***Useful Information for Apprentices***

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Class 0 and 01 )

Class 0 and 01 Equipment is Allowed Only in VERY Specific Locations .
Such Equipment should NOT be Used in Normal Commercial . Industrial or Domestic Environment .for Completeness, an Explanation of these Two Types of Appliance is Included below .

Class 0 Equipment
Class 0 item of Equipment has Protection against Electric Shock that RELIES upon BASIC INSULATION Only. There is No Supplementary or Reinforced Insulation . There is ↔ No Provision for the Connection of Accessible Conductive Parts ↔ if any . to the Protective Conductor in the Fixed Wiring of the Installation . in the Event of FAILER of the BASIC Insulation Reliance is Placed Upon the Environment in which the Equipment is Installed . An Example of Class 0 Equipment is Certain Older Style Mains Powered Series-Connected Christmas Tree Lights where the Lights are Interconnected by a Bell Flex Type Cable ( Insulated but not Sheathed )

Class 01 Equipment
Class 01 item of Equipment has at Least Basic Insulation throughout . the Equipment is Provided with an EARTHING TERMINAL
The Equipment has a Power Supply Cord without a Protective Earthing Conductor . The Equipment is Fitted with a Pug without an Earthing Contact , which Cannot be Introduced into a Socket-Outlet with an Earthing Contact

Class 01 Equipment is Specialist Equipment and NOT for Common USE .

* ‘cable trunking’ means a manufactured enclosure for the protection of cables, normally of rectangular cross section,
* ‘circuit breaker’ means a mechanical switching device capable of making, carrying and breaking currents under normal circuit conditions and also of making, carrying for a specified time, and breaking currents under specified abnormal circuit conditions, such as those of short circuit.
* ‘circuit protective conductor’ means a protective conductor connecting exposed conductive parts of equipment to the main earthing terminal.
* ‘connector’ means a device which is provided with female contacts and is intended to be attached to the flexible cable connected to the supply.
* ‘danger’ means a risk of bodily injury or loss of life or health from shock, burn, asphyxiation or other causes.
* ‘duct’ means a closed passage way formed underground or in a structure and intended to receive one or more cables which may be drawn in.
* ‘earth electrode resistance’ means the resistance of an earth electrode to earth.
‘earth fault loop impedance’ means the impedance of the earth fault current loop (phase to earth loop) starting and ending at the point of earth fault.
* ‘earthed’ means connected to the general mass of earth in such a manner as will ensure at all times an immediate discharge of electrical energy without danger; when applied to electrical equipment, all phases short-circuited and effectively connected to earth.
* ‘earthing conductor’ means a protective conductor connecting a main earthing terminal of an installation to an earth electrode or to other means of earthing.
* ‘enclosure’ means a part providing an appropriate degree of protection of equipment against certain external influences and a defined degree of protection against contact with live parts from any direction.
* ‘equipment’ means electrical equipment. ‘equipotential bonding’ means electrical connection putting various exposed conductive parts and extraneous conductive parts at a substantially equal potential.
( 17th Edition ↔ Main Protective Bonding Conductor ↔ Old 16th Edition equipotential bonding’ ) if you are Not Sure Look up p/32 Regs
‘extra low voltage’ means voltage normally not exceeding 50Vroot mean square alternating current or 120V direct current, between conductors or between a conductor and earth. ( Regs p/31 )
* ‘fault protection’ means protection against dangers that may arise from indirect contact with live parts of the installation (contact with an exposed conductive part that is not normally live but has become live under fault conditions).
* ‘high voltage’ means voltage normally exceeding low voltage. ‘H.V. enclosure’ means a substation, standby generator house, distribution centre and a room or other enclosure wherein high voltage apparatus is installed. “Danger” notice shall be permanently affixed outside H.V. enclosure access doors.
* ‘installation’ means electrical installation.
* ‘live’ means electrically charged.
* ‘live work’ means electrical work on or near any live conductor. This is anywhere a worker is exposed to energised conductors, terminals, busbars or contacts.
* ( Regs Part 1 p/12 ) ↔ ‘low voltage’ means voltage normally exceeding extra low voltage but normally not exceeding: between conductors, 1000V root mean square alternating current or 1500V direct current, or between a conductor and earth, 600V root mean square alternating current or 900V direct current. ( Regs / Part 2 /Definitions ↔ p-31 ) **** ( Frequencies 50Hz , 60Hz , 400Hz ) -&-s
* ‘overhead line’ is defined in the Electricity (Wiring) Regulations as a conductor that is placed above ground and is suspended in the open air.
* ‘PELV (Protective Extra-Low Voltage)’ means an extra-low voltage system which is not electrically separated from earth, but which otherwise satisfies all the requirements for SELV.
* ‘permit-to-work’ means an official form signed and issued by a responsible person to a person having the permission of the responsible person in charge of work to be carried out on any earthed electrical equipment for the purpose of making known to such person exactly what electrical equipment is dead, isolated from all live conductors, has been discharged, is connected to earth, and on which it is safe to work.
* ‘powertrack system’ means an assembly of system components including a generally linear assembly of spaced and supported busbars by which accessories may be connected to an electrical supply at one or more points(pre-determined or otherwise) along the powertrack.
* ‘protective conductor’ means a conductor used for some measures of protection against electric shock and intended for connecting together any of the following parts :-
(i) exposed conductive parts,
(ii) extraneous conductive parts,
(iii) main earthing terminal,
(iv) earth electrode(s),
(v) the earthed point of the source, or an artificial neutral.

