worksite area, use local knowledge (e.g. consult land owner and ask about the presence of underground services).

• Check for land marks that indicate the presence of underground services (e.g. man-hole covers, hydrants, streetlights etc).

2.4.2.2 Marking Location of Buried Plant and Equipment

• Once any buried plant or equipment has been identified, it is important to mark its location with spray paints in respect to the working site.

• Do not use steel pegs to mark out the position of a service (they can damage the service).

2.4.2.3 Location of Underground Cables and Services

Refer to Figure 12 – Location of Underground Services.

• Use appropriate approved locating/avoidance devices to locate the service.

• The most common location device in use is the CAT (Cable Avoidance Tool). Before using this tool (or similar) it is important that you are fully familiar with the operating instructions and procedures.

• The CAT can also be used to ascertain the depth of buried equipment.

• A signal generator, known as a ‘Genny’ can be used in conjunction with the CAT to apply a distinctive signal that the CAT can detect. The ‘Genny’ can either be connected to a metallic service or used to induce a signal.

Cable Avoidance Tool

Cable

Detecting

LOCATION OF UNDERGROUNDSERVICES

G/L

Figure 12 – Location of Underground Services


2.4.3 Trial Holes• Once buried plant and equipment has been identified, dig trial holes to positively locate

services that might affect the work being undertaken.

• In the absence of any other information, and with the suspicion that buried plant may exist, carefully hand dig trial holes in the work area to identify its location.

• Note: A service has not been positively located until it has been physically uncovered (plans can be inaccurate or out-of-date).

2.4.4 Possible Soil Behaviour and Use of Shuttering

2.4.4.1 Soil Behaviour After Exposure to Excavations

When the ground consists of different layers (or strata), as shown in Figure 13, water can travel down the bedding planes, causing collapse of one or more upper layers into the trench.

Safe Side Sub Soil

Clay

Unsafe Side

2.4.4.2 Causes of Trench/Excavation Collapse

Excavations can collapse due to a variety of reasons, typically:

• Soil is unable to support its own weight without collapsing.

• The weight of loads placed near the edge of an excavation.

• Heavy loads striking the edge of an excavation.

• Variations in the nature of ground, such as pockets of sand or gravel.

• Excavating on or near the line of a previous excavation.

• Breakdown of the strength of soil by varying weather conditions.

• Vibration from traffic, plant and equipment.

• Failure due to bad workmanship.

Figure 13 – Soil Behaviour in Strata


2.4.4.3 Shuttering of Excavations

• If any personnel need to enter the hole, then shuttering may be necessary. Where shuttering is required, approved procedures must be used.

• Do not enter an excavation deeper than 1.2m unless adequate shuttering is in place.

• If the excavation is deeper than 1.2m, but is not to be entered by personnel, then no shuttering is required.

• If existing conditions could make the collapse of a hole more likely, and death or injury could occur as a result, then the hole shall be shuttered (even though it is less than 1.2m deep).

• An alternative shall be considered if shuttering is not possible or is impracticable.

• Some examples of conditions that might make collapse of part of a hole more likely are:

• The hole is to be dug against a wall.

• The nature of the ground is unstable (e.g. the ground is wet).

• An unstable mound of displaced earth builds up as digging proceeds.

• If possible, spoil shall be placed more than 0.5m from the side of the hole. If spoil is within 0.5m of the side of the hole, the height of the spoil heap shall be included when measuring the depth of the hole.

2.4.4.4 Alternative to Shuttering

In some instances, shuttering is not always the most practical solution to making an excavation safe. Refer to Figure 14 which shows an alternative solution to excavating in soft clay.

1. Slip in Soft Clay Spoil

Slipped Spoil

Spoil Moved Back

Surpace of Sliding

Slopes Cut Back

Poling Boards

3. Remedy by Close Timbering

2. Remedy by Cutting Back Slopes

Figure 14 – Alternative Solution To Excavating In Soft Clay


2.4.4.5 Care of Excavated Material

When excavated material bulk (spoil) is piled onto a horizontal surface, a cone shaped heap will be formed.

The internal angle between the surface of the pile and the horizontal surface is known as the angle of repose. It is related to the density, surface area and shapes of the material particles and their coefficient of friction.

Material with a low angle of repose forms flatter piles than material with a high angle of repose. In other words, the angle of repose is the angle a pile forms with the ground.

Figure 15 shows typical angles of repose for various materials. Note: All angles are from the horizontal.

Moist Earth (50")

Wet Clay (16")

Wet Sand (22")

Gravel with Sand (25")

Dry Earth (28")

Dry Sand (33")

Shingle (39")

Gravel (40")

Drained Clay or Rubble (45")

2.4.5 Working with Excavations

• Excavators and/or hand-held power tools must not be used within 0.5m of an electricity cable or gas pipe, unless the line of the cable has been identified by plans and positively confirmed by digging trial holes to verify location.

• Hand-held power tools must not be used directly over the marked line of a cable unless:

• The cable has been located at the position by careful hand digging and is 300mm (minimum) below the bottom of the surface to be broken.

• Physical means have been used to prevent the tool from striking the cable.

• Where it is necessary to break away or disturb concrete in which a cable is embedded, the cable must be made DEAD or another approved method used.

• Exposed cables must not be used as hand-holds or foot-holds by anyone climbing in or out of the hole.

• Any cable exposed for more than 1m across an excavation must be supported.

Figure 15 – Typical Angles of Repose


2.4.6 Mechanical Excavation• If overhead live lines are present in the vicinity of the excavation, all work shall be carried

out in accordance with live line instructions ‘General Working Rules’ and UK Power Networks Distribution Safety Rules.

• Any person driving/operating a mechanical excavator/auger must be trained and authorised to UK Power Networks recognised standards, and the equipment shall always be used in accordance with these standards. The person in charge of the work party is to instruct the excavator/auger operator, but the operator is in charge of the excavator at all times, and is the only person allowed in/on the machine.

2.4.6.1 Mechanical Excavators

• Before excavation, ensure all personnel are outside the back-arm radius of the excavator.

• Before leaving the excavator, ensure the hydraulically operated parts of the excavator (i.e. the feet, front bucket and jib) are on the ground. This is to prevent death or serious injury to personnel or damage to equipment caused by hydraulic or mechanical failure.

2.4.6.2 Mechanical Augers

• Before starting work it is essential that you know if there are any underground services in the area that you intend to excavate. Dangerous voltages, gasses and high pressures may be present and failure to follow the correct procedures could result in serious injury.

• Rotating parts and hydraulic pressures exist in the hydraulic drive motor. Ensure that the hydraulic drive motor is switched off and all hydraulic pressure is released before connecting the drive coupling. Failure to do this could result in serious injury.

