I n t e r n a t i o n a l F e d e r a t i o n f o r t h e S a f e t y o f E l e c t r i c i t y U s e r sF I S U E L I N F O R M A T I O N L E T T E R

As I hand over the presidency, I would like simply say how much,after three years as President of FISUEL, I believe I have understood the complexity, but also the richness and full meaning of the adjective that defines our Federation: "International".In reality, to be "international", that is to say, being representedon four continents, 20 countries together, is both a difficulty, but also a great opportunity.

A difficulty first of all because of the languages, it is obvious,but also because of concepts respective: what is evident in oneplace, because cultural or historical reasons, can not be in another place. As examples, some require evidence of third-party verification; others self-certification, or yet othersthe full responsibility lies with the tenant. These three approaches,among others, are different, and may, at first, constitute misunderstandings between their adherents. They do not haveat all the same vision.

However,It is also an opportunity, because in this diversity - once those initial barriers are surmounted - exchanges start, the ideas ofsome can be a source of inspiration for others, work on newmatters - examples photovoltaics, electric vehicles, energy efficiency, cogeneration, ... - will possibly be commenced incommon, that is saving time and making progress for everyone.That is the goal of our working groups.

Conclusion: we are very lucky. Thanks to FISUEL, even, if it is not a straight one way street, without any initial difficulties, we will reach more readily achieve, each in our own country, our common goal : the safety of electricity users and uses. In addition for countries that are still in shadow, and who havenot yet become aware of their responsibilities in this area “to ensure the safety of their citizens”, the existence of our Federation is a light. Finally, thanking the Directors who have been alongside mesince 2008 and all the members for the support they have givenme during my term of office, and confident in the future, I wish “good luck” to the new President of our Federation.

Romualdo ARIASPresident

n°18 May 2011

www.fisuel.org

Editorial

In New Caledonia (an overseas country, part of France),COTSUEL (Territorial Committee for Safety of Users ofElectricity) is the only organisation authorized to issue thecertificates of compliance for electrical installations.

Association (in accordance with the 1901 MetropolitanLaw) created by the Government (territorial DeliberationNo. 468 of November 3, 1982), this third party organiza-tion was born of the willingness of local authorities and theelectricity sector (installers and energy distributors), whowanted to establish an independent body able to rule onthe conformity of electrical installations.

CONSUEL, in Metropolitan France, has been one ofthe architects of the successful setting up of COTSUEL.

Indeed it is the Articles and working methods of this"brother", which were selected for its mission to requirethe verification of electrical installations.

Today, COTSUEL’s know how is developed from near-ly 30 years of experience of daily contacts on the ground,with all professionals in the electrical industry. A know-how inseparable from the uniqueness of the methodused – verification by directed sampling, which combinesefficiency and lower cost – and also from the rigour withwhich it is applied incarry out the mission entrusted toCOTSUEL.

Installations are divided into two "families", the installation in residential buildings and those in buildingssubject to specific regulations (ERT, ERP, IGH)

COTSUEL handles every year an average of 3,000 certi-ficates of which 2,500 for dwellings. �

BP 1440 – 98845 NOUMEA CEDEXTel : (687) 27 14 77 – Fax : (687) 27 30 54Secretariat@cotsuel.nc – www.cotsuel.nc

News: new member to join FISUEL

� Active member

F I S U E L I N F O R M A T I O N L E T T E R

Present situation Europe has an ageing housing

stock. There are many homes withoutdated wiring that is deteriorating,inappropriately amended or insuf-ficient for the electrical loads of a typical household today. Many of thehomes have never undergone any renovation their electrical installa-tion, while, at the same time, the use of electricity in homes has been increasing during the last 40 years.

Fortunately, the principle of perio-dic inspection of the electrical installation is growing rapidly.

In this paper we will focus on thepractice of inspections and we willemphasise the importance of carryingout measurements, in addition to thevisual inspection.

Why inspection?We cannot imagine homes without

electrical installations. But electricityin the home introduces two majorhazards: fire and electric shock. Electrical defects are one of the common causes of fire. It is knownthat electrical fires in residentialbuildings result in more damage and higher death rates on averagethan non-electrical fires.

Various studies have alsoshownthat the costs associated with elec-trical fires in residential buildings are much larger than the costs associated with electrical shock casualties.

To counteract these hazards, theauthorities and the standardisationbodies drew up wiring rules, whichapply to the design and erection ofinstallations.

There is no point in setting upthese rules if it is not verified that they have been followed and thus an adequate level of safety has beenobtained.

But the majority of the domesticelectrical installations in Europe werebuilt more than 30 years ago and donot comply with the present safetystandards.

It is therefore important that exis-ting installations are also inspected.

