2357 Session Requirements of Inpection and Testing

7/29/2019 2357 Session Requirements of Inpection and Testing

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Goal Walsall College

C&G 2395-01Level 3 Award

Principles, Practices and Legislation

for the Periodic Inspection, Testingand Certification of Electrical

Installations

Session onPrepare for Initial Inspection


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Outcome 1

Identify the requirements for inspecting, testing and

recording the condition of electrical installations

Aims

State the purpose of inspection of electrical

installations

Specify the information that is required by the

inspector to conduct the periodic inspection of anelectrical installation


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A word about SAFETY


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Purpose of inspection and testing

1. The safety ofpersons and livestock against the effects of

electric shock and burns in accordance with the general

requirements of Regulations

2. Protection against damage to property by fire and heat

arising from an installation defect

3. Confirmation that the installation is not damaged or

deteriorated so as to impair safety

4. The identification of installation defects and non-

compliance with the requirements of the regulationswhich give rise to danger

GN3 3.1 Page 59


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Statutory Documents

The Electricity

Safety, Quality

and Continuity

Regulations 2002

The Health &

Safety at Work

Act 1974

The Electricity at

Work Regulations

1989


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Non-Statutory Documents


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Importance of Compliance with Statutory &Non-Statutory Documents

Before you can commence Inspection OR Testingon

installations or machines and equipment there are

certain things which must be checked FIRST!!!




It is essential that the person carrying out the

inspection and testing is COMPETENT.

The inspector must be EXPERIENCED and must be

sufficiently KNOWLEDGEABLE of the installation to be

inspected.

COMPETENT

EXPERIENCED

KNOWLEDGEABLE




The tester must ensure NO DANGER is caused to any

PERSON, LIVESTOCK or PROPERTY.

Prior to carrying out an inspection and test theinspector must be aware of the following.



Importance of Compliance with Statutory &


The person carrying out the inspection must also be

aware of the following design criteria in respect of theinstallation to be inspected.

The Health & Safety at Work Act 1974

and the

Electricity at Work Regulations 1989also requires the following information as a minimum.





Electrical installations should be designed into separate circuits

e.g. power, lighting, cooker circuits to avoid danger in the eventoffaults and to facilitate the safe operation of the inspection and

testing process.

It is a requirement of the regulations that this information

will be available

as an on-site record of design



The following images

were taken from theBuilding Regulations

Approved Document

P

Drawings, Charts and Installation Details



Circuit Details



Earthing Details





Electrical contractors that issue inaccurate or misleading

certificates or reports are liable to criminal prosecution by

the Trading Standards Officers under the

Trade Descriptions Act 1968

These prosecutions can be avoided by employing

ONLYcompetent personsto produce these certificates and reports.



Its the LAW!!!

Ignorance is

NO

Excuse



Before commencing to carry out an initial verification of aninstallation, certain information and documentation must be

available, such as that indicated on the following slides

Assessment of General

Characteristics



1. Maximum demand2. Details of number of supply live conductors

3. Earthing arrangements (TT, TN-S, TN-C-S)

4. Supply voltage, frequency, current, Ze, etc.

5. Drawings charts etc of installation details (type andcomposition of circuits, method of fault protection,

protective and switching devices, equipment

vulnerable to tests)

6. External influences

7. Compatibility

8. Maintainability


Characteristics



BS7671 (2011) Regulation 311.1

For economic and reliable design, the maximumdemand of an installation shall be assessed

In determining the maximum demand of an

installation or part thereof, diversity may be taken

into account.

Maximum Demand?

D t il f N b f S l Li




The number and type of live conductors

(Single-phase two wire a.c., three-phase fourwire a.c.) (Copper or Aluminium) shall be

determined both for the source of energy and

for each circuit to be used within the

installation.

Details of Number of Supply Live

Conductors?

E thi A t TT S t


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Earthing Arrangements TT System

E thi A t TN S S t


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Earthing Arrangements TN-S System

E thi A t TN C S S t


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Earthing Arrangements TN-C-S System

A t f G l


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The following characteristics of the supply shall be

determined by calculation, measurement,

enquiry or inspection.