As in all activities, the Health & Safety at Work Act gives workers the right to object to carrying out work if they feel that the work cannot be undertaken safely.


2.5 RIGGING AND LIFTING

2.5.1 Definitions 38

2.5.2 Lifting and Pulling Equipment 39

2.5.2.1 Lifting Applications 39

2.5.2.2 Pulling Applications 39

2.5.2.3 Inspection of Lifting and Pulling Equipment 39

2.5.3 Estimating the Load to be Erected 40

2.5.4 Ropes 41

2.5.4.1 Maintenance and Care of Ropes 41

2.5.4.2 Safe Working Load of Ropes 44

2.5.5 Ground Anchors 44

2.5.5.1 General 44

2.5.5.2 Safe Use 45

2.5.6 Knots 46

2.5.6.1 General 46

2.5.6.2 To Join Two Lengths of Rope 46

2.5.6.3 Hitches to Pull or Lift Poles or Spars 47

2.5.6.4 Loops and Harnesses 48

2.5.7 Tirfor 48

2.5.7.1 General 48

2.5.7.2 Setting up Tirfor 50

2.5.7.3 Tips When Using a Tirfor 52

2.5.7.4 Maintenance and Storage 53

2.5.8 Lever Lift Blocks 53

2.5.8.1 Pul-lifts 53

2.5.8.2 Ratchet Lever Hoist (Lug-all) 55

2.5.9 Single/Multi-sheave Blocks and Pulleys 56

2.5.9.1 Definitions of Blocks and Pulleys 56

2.5.9.2 Rope Blocks (single or combined single/multi-sheave blocks) 57

2.5.10 Slings 57

2.5.10.1 Definition 57

2.5.10.2 Safe Working Loads 59

2.5.10.3 Slinging Safety 59



2.5.11 Shackles 62

2.5.11.1 Definition 62

2.5.11.2 Safe Working Loads 63

2.5.11.3 Safe Use of Shackles 63


2.5.12 Winching 64

2.5.12.1 Safety when Winching 64

2.5.12.2 Precautions when Winching 65

2.5.12.3 Wire Winch Ropes 65

5.5.12.4 Paracore Rope Winch Ropes 65

2.5.13 General Precautions when Using Lifting Equipment 66

2.5.1 DefinitionsThe following definitions are commonly used in respect of lifting equipment:

Competent Person: Person who carries out the examination testing and certification of equipment, either before use, at six monthly intervals or after repair.

Factor of Safety (FoS): Ratio between SWL and MFL.

In Service Inspection: Inspection carried out by a responsible person before on site use of equipment.

Lifting Appliance: Any item of equipment used in lifting applications which is capable of providing movement of the load.

Lifting Equipment: Generic term to encompass all lifting gear and appliances

Lifting Gear: Any item of equipment used in lifting applications which is not physically capable of providing movement of the load.

Minimum Failing Load (MFL): Load under which the equipment will not fail in service.

Operative: Person who uses lifting equipment, having received suitable training.

Proof Load: Load applied before issue of Test Certificate. Usually one and a half times the SWL.

Responsible Person: Person who has sufficient knowledge and training to enable them to carry out ‘in service inspection of lifting equipment’.

Safe Working Load (SWL): Maximum load that can be applied to a piece of equipment as assessed by a Competent Person under certain service conditions.

Single Purpose Equipment: Equipment designed to be used for a specific application to lift a load in a certain manner (e.g. transformer lifting gin).

Statement of Conformity: Issued by manufacturer to confirm that certain tests have been carried out. Has the same status as a Test Certificate.

Test Certificates: Certificate issued by a Competent Person after Proof Loading of equipment. Must be retained for inspection.

Working Load Limit: Maximum load that may be applied to a piece of equipment in ideal conditions.


2.5.2 Lifting and Pulling EquipmentWhere applicable, all lifting equipment in use by UK Power Networks is subject to the conditions of Lifting Operations & Lifting Equipment Regulations 1998 (LOLER).

Some equipment has different SWLs depending on whether it is being used for pulling or lifting. This is because a different Factor of Safety is applied dependant on the activity being undertaken.

Examples of equipment that can be used as either pulling or lifting devices are pul-lifts and tirfors.

It is therefore important that the type of application is clear and a suitably rated item of equipment used.

2.5.2.1 Lifting Applications

A lifting application is defined as ‘any application where, in the event of the appliance or any of its associated equipment failing, the load does NOT BECOME STATIONARY’.

2.5.2.2 Pulling Applications

A pulling application is defined as ‘any application where, in the event of the appliance or any of its associated equipment failing, the load BECOMES STATIONARY’.

Thus, if for example a load were being ‘pulled’ up an incline on wheels, it would be regarded as a lifting application, as in the event of a failure the load would descend the incline under gravity.

2.5.2.3 Inspection of Lifting and Pulling Equipment

Only approved devices are to be used that have been regularly tested and have the SWL clearly marked.

Reference should be made to HSS 01 080 ‘Planning and Competency Requirements for Lifting Operations’.

New Equipment

Before lifting equipment is used or put into service for the first time:

• It must be thoroughly examined by a competent person.

• It must be marked with a unique equipment number and have a UK Power Networks identification tag fitted.

• It must be marked with its SWL.

• It must be marked with the Date of Test and the Next Test Date.

All equipment must be entered onto the tools and equipment database and a scheme of maintenance assigned.

Regular Inspection

• All items of lifting equipment undergo a regular thorough examination and inspection, details of which are recorded on the tools and equipment database. In general, the inspections are carried out every six months.

• Lifting equipment that has been satisfactorily thoroughly examined and a test certificate issued must be marked with its SWL, and the Company’s identification tag.

• A range of SWLs might be specified for the same equipment when used in different configurations (this information is kept with the equipment to which it relates, if it is not physically marked on it).


2.5.3 Estimating the Load to be ErectedBefore any lift of any kind is attempted, an estimation of the weight of the load must be made. Equipment suitable for the lift with sufficient SWL can then be selected.

In some cases (e.g. a transformer, recloser etc.), the weight is given on the actual item to be lifted, usually on the maker’s nameplate. Manufacturer’s literature can also be an invaluable guide to the weight of a load.

When erecting conductors, reference must be made to the erection tension/sag charts in the Overhead Line Construction Manual. The tables incorporate the over-tensioning required above design tensions to allow for conductor creep experienced after erection due to settlement.

The following tables give typical loading for equipment, poles and conductors. THEY ARE NOT TO BE USED AS ERECTION DATA.