DefinitionsThroughout this document we will

use the following definitions, as givenin the IEC 60364-6 ” Low-voltageinstallations - Part 6: Verifications”.

• Verification: all measures bymeans of which compliance of theelectrical installation with the relevant requirements is checked.

• Inspection: examination of anelectrical installation using all thesenses in order to ascertain correctselection and proper erection ofelectrical equipment.

Note: the word “inspection” has re-placed “visual inspection” indicatingthat all the senses (touch, hearingand smell, as well as sight) must beused.

• Testing: implementation of mea-sures in an electrical installation bymeans of which its effectiveness isproved.

• Maintenance: combination of all technical and administrative actions, including supervision ac-tions, intended to retain an item in,

or restore it to, a state in which itcan perform a required function.

Initial and periodic verification

A distinction is made between initial and periodic verification.

Initial verificationThe initial verification takes place

upon completion of a new installa-tion or upon completion of additionsor alterations to existing installations.

The aim of the initial verificationis to determine whether the require-ments of all the applicable prescrip-tions have been met. This is achievedby inspection and by testing.

Before testing begins it is impor-tant that a full inspection of thecomplete installation is carried out.

This is to confirm that the electri-cal equipment and materials:• Are in compliance with the safety

requirements of the relevant equip-ment standards

• Have been correctly selected anderected to the relevant rules and regulations and to the manufac-turer’s instructions, in order that is performance is not adversely affected

• Are not visibly damaged so as to impair safety

• Are suitable for the prevailing en-vironmental conditions

This is done by checking the me-thod of protection against electricshock, the protection against thermaleffects, the precautions against propagation of fire, the selection ofthe conductors for current-carryingcapacity and voltage drop, the choiceand settings of the protective devices,the presence and the correct locationof suitable isolating and switching devices, the selection of equipmentand protective measures appropriateto external influences, the correctidentification of the circuits, overcur-rent protective devices, switches, terminals, …, the presence of dia-grams, warning notices or similar

Inspection of electrical installationsin homesMeasurements are absolutely necessary

condition? Periodic verification will benecessary to verify that condition.

Periodic verificationAlthough is true that electrical

installations do not deteriorate quic-kly, and therefore do not require muchmaintenance, they do not however retain their original condition: damage,corrosion, degradation of material, degradation of the insulation (the insulation hardens and it can crack),connections become loose, excessiveelectrical loading, ageing, environ-mental influences, normal wear andtear, …

Apart from deterioration over theyears, the functionality of the elec-trical installations does not followthe ever-changing needs of its occupants: • More power sockets are needed.

A recent survey in the UK revealsthat two-thirds of the Britons saythat they don’t’ have enough plugsockets in their homes!

• More lighting points are needed,

• There is an increased awarenessof safety, therefore:

• There is a need for an earthingarrangement,

• There is a need for RCD’s (Resi-dual Current Device).

Therefore the electrical installationsshould be maintained in a good andsafe condition to prevent danger. Part of this maintenance should be aregular verification that includes anappropriate system of inspection andtesting.

A periodic inspection is an inspec-tion on the condition of an existingelectrical installation to identify, in

information, the adequacy of theconnections of the conductors, thepresence and adequacy of protectiveconductors, including equipotentialbonding, the accessibility of the equip-ment for convenience of operation,identification and maintenance.

In practice, this means checking thefollowing items: good workmanship,separate circuits, adequate numberof circuits, adequate number of socket-outlets, all circuits suitably identified, a suitable main switch pro-vided, main isolators to break all liveconductors, main earthing terminalprovided, correct fuses or circuit brea-kers installed, all connections secure,the installation earthed in accordancewith national standards, main equi-potential bonding connects servicesand other extraneous-conductive-parts to the main earth facility andsupplementary bonding has been pro-vided in all bath and shower rooms.

More specific, concerning the protection against direct contact, the following items will be checked:- Insulation of live parts,- Enclosures have a suitable degree of

protection appropriate to externalinfluences,

- Enclosures have cable entries cor-rectly sealed,

- Enclosures have unused entriesblanked off where necessary.

After inspection, testing will becarried out.

The following tests should be carried out: continuity of conductors,insulation resistance of the electricalinstallation, protection by SELV, PELVor by electrical separation, automaticdisconnection of supply, measure-ment of the resistance of the earthelectrode, measurement of the fault loop impedance, polarity test,functional and operational tests, voltage drop.

When the results of the initial verification are positive, the electricalinstallation is in a good condition. Butdoes the installation retain its good

order of priority, any deficienciesagainst the safety standards for elec-trical installations. Periodic inspectionsshould comprise a detailed examina-tion of the installation. They can becarried out without dismantling, orwith partial dismantling the electricalinstallation.

A periodic inspection will reveal ifany of the electrical circuits are over-loaded (and thus that more circuitsshould be provided) and will revealother potential electrical shock risksand fire hazards in the electrical installation.