1. The nominal voltage2. The current and frequency

3. The PSSC at the origin

4. The EFLI external to the installation Ze)

5. The suitability of the installation6. The type and rating of the overcurrent

protective device at the origin


Characteristics

E t l I fl C d


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External Influences Codes

A = EnvironmentB = Utilization

C = Building

E t l I fl


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External Influences

E t l I fl


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External Influences

C tibilit


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Regulation 512.1.5 CompatibilityEvery item of equipment shall be selected and

erected so that it will neither cause harmful effects to

other equipment nor impair the supply during normal

service including switching operations

SWA

Brass

Bush &

Coupler

Galvanised

metal boxfixed

outside

Compatibility

Maintainabilit


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Regulation 341.1

An assessment shall be made of the frequency

and quality of maintenance the installation can

reasonably be expected to receive during its

intended life. Those characteristics are taken

into account in applying the requirements of Part4 to 7

Maintainability


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The person responsible for inspection &

testing of an electrical installation must have:-

Sufficient skill, knowledge & experience

Sound knowledge of the particular type of installation

to be inspected & tested

A reasonable understanding of BS7671


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Understanding of some DEFINITIONS

Direct ContactBasic ProtectionIndirect ContactFault Protection

Exposed & Extraneous Conductive PartsTypes of Earthing ( TN-C-S TN-S TT )Earthed Equipotential BondingMain Bonding Conductors

Equipotential (protective) Bonding ConductorsSupplementary Bonding ConductorsCircuit Protective Conductors.


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How are we at risk of shock & how do we

protect against it

There are two ways at which we can be at risk:-

1. Touching live parts of equipment or systems

that are intended to be live

DIRECT CONTACT = BASIC PROTECTION

1. Touching conductive parts which are not

intended to be live but have become live dueto a fault

INDIRECT CONTACT = FAULT PROTECTION

Basic Protection


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Basic Protection (Direct Contact)

Requirements for Basic


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Insulation

Barriers

Enclosures

Placing out ofreach

Obstacles

Requirements for Basic

Protection

INSULATION


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INSULATION

Barriers & Enclosures


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Barriers & Enclosures

Placing out of Reach


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Placing out of Reach

Obstacles


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A part preventing unintentional contact with live parts but

not preventing deliberate contact

Obstacles

INDIRECT CONTACT (Fault


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Contact of persons or livestock with exposed conductive parts

which have become live under fault conditions

INDIRECT CONTACT(Fault

Protection)

Requirements for Fault


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Automatic Disconnection of Supply (ADS)

Double or Reinforced Insulation

Electrical Separation

Extra Low Voltage (SELV or PELV).

Requirements for Fault

Protection

Automatic Disconnection of Supply


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Automatic Disconnection of Supply

(ADS)


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By automatic disconnection we mean the fuse or circuit

breaker must operate within the stated times.

For final circuits not exceeding 32amps


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For distribution circuits & circuits above 32amps

The maximum disconnection times are:-

TN-C-S (PME) 5 seconds

TN-S (cable sheath) 5 seconds

TT (earth electrode) 1 second

Regulation 413.3.2.3 & 413.3.2.4

How much fault current is


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What makes a protective device operate within the maximum times

How much fault current is

flowing

How quick the protective device


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What makes a protective device operate within the maximum times

q p

disconnects


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Loop impedance table from BS7671

Maximum Zs for 32A Type B MCB?


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Other methods of protection against electric shock


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Double or Reinforced Insulation


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Electrical Separation


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Extra Low Voltage

(Not exceeding 50v AC)

Separated Extra Low Voltage (SELV)


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Extra Low Voltage

(Not exceeding 50v AC)

Protective Extra Low Voltage (PELV)

Exposed & Extraneous Conductive


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What are they?

p

Parts


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SAFE WORKING

Working on LIVE Equipment


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o g o qu p e t

The EAW Regulations State:-


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NO LIVE WORKING UNLESS:-

1. It is unreasonable to work dead

2. It is reasonable to work live

3. Suitable precautions are taken to prevent injury.

g

Working on LIVE Equipment


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g q p

53% of electrical incidents causing injury

are from working on

live electrical equipment

The Electricity At Work Regulations


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requires that we are competent at our work

Competence requires that we apply both technical knowledge and

experience

Competence also implies that you are awareof what you dont know.

Remember before isolatingThe person who is working must be competent to do the task.

Ignorance is no excuseif in doubt dont do it.

The task must be planned in such a way that no live working takes place.

The risks to injury must be limited. Before any isolation takes place the

correct test equipment must be used.

1989


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Outcome 1Identify the requirements for inspecting, testing andrecording the condition of electrical installations

Aims

State the purpose of inspection of electricalinstallations

State the requirements for periodic inspection

Specify the information that is required by the

inspector to conduct the periodic inspection of anelectrical installation


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This is the end of the Session not so bad after all was it!!

2357 Session Requirements of Inpection and Testing

Documents

Transcript of 2357 Session Requirements of Inpection and Testing