Plant Item Average Weight of Average Unit

Auto Recloser/Sectionaliser 280kg

Balancer 250kg

LV Voltage Regulator 300kg

50kVA Transformer 550kg



Table 9 – Typical Loading for Equipment, Poles and Conductors

Length ofPole Metres

Light Medium Stout Extra Stout

Cubic Metres

Weight Kg Cubic Metres



Weight Kg

9.0 0.225 163 0.315 229 0.463 335 0.525 394

10.0 0.270 198 0.360 259 0.550 395 0.160 454

11.0 0.320 234 0.430 310 0.653 472 0.689 517

12.0 0.392 284 0.490 356 0.743 539 0.793 595

13.0 0.437 315 0.576 417 0.828 599 0.934 701

14.0 n/a n/a 0.643 467 0.949 686 1.057 793

15.0 n/a n/a 0.765 554 1.057 762 1.188 891

16.0 n/a n/a 0.869 630 1.174 848 1.348 1011

17.0 n/a n/a 0.995 721 1.317 950 1.498 1124

18.0 n/a n/a 1.148 828 1.536 1110 1.658 1244

19.0 n/a n/a 1.263 912 1.694 1225 1.819 1364

20.0 n/a n/a 1.379 996 1.852 1340 1.980 1485

21.0 n/a n/a 1.460 996 2.001 1445 2.141 1605

22.0 n/a n/a 1.540 1053 2.149 1550 2.302 1727

23.0 n/a n/a n/a n/a 2.202 1590 2.530 1897

24.0 n/a n/a n/a n/a 2.254 1630 2.758 2069

These are the weights of poles of minimum dimensions. Actual weight may be as high as the next class of pole.


It must be noted that these conductor tensions increase considerably when dead-ends etc. are being fitted.

2.5.4 Ropes

2.5.4.1 Maintenance and Care of Ropes

General Requirements

• Ropes must be stored in a suitable dry storage area.

• When not in use, ropes will be coiled and hung up.

• Before using any rope, an in-service inspection must be carried out.

• Defective ropes will be immediately withdrawn from service and destroyed.

• Load estimation must be carried out before attempting any lift, and suitable ropes and equipment with sufficient SWL will then be selected.

• Ropes must be kept free from grit, grease, general dirt and moisture.

• No rope should be left in a wet state. This applies in particular to natural fibre ropes.

• Ropes stored on vehicles must be kept clear of any cutting tools.

Care of Ropes

• Keep ropes clear of mud and grit and away from direct forms of heat and strong sunlight.

• After use, ensure that ropes are clean and dry before storing.

• They must be carefully coiled and stored in a dry atmosphere.

• Dampness can cause rot and mildew, which will destroy the cordage.

• Dirty rope should be washed in clean running water and dried naturally in a well aired, frost-free store.

• Cleaning ropes with chemicals and solvents should only be carried out in accordance with the manufacturer’s instructions.

• Ropes must be regularly examined for signs of wear.

• External wear is indicated by chafing of the rope fibres and broken frayed strands.

Conductor Erection Tension at 0oC

50mm2 AAAC 411kgf

100mm2 AAAC 814kgf

150mm2 AAAC 1309kgf

200mm2 AAAC 1725kgf

50mm2 CCC 307kgf

120mm2 CCC 891kgf (11kV), 877kgf (33kV)

185mm2 CCC 1380kgf

32mm2 Copper 373kgf (LV), 730kgf (HV)

70mm2 Copper 674kgf (LV), 1402kgf (HV)

95mm2 4-core ABC 580kgf

120mm2 4-core ABC 713kgf


• Internal wear is not always visible and is caused by grit getting between the strands and fibres. Internal wear is indicated by the presence of such grit and powdered rope fibre between the strands.

• Mildew can be detected by the presence of white stains on the rope and a damp smell.

Natural Fibre Ropes

• Wet natural fibre rope will rot.

• When in storage, ropes must be loosely coiled and, where possible, hung up to ensure circulation of air whilst drying.

• Any rope severely contaminated with oil, grease or creosote must be destroyed.

• To check a natural fibre rope, twist against the lay. The rope must lie clean internally with no evidence of broken fibres. Any sign of blackening is a likely indication of rot. Test by trying to lift the fibres; if any are broken destroy the rope.

• The ends of natural fibre ropes must be made off by either an end splice, sailors whipping or coated heat-shrink tubing.

Man-made Fibre Ropes

Note: Polypropylene ropes must not be used on any friction device due to the heat generated, which will affect the overall performance of this type of rope.

• Man-made fibre ropes are generally unaffected by water, oils (including transformer oils) and grease.

• Ropes that have been subjected to grit or mud must be cleaned by rinsing in fresh water.

• Dirty ropes are unsafe ropes – grit and sharp flints caught in the rope damage the fibres and may initiate premature failure.

• In storage they must not be placed against hot surfaces as all man-made fibre ropes can be severely damaged by heat.

• Ropes, which are so badly contaminated with grease or creosote that handling is impaired, must be withdrawn from service and destroyed.

• Man-made ropes have heat sealed ends.

Steel Wire Ropes

• Always wear the correct PPE, especially protective gloves, when handling steel wire ropes.

• Steel wire ropes are usually used in conjunction with winch equipment.

Note: They must not be confused with tirfor wire ropes.

• Steel wire ropes should be stored in a clean, cool, dry environment, preferably indoors. They must not be allowed to rest on the floor, but should be stored on pallets or shelving.

• When handling steel wire ropes, care must be taken to unwind the rope from the ring or reel without torsions (kinks) and outer damage. This also applies when reeving the wire through pulley blocks etc. If the rope is rolled along the ground, care must be taken to ensure the surface is clean as sand or grit can stick to the lubricant and damage the wire when travelling over sheaves.

• Under no circumstances must the rope be pulled off a coil whilst lying on the ground or sideways off a reel; this procedure will inevitably induce one kink per wrap into the rope, resulting in a distortion of the lay and the introduction of a weak spot, leading to a reduced rope life. Steel wire ropes with kinks are not safe to operate and must be destroyed.


• New ropes, such as those installed on winches, should be ‘broken in’ under light loads so that the stranding can settle to the operating conditions.

• Steel wire ropes require regular servicing. When the rope is an integral part of an item of lifting equipment, maintenance will be carried out in conjunction with the device.

• During production steel wire ropes receive intensive lubrication to prevent corrosion and reduce friction. This lubrication only lasts for a limited period and should be periodically reapplied.

• Very dirty steel wire ropes should be cleaned externally. This is a time consuming and laborious task, which may be better outsourced to a specialist who will have the necessary equipment.

• If during an inspection the ends of broken wires are detected they must be replaced.

Inspection of Steel Wire Ropes

Two or more defects on a rope must be viewed as more serious than a single defect.