By using a simple, inexpensive system of looking for visible signsof damage or faults, some of theelectrical risks can be controlled.But, this will need to be backed upby testing.

Is a periodic inspection needed?

Every installation deteriorates withuse and age. Therefore one must besure that the safety of users is not putat risk and that the installation conti-nues to be in a safe and serviceablecondition.

Let’s have a closer look at the mainparts of the installation that play aimportant role in the safety of anexisting electrical installation.

Connections

n°18 May 2011

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In case of a bad contact, the re-sistance of the contact increases,causing a temperature rise. As thishappens on a small surface, there isa limited heat drain and the tempe-rature raises even more. Soon theinsulation, or other materials in thevicinity, will lose their properties anda fire can occur.

A study has shown that a badcontact of 0,5 ohm had risen to 1 ohm after one week and to 10 ohmafter one year!

The tables below give a good indication of the amount of heat generated by bad contacts, compa-red to contacts in good condition.

Values with a good connection:

Values with a bad connection:

One of the best methods of verifying this condition, and evenvisualising it, is by carrying outthermographic controls. Thermo-graphy is a non-contact method for

measuring the temperature and isbased on the fact that every bodyemits electromagnetic radiation.

WiringThere are two types of risks:• External exposure of the cable to a

fire originating in other combusti-ble materials. The cables consist for the largest part of insulationmaterial (70 %), which means thatthere is a lot of combustion mate-rial involved.

• Or internal overheating due to over-loads or short circuits in cables.

Across the UK, there are over 9,000electrical fires each year, and morethan a third of those fires are beingcaused by inadequate or faulty wiring.A periodic inspection and testing ofthe condition of the cables could be alifesaver.

An American study revealed thatthe leading item first ignited in resi-dential electrical fires is the insulationaround electrical wires and cables(30,2%). The study showed that 38%of all deaths from fires in residentialbuildings came from insulation aroundelectrical wires.

In most cases, the fires caused bydefective or worn insulation wereclosely related to old electrical wiring.

Fires initiated by arcs can be cau-sed by short circuit arcs, due to bydefective or worn insulation, orcaused by arcs from faulty, loose or broken conductors, or from switches.

Aluminium wiring poses additionalhazards. High temperatures developat failing circuits and bad connections,which can lead to fires. Studies have shown that aluminium-wiredconnections in homes have a very highprobability of overheating comparedto copper-wired homes. A large number of connection burnouts have occurred in aluminium-wired homes,resulting in many fires involving injuries and deaths.

When is a periodic inspection needed?

It is generally accepted that anelectrical installation should be ins-pected every 10 years. In IEC 60364the 10-year interval is referred to.Unfortunately periodic inspection isnot compulsory in all countries.

When a circuit breaker trips fre-quently, or sockets or switches or fusepanels become hot or display burnmarks, an inspection and furthermaintenance is required.

Another reason to have a periodicinspection is when modifications havebeen made to old or existing installa-tions. Structural changes, or changesin the use of an installation, can impairthe safety of the installation. Anothergood reason is to have an inspectionof the electrical installation, as is donein Belgium, when there is a changeof ownership.

Curent Voltage Heat A drop, mV developed, mW

20 4 – 10 80 - 20015 3 – 8 45 - 12010 2 – 5 20 - 505 1 – 3 5 – 15

0,8 0,15 - 0,4 0,1 - 0,3

Curent Voltage Heat A drop, mV developed, mW

20 1000 – 2000 20000 - 4000015 1200 – 1400 18000 - 3600010 1500 – 3000 15000 - 300005 2000 – 4000 10000 – 20000

0,8 4000 - 7000 3000 - 5000

What to inspect?The periodic verification will

mainly take into account the follo-wing:

• Adequacy of the earthing andbonding

• Suitability of the switchgear andcontrolgear

• Serviceability of the equipment (swit-ches, socket-outlets, light fittings)by careful examination for signs ofoverheating

• The wiring system and its condition(old types of cables, insulation ofthe cables);

• Provision of RCD’s;• Presence of adequate identification

and notices;• Extent of any wear and tear, dama-

ge or other notices;• Changes in the use of the premises,

which can lead to deficiencies in theinstallation.

As during the initial verification, itis necessary to have both inspectionand tests and measurements. Themeasurements will give a good indi-cation of the status of the electricalinstallation and particularly of the cables and the contacts.

Some tests will have to be carriedout without the supply connected,whilst others can only be performedwith the installation energised.

Tests that can be carried out withthe supply connected: continuity of the protective conductors, equi-potential bonding, earth electrode resistance, earth-fault loop impedan-ce, correct operation of the RCD’s,correct operation of switches and isolators, …

Taking into account the importan-ce of the cables and contacts in anelectrical installation, the testing oftheir condition requires tests to be carried out without the supply connec-ted.