( Type of Protective Conductor : 543.2.1 . A Gas/Pipe ,an Oil/Pipe, Flexible or Pliable Conduit , Support/Wires or Other Flexible Metallic Parts , or Constructional Parts subject to Mechanical Stress in Normal Service , shall NOT be Selected as a Protective Conductor )

* ‘residual operating current’ means residual current which causes the residual current device to operate under specified conditions.
* ‘restrictive conductive location’ means a location comprised mainly of metallic or conductive surrounding parts, within which it is likely that a person will come into contact through a substantial portion of their body with the conductive surrounding parts and where the possibility of preventing this contact is limited.
* ‘rising mains’ means that part of the installation which is used for distribution of electricity throughout any building normally used for multiple occupation. ‘screen’ means an effective means of identifying or shielding the safe working area from a source of danger.
* ‘SELV’ (Separated Extra-Low Voltage) means an extra-low voltage which is electrically separated from earth and from other systems in such a way that single fault cannot give rise to the risk of electric shock.
* ‘short circuit current’ means an overcurrent resulting from a fault of negligible impedance between live conductors having a difference in potential under normal operating conditions.
* ‘socket outlet’ means a device, provided with female contacts, which is intended to be installed with the fixed wiring, and intended to receive a plug.

Take for example, wall-mounted socket-outlets and switches. They now have to be installed 450 to 1200 mm above the floor in dwellings, and 400 to 1400 mm in buildings other than dwellings. As such, they are far more visible than ever before, undergone a Part M makeover.

RCD - now ( virtually ) mandatory in homes.

Whilst residual current devices RCD have been in use for many years, the new 17th Edition requires electricians to consider the use of RCDs in many more applications than the current standard requires in order to improve building protection.

The basic function of an RCD is to trip and disconnect the supply of electricity in the event of an earth fault in order to prevent electric shock and fire risk. It does this by detecting the imbalance of currents between the live and neutral lines caused by a fault to earth. Drawing attention to the importance of using RCDs in the right context and with the right equipment, the IEE Wiring Regulations provides guidance on how RCDs should be incorporated in new builds.

30mA RCD protection for ALL sockets:

Additionally, all socket outlets rated at 20A or below within a domestic building will require 30mA RCD protection*. This means that all ring main circuits from consumer units will either need to be fed from the RCD side of a traditional split load board or have individual residual current breakers with overload ( RCBO ) ways.

Because the RCD is sensitive to current imbalances, it is not practical to fit just one device to protect an entire house. If a fault develops within one circuit, all circuits would be switched off immediately. By using individual and grouped RCD protected ways in combination with one another, the required protection can be provided whilst maintaining continuity of supply to other non-affected zones within the installation

 

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How our guides will help you
The 17th Edition changes mean that all commercial, domestic and industrial wiring installations must be designed, constructed, inspected, tested and certified to meet the requirements of BS 7671: 2008. designed,

Who are our 17th Edition guides intended for?
Whether you work in the residential or commercial sectors, these 17th edition guides will provide you with expert information and help you to overcome certain issues to ensure your work meets the required standard.

Protection for Safety

Part 4, chapters 41 to 45 Describes the various measures that are available to the installer and designer for the protection of people, property and livestock against Electric Shock, different definitions are now used for the 17th edition BS7671;2008.
Residential Requirements Example :- The electrical system should be designed and installed so that live parts shall not be accessible and accessible conductive parts should not cause a hazard to the user. What it means ? Various measures can be employed to protect the users, shielding the live parts with enclosures and insulation are the most common. Additional protection is normally provided with Residual Current Devices. Solution : ( Insulating the whole system and providing automatic disconnection of the supply definitions are now ) * Basic protection (enclosures, insulation) * Fault protection (disconnection with mcb’s) * Additional protection (RCD) where needed

Commercial Requirements Example :- The electrical system should be designed and installed so that live parts shall not be accessible and accessible conductive parts should not cause a hazard to the user. What it means ? Various measures can be employed to protect the users, shielding the live parts with enclosures and insulation are the most common. Additional protection is normally provided with Residual Current Devices. Solution : ( Insulating the whole system and providing automatic disconnection of the supply definitions are now ) * Basic protection (enclosures, insulation) * Fault protection (disconnection with mcb’s) * Additional protection (RCD) where needed