A steel wire rope will be discarded if:

• Three or more visible wire breaks are adjacent to a termination.

• Three or more visible wire breaks are seen in one strand.

• Three or more visible wire breaks are observed in separate strands within 10 wire diameters.

Inspect in the valleys between strands looking for:

• Flattening.

• Change of diameter (increase/decrease).

• Chemical attack.

• Abrasive wear.

• Waviness.

• Birdcaging, strand or core protrusion.

• Wire extrusion.

• Bends or kinks.

2.5.4.2 Safe Working Load of Ropes

Note: Table 10 allows for a FoS of 3 for pulling and 6 for lifting.


2.5.5 Ground Anchors

2.5.5.1 General

• Ground anchors are used in overhead line work for a variety of reasons. They are usually of a temporary nature but they can be required to take a large amount of tension.

• The type of ground anchor used will depend on the construction of the overhead line, the duration for which it will be used, the angle at which it is installed and site conditions.

• Ground anchors range from a simple stake in the ground to blocks buried 1.8m deep. Table 11 shows the approximate holding capacities of various types, but it must be stressed that the figures given are for good ground conditions only.

• Site conditions will determine how much load can be applied and the loads given in the table must be down-rated to suit poor ground condition.

Note: Sash cords are for hand use only.

2.5.5.2 Safe Use

Type SWL without Proof Test

SWL with Proof Test

Proof Load Continuous Long Term Load

Stay Block (250 x 125 x 500) 1800mm deep

4000kg

5500kg

6800kg

5500kg

Molex Screw Anchor1500 x 300750 x 150

110kg363kg

1800kg550kg

2250kg680kg

1630kg400kg

K & K Porcupine (included to line of pull)

450kg

725kg

900kg

550kg

Ground Stakes75 x 75 x 1050

180kg 275kg 340kg 200kg

Table 10 – Safe Working Load of Ropes

Table 11 – Safe Working Load of Ground Anchors

Nominal Diameter (mm)

Safe Working Loads

Steel Sisal Polypropylene

Pulling Lifting Pulling Lifting Pulling Lifting

6 - - - - 180 90

8 1130 565 160 80 320 160

10 1170 885 210 105 475 237.5

12 2545 1270 318 159 675 338

14 3465 1730 428 214 930 465

16 4530 2265 600 300 1165 583

18 5730 2865 710 355 1480 740

20 7065 3530 950 475 1790 895

22 8565 4280 1130 565 2165 1080

24 10200 5100 1355 678 2530 1265


• Most ground anchors will yield considerably under load conditions. Some like the Molex type will continue to yield after load has been applied. Ground stakes yield very little, but fail quickly once they reach their ultimate load.

• Proof loading of ground anchors is sometimes advisable, especially in poor ground conditions. A load of 1.25 times the SWL of the anchor must be applied, this will also have the effect of ‘bedding in’ the anchor and help to reduce yield.

• Wood or concrete blocks buried up to 1.8m deep and fitted with either wire rope sling or stay wire are possibly the best type of anchor, mainly used for steel tower and heavy duty construction.

• Temporary augered stay rods are now available and these make an excellent heavy duty stay anchor. They are also proof loaded as they are installed, as a reading on the hydraulic gauge can be directly converted to a holding capacity for the anchor.

• Broughton anchors and K & K anchors are easily installed by hammering steel pins through the anchor frames and into the ground. They work effectively on a horizontal plane but have a tendency to lift if the load is at an angle; this effect can be countered by digging an inclined slot to take the anchor. Holding capacity again depends on ground conditions. Broughton and K & K anchors can be linked in parallel with a sling and a ‘floating’ block to increase their holding capacity.

• Ground stakes provide a quick method of providing an anchor. Stakes must be driven into the ground at an angle of approximately 60° and the load must be applied as close to the ground level as possible.


2.5.6 Knots

2.5.6.1 General

Note: When forming knots always make allowance for initial slippage when weight is applied. Leave sufficient tail on the non-working part of the rope to allow for this.

2.5.6.2 To Join Two Lengths of Rope

Type of Knot Usage Figure 16

Reef Knot This knot has many purposes as it holds firm and can be easily undone. It is generally used for joining two ropes together of equal size

Knot 1

Fishermans Knot

This knot can be used for joining two ropes together, which are wet and slippery

Knot 2

Sheet Bend This knot is used for joining two ropes together of different sizes, where splicing is not required

Knot 3

Knot 1 - Reef Knot 1 2

Knot 2 - Fishermans Knot

Knot 3 - Sheet Bend

Figure 16 – Knots to Join Two Lengths of Rope

Knot 1 – Reef Knot

Knot 3 – Sheet Bend

Knot 2 – Fishermans Knot

Table 12 – Types of Knots for Tying Two Lengths of Rope



Clove Hitch This hitch is used to attach a rope to an object where a knot that will not slip along the rope is required. It can be applied to poles but is more often used when attaching the end of a rope to an iron bar or post

Knot 4

Round Turn And Two Half Hitches

This hitch is used for attaching a rope for anchoring or snubbing. It is easily and quickly made and untied. It can be applied to poles

Knot 5

Rolling Hitch This hitch is a non-slipping hitch used for putting round a spar or another rope made as a clove hitch but with a round turn put in between the two half hitches

Knot 6

Timber Hitch The timber hitch is a very sound hitch when attaching the loose end of a rope to a pole. The more tension that is applied to the rope, the tighter it grips. It can be undone very easily after use

Knot 7

Waggoners Hitch The waggoners hitch is used to provide extra tension on pulling conductors to tension, plumbing poles and holding out transformers

Knot 8

Knot 4 - Clove Hitch

Knot 5 - Round Turn and Two Half Hitches

Knot 6 - Rolling Hitch

1

2

4

3

Second WrapBehind First

ToFixed Point

AnchorPoint

5

Knot 8 - Waggoner’s Hitch

Knot 7 - Timber Hitch

Figure 17 – Hitches to Pull or Lift Poles or Spars

Knot 4 – Clove Hitch

Knot 6 – Rolling Hitch

Knot 7 – Timber Hitch

Knot 5 – Round Turn and Two Half Hitches

Knot 8 – Waggoner’s Hitch

Table 13 – Types of Knots and Usage

2.5.6.3 Hitches to Pull or Lift Poles or Spars



Sheep Shank This knot is used for shortening a rope without cutting it Knot 9

Bowline The bowline is used when a loop is required in the end of the rope. It will not slip or pull tight. Extremely useful when pulling up conductors

Knot 10

Running Slip Knot This knot is good for a variety of general applications Knot 11

Figure 18 – Loops and Harnesses

Knot 9 - Sheep Shank

Knot 10 - Bowline

1

2

43

Knot 11 - Running Slip Knot

2.5.6.4 Loops and Harnesses

Knot 9 – Sheep Shank

Knot 10 – Bowline

Knot 11 – Running Slip Knot

Table 14 – Types of Knots and Usage


2.5.7 Tirfor

2.5.7.1 General

Refer to Figure 19 – Tirfor and Figure 20 – 3-Tonne Type.