How to test the quality ofthe cables?

The most important test carried outduring the verification of an electricalinstallation is related to the verifica-tion of the insulation quality. As saidbefore, insulation deteriorates withage, some insulation will have beensubjected to mechanical wear andtear, cables might have been sub-jected to overloads, which causes excessive heat, etc…

What happens when the insulationdeteriorates? The current flowingthrough the insulation will increaseand can attain dangerous values, causing electrical shocks and fire.

The quality and the condition ofthe cables is verified by measuring theinsulation resistance.

How to measure the insulation resistance?

Principle: apply during a definedtime a stable continuous voltage, mea-sure the resulting current in betweenthe two parts under test and checkwith the ohmic law that the insula-tion resistance is higher than the minimum value required by the stan-dards.

The measurements are carried outwith an insulation tester. The insula-tion tester will be used during the

initial verification and will eliminateshirt-circuits or short to earth faults.During periodic verification, the insulation tester will help to test the integrity of the cables by revealing insulation failures, which could resultin shock and fire.

The test is made between the active conductors (phase and neutral)and the PE (protective conductor)connected to the earthing arrange-ment. For the purpose of this test, active conductors may be connectedtogether.

The dc voltage applied between thelive conductors (de-energized) and theearthing arrangement will cause a very small current to flow through theconductor and the insulation. The higher the current, the lower the resistance (R=E/I). The current will increase as insulation deteriorates.

A low insulation resistance meansthat a leakage current is flowingthrough the insulation to earth. Thisleakage current could shock an indi-vidual if there is no RCD or if there isan accidental interruption of the Protective Earth conductor. A leaka-ge current of 500 mA can generateenough heat to ignite the surroun-ding materials and this can give riseto a fire.

According to the IEC 60364-6, thefollowing table applies:

Minimal values of insulation resistanceNominal circuit voltage Test voltage d.c. Insulation resistance

V V MΩSELV and PELV 250 > 0,5

Up to and including 500 V, 500 > 1,0

including FELV

Above 500 V 1000 > 1,0

The insulation resistance, measu-red with the test voltage indicated inthe table, is satisfactory if each circuit,with the appliances disconnected, hasan insulation resistance not less than

the appropriate value given in thetable.

However, where a reading of lessthan 2 MΩ is recorded for an indivi-dual circuit, there is the possibility

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of defective insulation and it may benecessary to remedy the situation byreplacing the cable.

Costs involved The cost of the insulation tester is

not excessive and the extra timeneeded to measure the insulationresistance when carrying out a verification is small compared to the advantage of having a good picture of the quality of the electri-cal installation. Bad contacts can be remedied and bad cables can bereplaced before a fire breaks out.

Conclusions and recommendations

One must not necessarily say that all old wiring in the homes is a hazard. The main point is: what isthe condition of the cables and their insulation? Insulation becomes damaged when it is pierced or when it undergoes other mechanical damage, but also when a circuit is overloaded. The cable becomes hot and after a certain period of time, theinsulation will crack.

It is clear that a verification of anexisting electrical installation withouttesting does not go far enough to givea good indication of the state of the most important safety issue of an existing installation: the insulation quality of the cables. It will only reveal visible damage to the electricalequipment due to wear and tear and mechanical damage and, whenno test and measurements are carriedout, it could give a false sense of safety.

Therefore verification should al-ways comprise an inspection andtests.

A lot of home fires can be avoidedif the electrical installation is testedwith an insulation tester and if the cables that are not up to standard,are replaced.

To avoid the problem of badcontacts, it is a good practice to replace the cable completely when asection of a cable is damaged.

It is good practice to remove

From left to right: Deputy Minister for Electricity Mr Saleh H. Alawaji, Philippe André, Treasurer vice-president of Fisuel,

M. Saud Al Jibreen (AMAD)Riyadh Forum, 6-7 December 2010.

obsolete cables to reduce potential fire load. There is better fire perfor-mances by the new vinyl compounds,compared to that of traditional compounds

Due to the specific hazards relatedto the use of aluminium wiring, aswas used in the homes in Eastern Europe, it would be a good practice of replacing them by copper wiringat the first sign of degradation or badcontacts.

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Reproduced with the kind authorisation of ECI

� BibliographyNIEC 60364-6, Low-voltage installations –Part 6: VerificationTowards improved electrical installations inEuropean homes - European Copper Insti-tuteOverview of electrical safety in 11 countries- European Copper InstituteUS Fire Administration PublicationsESFI (Electrical Safety Foundation Interna-tional) PublicationsReducing the fire hazard in aluminium-wiredhomes J. Aronstein, Ph.D.