The Tirfor is a hand operated pulling and lifting machine including a steel rope with full rope travel.

Figure 19 – Tirfor

Rear View

Tirfor

Pulling StrokeOperating Lever

ReleaseCatch

RopeReleaseLever

Front View

Table 15 – Tirfor Ratings

Lift SWL Pull SWL Wire Rope Size

880kg 1200kg 8.2mm

1600kg 2500kg 11.3mm

3200kg 5000kg 16.3mm


It works by pulling directly on the rope, the pull being applied by two pairs of self-energising smooth jaws which exert a grip on the rope in proportion to the load being lifted or pulled. The initial pressure which causes the jaws to grip the rope and give the self-energising action is provided by powerful springs. The two levers actuating the jaws provide a forward or backward motion to the rope, depending on which lever is used.

Tirfors use a special wire rope known as ‘Maxiflex’, this type of rope must only be used with a Tirfor. The ropes have a hook or eye at one end and are tapered and fused, to allow easy installation, at the other end. Three sizes are used 8.2mm, 11.3mm and 16.3mm.

Tirfors are available in different sizes with various SWLs. Some tirfors have a different rating for lifting or pulling. Please refer to Table 15.

2.5.7.2 Setting up a Tirfor

Refer to Figure 21 – Operating the Tirfor

1. Lubricate the unit generously before starting.

2. Uncoil the wire rope in a straight line to prevent loops, which might untwist the strands or form kinks when under tension.

3. The following instructions assume that the machine anchor hook points away from the operator.

With the right hand, push in and maintain pressure on rope release catch C on the side of the casing by the hook, and with the left hand pull the rope release lever P away from the hook until it is vertical. Release catch C and continue to pull back on the rope release lever P until it locks into position. Both jaws are now open.

Figure 20 – 3-Tonne Type

Neutral

LowerHandle

LiftHandle

NeutralEngageHandle

Front View

Only use the Handle Extension Supplied by theManufacturer for Raising and Lowering Loads

Engaged

Rear View

Tirfor3 Tonne Type

Note:


4. With the machine lying on the ground, insert the fused and tapered end of the rope at A. This is the best position for feeding the rope between the jaws. Push the rope through until it emerges at B.

5. Anchor the machine and the cable hook with the correct slings, and ensure that the safety catch is closed.

6. Pull the wire rope by hand until the rope becomes tight on the load.

7. To engage the machine on the rope, ease the rope release lever P away from the hook, press and maintain pressure on the release catch C on the side of the machine. Allow the release lever P to slowly travel back to its original position.

8. The rope is now firmly fixed in the jaws of the machine. To operate the machine, place the operating handle on the pulling stroke operating lever and lock it into position by twisting, then move the operating handle backwards and forwards.

9. The rope moves through the machine on both forward and backward strokes of the lever.

Figure 21 – Operating the Tirfor

Selected Tirfor Rope

Insert the Rope

To engage the machine, ease the rope release lever P away from the hook, press and hold release catch C. Allow lever P to slowly travel back to its original position.

Operating Handle

Tirfor

Engage the operating handle, twist to lock in position and move the handle forwards and backwards.

Pull the rope through until tight on the load.

P

C

Anchor Slings


2.5.7.3 Tips When Using a Tirfor

General

• Ensure that the lifting or pulling effort to be exerted is within the rated capacity of the machine.

• Use only the operating handle supplied with the machine. Its length has been designed to operate the Tirfor machine within its rated capacity.

• Safety catches when fitted must be fully closed; hooks without safety catches must be moused (secured with turns of rope).

• Never stand on or under a load whilst in motion.

Anchoring Tirfor

• Ensure that both the anchor sling and the anchorage are of sufficient strength to hold the load. As soon as the load is applied, check this once again.

• Check the anchorage points are strong enough to take the weight (proof load of SWL plus 25% may need to be applied to ground anchors).

• Ensure that there are no obstructions around the machine, which could prevent the rope, machine and anchor from operating in a straight line.

• The length of the machine anchoring sling must be such that the machine is in a comfortable position to use.

• Never anchor the machine by the tip of the hook.

Tirfor Ropes

• When in use, keep the rope in a straight line from the machine; failure to do so will cause the rope to bird-cage.

• Wire ropes must be uncoiled, throwing rope from the reel will cause kinks.

• Keep the rope clear of sharp edges. Rope used in one area can wear quickly and cause the Tirfor to slip.

Using Tirfor

• Never attempt to release the Tirfor machine with a load on the rope.

• Never operate the forward and reverse levers at the same time.

• To open the safety catch, depress the butterfly inwards and the catch will fly outwards. To close, simply push the catch down into the hook.

• Do not operate the Tirfor machine when the rope ferrule gets to within 100mm of the machine. Otherwise, the ferrule is likely to foul the casing and push the rope guide inside the machine.

• Shear pins are fitted to the power stroke lever shaft on the smaller tirfors, allowing the lever to slip freely if excessive strain is applied. The reversing lever is unaffected, allowing the load to be released.

Gearing and Increasing Lifting Capacity

On the larger tirfors it is possible to change the gearing. Never operate the lowering lever whilst the machine is in high gear.

Tirfor ropes can be used in conjunction with either single or multiple blocks to increase the lifting capacity (Refer to 2.5.9). Pulley blocks used must have a sleeve diameter ratio of 15:1 to the wire rope diameter, and the sleeve groove must be compatible to the wire rope.


2.5.7.4 Maintenance and Storage

• After use thoroughly clean any dirty equipment and allow to dry out naturally.

• Generously lubricate the machine with either grease or engine oil. Do not use any lubricants containing MOLYBDENUM DISULPHIDE.

• Hang the machine by the hook on a rack or store clear of the ground in a dry environment.

• Always remove the rope from the machine when storing for any length of time.

• Wire ropes must be cleaned, lubricated and wound onto a drum or special rope holder.

• Wire ropes subject to frequent use in wet conditions must be checked for internal corrosion (Tirfor ropes have a wire central core, unlike normal wire rope).

• Keep wire rope away from direct heat and store clear of the ground.

• Check to ensure manufacturer’s nameplate (with SWL identification number) and the UK Power Networks Identification and Inspection tag are clearly visible.

2.5.8 Lever Lift Blocks

2.5.8.1 Pul-lifts

General

• Pul-lifts are widely used for overhead line work.

• A pul-lift is a lever operated block, which gives the user a considerable mechanical advantage.

• The block can be either reeved with link chain, roller chain, steel wire or fibre webbing. It is fitted with a hook at either end.

• They provide a relatively light lifting appliance that can be used in any plane. Comparatively short lifting capability limits its use to small variations in moving loads.

• This is ideal for tensioning overhead line conductors as a very precise movement can be easily achieved.

• They are usually fitted with a friction clutch lining which controls movement of chain.

Figure 22 – Example of a Pul-lift


Safe Uses

Pul-lifts must be checked before use to ensure they are in good order. Particular attention must be given to:

• The load chain shall be free from kinks, twists, distortion, corrosion and stretches. A check must also be made to make sure the chain runs freely.

• Hooks shall be un-opened and shall not be deformed, bent, cracked or gouged. Safety catches are in good order.

• Anchor or stop is fitted to the free end of the chain to prevent chain run through.

• The body casing of a pul-lift must not be cracked or distorted. All nuts or screws are in place and tight, and no debris has built up in the casing.

• Ratchet Action – Ensure the ‘up’, ‘down’ and ‘neutral’ lever operate correctly. The clutch mechanism holds and releases as required.

Additionally:

• Check UK Power Networks Inspection tag is attached and legible.

• DO NOT USE ANY SUSPECT EQUIPMENT. Return suspect equipment with suitable label attached to the supervisor.

• Carry out a load estimation before selecting a pul-lift, Do not exceed the SWL of the pul-lift.

• Ensure suitable anchor points are selected, if connecting the pul-lift to slings; use a shackle if the angle of the slings is too great.

• Do not apply undue force or extend the lever of the pul-lift artificially (e.g. scaffold tube).

• Pul-lifts must not be dropped from a height or dragged along the ground.

• Do not use anchor points that place undue strain on the load hooks.

• Never choke the chain back on itself.

• On a pul-lift with a multi-fall link chain check to ensure that the hook is not turned completely through the chain.

• Do not overcrowd the load hook with slings.

Maintenance and Storage

Keep the pul-lift clean and store in a dry environment. Lubricate lightly. Over lubrication could contaminate the clutch lining and lead to slip under load conditions. It could also lead to premature chain wear due to the abrasive effect of dirt adhering to the chain.

Hang by hooks when it is not in use. Do not dry by applying direct heat.

Pul-lifts must have SWL, identification number and UK Power Networks current colour code clearly marked.


2.5.8.2 Ratchet Lever Hoist (Lug-all)

Refer to Figure 23 – Ratchet Lever Hoist (Lug-all)

Lug-alls are drum winches using either fibre straps or wire rope and are individually identified and marked with SWL and certificated.

Lug-alls are also known as come-a-long ratchet lever hoists.

Note: Lug-alls must be treated as pul-lifts.

• Ensure that there are no obstructions around the machine which could prevent the rope machine and anchor from operating in a straight line.

• When the machine is fitted with a double cable rig, care must be taken to ensure no overloading takes place when used singularly.

• There is a fast take-up on the drum through a side wheel or winding handle and a fast run-out by using a trigger.

• Although these machines have a multi-notch pull, the slacking off is by one notch at a time until the load has been released.

• Some lug-alls are fitted with an overload shear plate on the handle mechanism, which will give notice of overload; the parallel plate will still allow operation of the machine to relieve the load.

• It is essential that these open case machines are kept clean and that any grit is immediately removed.

Figure 23 – Ratchet Lever Hoist (Lug-all)


2.5.9 Single/Multi-sheave Blocks and Pulleys

2.5.9.1 Definitions of Blocks and Pulleys

Snatch Block

A block that can be opened on one side to receive the looped part of a rope.

Running Block

A block in an arrangement of pulleys which rises or sinks with the weight which is raised or lowered.

Pulley

• A simple machine consisting essentially of a wheel with a grooved rim in which a pulled rope or chain can run to change the direction of the pull and thereby lift a load.

• A wheel turned by or driving a belt.

Pulley Block

A pulley or a system of pulleys set in a casing.

Sash Line Blocks

A simple single block temporarily attached to the pole to support a sash line being used to raise tools and light items of equipment.

2.5.9.2 Rope Blocks (single or combined single/multi-sheave blocks)

Refer to Figure 24 – Definitions of British/European and US Standards

Irrespective of whether British/European or American sheave blocks are used, the SWL must be taken as the load on the head fitting, therefore a minimum size of 4 tonnes SWL must be used for all overhead wood pole work, other than for sash-line blocks.

2T

1TEffort

1TLoad

BlockMarked1T SWL

1T

500kgEffort

500kgLoad

BlockMarked1T SWL

Figure 24 – Definitions of British/European and US Standards

British/European US

Note: No allowance has been made for the effect of friction on these blocks. This equates to an additional 8% on the effort required to raise the load.


General

• Rope block pulleys are designed for a particular size of rope. It is dangerous practice to use a rope other than that for which the pulley wheel was manufactured.

• The ratio between the rope diameter and pulley (sheave) diameter is a critical factor that influences rope life.

• As a general guide, the sheave to rope diameter ratio must be not less than 18:1 to give reasonable rope life.

• The same principles apply to sheaves as to rope drums with regard to bending ratios and radial pressures.

• It is also important for optimum rope life that the sheave groove profile is matched to the rope diameter.

• If the groove is too small the rope will be ‘pinched’ as it is forced into the groove under the influence of load, damaging both the rope and sheave.

• If the groove is too large, there may be insufficient support for the rope, which may become flattened and distorted under load, thus accelerating failure.

• Since a worn sheave can damage a rope, it is necessary, before fitting a new rope, to check that the sheave is free running and that the whole profile is free from ridges and is smooth. The sheave groove must be checked periodically for wear and damage.

Using Single and Multi-sheaved Blocks

Refer to Figure 25 – Single or Combined Single/Multi-sheave Blocks.

• When the SWL is applied to a block, rigged as a single sheave block, the load on the head fitting will be twice the SWL.

• With the block inverted it follows that twice the SWL of the block can be raised or pulled.

• With a combination of single or multi-sheave blocks, the SWL of the arrangement will depend upon the method of rig.

• An allowance must be made on the lifting force of approximately 8% per rope part for single or multi sheave blocks.

Inspection and Care

• All metal parts must be free from rust and checked for cracks or distortion.

• All welds and rivets must be intact.

• All bearings must be free running and well lubricated. Excess wear must result in the unit being withdrawn from service.

• Ropes must be checked according to type. Refer to Section 2.5.4. Particular attention must be paid to splices and anchor points.

Storage

Where possible, rope blocks are to be hung to allow free air circulation.

Where blocks cannot be hung they must be stacked with rope neatly coiled clear of the ground and turned from time to time.


2.5.10 Slings

2.5.10.1 Definition

• Slings are the components used to link either the load or an anchor point to the lifting appliance.

• Various types, lengths and configurations are available, but the preferred type for overhead line work is usually the polyester round sling. They are favoured for overhead line work because of their flexibility, lightness, strength and cost.

• Wire rope slings are still used for overhead line work although not as frequently as in the past.

• Wire rope, chain and webbing slings are also available in single and multiple configurations.

• Chain and webbing slings are even less frequently used, although there are occasions when they are in service as part of other equipment e.g. ABC rollers, pole platforms.

2W

2WW

1.5W

W

2

W

R

Single Sheave Block

Combined Single/Multi-Sheave Blocks

W = Safe Working Load as Marked on Block

SingleSheave

SingleSheave

LoadW

EffortE

W W

W

2

W

2

1.33W

W

3

R

DoubleSheave

Typical Methods of Rigging

SingleSheave

Rope BlocksSafe Working Loads

LoadW

EffortE

W

3

W

3

W

3

1.25W

W

4

R

DoubleSheave

DoubleSheave

LoadW

EffortE

W

4

W

4

W

4

W

4

Figure 25 – Single or Combined Single/Multi-sheave Blocks


2.5.10.3 Slinging Safely

It is important to decide on the sling configuration to be used and refer to Figure 26 – Slinging Configurations to determine the de-rating factor to be applied.

Reference should also be made to Figure 27 – Slinging Practices.

• Find out the weight of the load to be lifted. Do not use the sling for any load exceeding its stated SWL.

• Examine all slings before use and discard any that are defective.

• Do not use a sling which contains a severe kink.

• Slings which are found to be unfit for use should be destroyed, not put on a refuse dump.

• When using multi-leg sling assemblies, remember that the angles between the legs will reduce the SWL of the assembly. Consult the sling chart and SWL tables available.

• Endless wire rope slings are prone to misuse, and in practice they are often found to be difficult to handle. It is preferable that they are used only when they have been purpose made for applications requiring a very short effective length or for heavy lifts where a single sling of the required SWL is not available.

• Avoid bending wire rope slings around sharp corners of the load as it could effectively reduce their SWL.

• Do not drag wire rope slings along the floor.

• Suitable packing from sharp edge of the load should protect wire rope slings.

• Keep wire rope slings away from welding and flame cutting operations.

• When loads are being carried on a crane hook, slings not in use should not be carried on the same hook.

Colour SWL (Ideal conditions)

Violet 1,000

Green 2,000

Yellow 3,000

Red 5,000

Blue 8,000

Grey 12,000

Brown 20,000

Orange 24,000

2.5.10.2 Safe Working Loads

Slings can be purchased for virtually any application. They can be purpose made for a particular job. The range of SWL for slings is therefore very comprehensive, from 500kg to over 60 tonnes.

Polyester round slings, favoured by overhead line teams, range from 1 tonne to 12 tonnes. These SWL sometimes have to be down rated, dependent on the method of slinging, they are colour coded for ease of identification.

Table 16 – Colour of Slings for SWL


• Check that the crane hook is positioned over the load’s centre of gravity to prevent swinging when the load is being raised.

• Correct signals, according to the recognised code should be given to the crane driver. The person responsible for the lift and nobody else must give the signals.

• Make sure that the load is free before lifting, and that all sling legs have a direct load.

• Ensure hands are away from the slings before the crane takes the load, and stand clear.

• Never allow the load to be carried over the heads of other persons.

• Do not ride on a load that is being slung, nor allow any other person to do so.

• Steady application of the load at the start of each lift will avoid risk and prolong the life of the sling – beware of snatch loading.

• Always lower the load on to adequate batons to prevent damage to the sling.

Figure 26 – Slinging Configurations

SWL Straight Lift 100%

Roundsling SWL and Included Angle

SWL Choked 80%

SWL 200%

SWL 45o Lift 100%

SWL 900 Lift 100%

SWL 200%

SWL 100%

SWL 192.5%

SWL 172.5%

SWL 140%

SWL 100%


NoKinks in Ropes

NoSteel RopesOver SmallRadius Hardware

NoBackhooking

NoHooks OverSmall RadiusHardware

NoHooks inSmall Holes

UseSlings Protected fromSharp Edges byWood and Rag

Use‘D’ Shackles inSmall Holes

UseSaflock HookFor Snatch-Blocks

UseSling Eyes on‘D’ Shackles

Malpractices Good Practices

Slings

Figure 27 – Slinging Practices

No Kinks in RopeUse Sling Eyes on ‘D’ Shackles

Use ‘D’ Shackles in Small Holes

Use Slings Protected from Sharp Edges by Wood and Rag

Use Saflock Hook for Snatch Blocks

No Steel Ropes Over Small Radius Hardware

No Hooks Over Small Radius Hardware

No Hooks in Small Holes

No Backhooking

Malpractices SWL and Included Angle



• Slings must be hung clear of the ground in a dry environment, free from excessive changes in temperature.

• Wire rope and chain slings must be lightly oiled (do not use contaminated oil i.e. used engine oil). Care must be taken if using wire rope slings in a continually wet atmosphere; corrosion may begin internally and therefore be hard to recognise.

• Polyester slings are to be stored out of direct sunlight, in an unpolluted area.

• Wet slings must be allowed to dry naturally.

2.5.11 Shackles

2.5.11.1 Definition

• Shackles are the components used to connect items of lifting gear to each other, or to specific lifting points (maintenance plates on towers, lifting eyes on transformers etc).

• Different grades of material are used to make shackles. High tensile steel and alloy steel are the most common.

• Alloy steel shackles are considerably stronger, size for size, than other materials used for shackles.

• Generally there are two types of shackle that are used on overhead line work – ‘D’ shackles and bow shackles.

• The main difference between ‘D’ and bow shackles is the width of the loading area.

• There are two sizes of shackle available:

• large shackles for general purpose work.

• small shackles for use with hooks, eyes, links etc.

• A small shackle with a SWL of 1 tonne would be used to connect a wire sling to a lifting eye, whereas a large shackle, again with a SWL of 1 tonne, would be used for multiple sling connection.

• A shackle pin is fitted to the open end of the shackle; this can be removed to allow fittings to be installed into the body of the shackle.

• Only the pin supplied with the shackle must be used, trouble could arise if pins of different grades of steel are used.

Figure 28 – Shackles


2.5.11.2 Safe Working Loads

• Estimate the load to be fitted and select shackles with sufficient strength.

• Shackles for wood pole overhead line work must range in size from 1 tonne SWL to 3 tonne SWL. For steel tower work, shackles with a higher rating are required for some procedures (6 tonne).

• Shackles for general use can be purchased with SWLs between ½ tonne and 100 tonnes.

2.5.11.3 Safe Use of Shackles

• Do not use shackles that form integral parts of overhead line equipment for lifting operations.

• Carry out load estimation and select shackles with sufficient SWL.

• Before using a shackle, check for:

• Wear in the body or pin.

• Distortion of the body or pin.

• Cuts, cracks or gouges.

• Check the thread of the body and pin, ensuring the pin can be screwed fully into the shackle body.

• SWL and identification number are visible.

• The shackle has undergone a recent periodic inspection and is in-date.

• Check the pin is the same grade as the body and it has not been replaced by a standard bolt.

• Alloy steel shackle pins can be recognised by flats on the side of the collar or head.

• Look out for shackles that have been shock loaded.

• Shackles are designed to take the load in a straight line through the centre of the body and pin. Never lift sideways onto a shackle connected to a lifting eye or bracket.

• If a shackle is going to have a rubbing effect on any materials, ensure that its placement does not allow the pin to unscrew.

• When using a shackle to secure the top block of either single or multiple blocks, the load on the shackle will be equal to the weight of the load being lifted, plus the effort required to lift the load, plus 8% per sleeve allowance for friction.


• Store in a manner that will not cause any damage to the threaded part of the shackle body or pin.

• Keep shackles clean and lightly lubricated.

• Never return damaged shackles to the storage area.


2.5.12 Winching

2.5.12.1 Safety when Winching

Wear the appropriate PPE, namely:

• Ear defenders if 90 decibels (winch 90 – 110dB).

• Gloves – especially when handling wire rope.

• Protective footwear.

• Eye protection (if required).

• Hi-visibility jacket.

• Hard hat for OHL work.

• Gloves/barrier cream if handling oils, hydraulic oil, grease etc.

If working on the public highway ensure:

• Signing, lighting and guarding is correctly deployed, including a Safety Zone for staff around work area.

• Adequate precautions are taken for the safe passage of pedestrians and vehicular traffic around the works.

2.5.12.2 Precautions when Winching

• Never overload the winch. Estimate the load to be lifted and check that this is within the winch capability. Also refer to 2.5.3.

• Know SWL of winch, pulling rope or wire bond. Carry out load estimation.

• Ensure the winch is securely anchored and will not move under load. Ensure that the winch is in line with the load or the pulley system. Proof load winch anchor before using (1.25 x load).

• The winch operator must be a minimum of 3m away from base of pole when lifting items of plant.

• If winching from directly behind pole, try to ensure that the winch is positioned 2 x height from pole.

• Give clear and recognised signals to the winch operator. A signaller is to be nominated before start of a lift.

• Ensure good communication over length of job.

• Never lift a load unless it is safely slung and balanced.

• Ensure the load is free before taking the weight.

• Remove hands from ropes or chains before taking weight and stand clear.

• If any circling of the wire winch rope occurs, this usually indicates over-tensioning.

• Never use winch to lift people.

• Never lift or suspend loads over people.


2.5.12.3 Wire Winch Ropes

• The ratio between the rope diameter and winch drum diameter is a critical factor that influences rope life, reducing bending ratios and radial pressures. As a general guide, the drum to rope diameter ratio must be not less than 18:1 to give reasonable rope life. Any pulley blocks used to direct winch bond must have same sheave criteria as above.

• Steel core ropes are best suited for winch applications – less resistant to crushing, deformation, elongation and are stronger than fibre ropes. Fibre core ropes must not be used as winch ropes. Anti-twist ropes can be used for winch ropes.

• If anti-twist ropes are not used, swivel hooks or swivel attachments must be used in the winch rope.

• Wire rope dressing will prolong life of rope.

2.5.12.4 Paracore Rope Winch Ropes

Storage

It is important to note that in manufacture the outer cover of Paracore rope is tightly plaited over the parallel core yarns whilst the core is under tension. If the rope is allowed to relax, and not kept under a degree of tension (i.e. tightly wound on a drum or reel), the contraction of the core can cause lumps in the rope and, in some cases, elements of the core yarns pop out through the cover plait.

Although sometimes unsightly, these appearance imperfections do not harm the properties of the rope and disappear immediately when tension is applied. Paracore should therefore only be stored under tension on a drum or reel preferably in a cool, clean, dry place away from sources of heat and direct sunlight.

Care, Inspection and Maintenance

Do not pull rope over sharp edges. Ensure all stringing rollers are mounted correctly, run freely and are of a suitable size. Avoid contamination from dirt, rust, paint, oils, chemicals and fumes. Wash rope in cold running water if necessary.

Only use crimped rope eye. If the rope is damaged and a new eye is required, this must be done by an approved company. Do not under any circumstances use a knot as this will weaken the rope significantly.

Regular inspection of the rope in conjunction with annual examination of the winch is recommended. Examination of 300mm of rope at a time is recommended, the rope being turned to reveal all sides before continuing. At the same intervals, the strand should be opened just sufficiently to allow examination of inside bearing surfaces.

Replace the rope immediately if there are any signs of excessive wear, abrasion, scoring, glazing, powdered fibre or loosening of strands.

Table 17 – Paracore Rope Breaking Strength

Paracore Diameter 7mm 8mm 9mm

Max Braking 2000kgf 2500kgf 3250kgf


2.5.13 General Precautions when Using Lifting Equipment• Wear the appropriate PPE.

• Always know the weight being lifted and ensure that it is within the SWL limits of the equipment being used.

• Ensure that the winch rope is of adequate length for the job.

• Remove hands from lifting tackle. Stand clear before the load is taken.

• When load is taken ensure that it is safely slung, balanced and secured.

• Ensure that the load is free before lifting or pulling.

• Give clear signals to the winch driver; only the person responsible for the lift or pull must give signals.

• Never permit a load to be lifted over persons. Give warnings to keep clear of the load where necessary.

• Avoid snatch and shock pulling or lifting.

• Never ride on a winch load and ensure nobody else does.

• Never leave the controls of a winch while it is in motion – if help is required stop the winch and wait until help is available.

• Loads must never be allowed to rest on slings. Place suitable packers to support the load and permit removal of the slings.

• When stacking material, ensure that the stack is stable and on a firm foundation.

• Do not stack material within 6m of a railway line.

2 SAFETY ASPECTS, PROCEDURES, TOOLS AND...

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