Assessment of General Characteristics

Part 3, chapters 31 to 35 : This requires the designer and installer to make an assessment on the purpose for which the installation is to be used, any external influences which may affect the installation, continuity of service and the maintainability and compatibility of equipment.
Residential Requirements : Example :-
( The installer must consider the use of the property and any special requirements of the users )
What it means :-
( The needs of the occupier should be assessed for each property, layout and use will be different for an apartment or detached house )
Solution :-
( Arrange the installation and equipment to suit the needs of the occupier and split circuits so that a fault on one circuit causes the minimum amount of problems )
Commercial Requirements : Example :-
( For the life of the installation, the design needs to cover the changing needs of the user in layout and loading )
What it means :-
( Commercial properties may have a need to change requirements on a regular basis, the installation needs to be able to cope with these changes. Regular maintenance requirements should also be considered )
Solution :-
( Circuits such as ring mains need to be designed and split to ensure continuity of service and minimum disruption to the business in the event of a fault. The use of RCBO’s for individual circuits is recommended vs grouping )

Selection and Erection of Equipment :

Part 5, chapters 51 to 56 This part provides common rules for compliance with protection measures for safety.
Residential Requirements : Example :-
Installation will conform to the requirements of the regulations including cables concealed in walls.

What it means :-
Since cables are concealed the standard gives a number of measures in 522.6.6 which are designed to protect the user from inadvertently causing a fault.

Solution :-
A variety of solutions are shown for cables concealed in walls, if the cable is mechanically protected and within the zones stated residual current protection is not required. It may be required to meet another part of the standard though.

Commercial Requirements Example :-
Installation will conform to the requirements of the regulations including cables concealed in walls, the requirements for partition walls are more exacting if they are constructed from a metallic frame.

What it means :-
Since cables are concealed the standard gives a number of measures in 522.6.6 which are designed to protect the user from inadvertently causing a fault.

Solution :-
A variety of solutions are shown for cables concealed in walls, if the cable is mechanically protected and within the zones stated residual current protection is not required. It may be required to meet another part of the standard though and if the wall is constructed using metallic parts may be the most cost effective solution.

 

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Inspection and testing :

Part 6, chapters 61 to 63 During testing, to ensure the regulation has been complied with, precautions shall be taken to avoid danger to persons, property and installed equipment.
Residential Requirements , Example :-
The requirement for full inspection and testing has not changed, this should be carried out safely and by a skilled person. However, some details have changed and need to fully understood by the inspector.

What it means ?
Changes have been introduced such as: Inspection and testing is now known as table 61. Regs – p/158
Minimum installation values changed to: * 0.5 MΩ Selv or Pelv at 250 d.c. volts ) * 1.0 MΩ for systems up to and including 500 d.c. volts with a test voltage of 500 volts. * For systems above 500 volts :- tested at 1000 volts the minimum is also 1.0 MΩ
Solution
Only a skilled person competent in such work should be used to conduct the inspection and testing. Proof of competence should be shown.
Commercial Requirements : Example :-
The requirement for full inspection and testing has not changed, this should be carried out safely and by a skilled person. However, some details have changed and need to fully understood by the inspector. What it means ?
Changes have been introduced such as:
Inspection and testing , is now known as table 61.

Minimum installation values changed to:- * 0.5 MΩ Selv or Pelv at 250 volts * 1.0 MΩ for systems up to and including 500 volts with a test voltage of 500 volts. * For systems above 500 volts :- tested at 1000 volts the minimum is also 1.0 MΩ

Solution :-
Only a skilled person competent in such work should be used to conduct the inspection and testing. Proof of competence should be shown.

Special Installations :

Part 7, sections 700 to 712,717,721,740,753 A number of special locations are detailed which have further requirements than listed in the general 17th edition. They vary from a location containing a bath or shower, to floor and ceiling heating systems.
Residential Requirements ,
Example :
In areas that can have an extra risk for people, additional protection will be required, generally in the form of residual current devices. However other means can be employed in certain instances.

What it means ?
In any location which contains a bath or shower, sauna or swimming pool, the effects of electric shock on a person could well be magnified by up to 25%, so additional protection is required in these locations.

Solution :
Supplies into these locations should be protected by 30mA Residual Current Devices, either RCCB or RCBO and must be circuits arranged to minimise the effects on other circuits if devices operates.
Commercial Requirements :
Example :
In areas which can have an extra risk for people additional protection will be required, generally in the form of residual current devices. However other means can be employed in certain instances.

What it means ?
The same measures for residential apply to the commercial market. If there is an extra risk to persons, then additional protection must be employed, for instance in agricultural premises.

Solution :
Part 7 will detail the sensitivity of additional protection for the various locations which include construction or demolition sites, marinas and exhibitions. Circuits should be arranged to minimise disruption in the event of a fault operating a protection device.

A fundamental
A fundamental principle is that the point of isolation should be under the control of the person who is carrying out the work on the isolated conductors.

 

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Regulatory Requirements :
(Stat & Non-Stat ( Elec )

Statutory Regulations

The following regulations have been passed as statutory regulations and as such must be obeyed. They are as such mandatory.

Health & Safety at Work Act 1974 :
Has wide use in the industry and when undertaking inspection & testing you have specific duties for the safety of yourself and others under this act ;

Electricity Safety, Quality & Continuity Regulations 2002 :
These Regulations specify power quality and supply continuity requirements to ensure an efficient and economic supply for customers)

Statutory Regs cont’d :
Electricity at Work Regulations 1989 ;
consists of a series of regulations some absolute some reasonably practical. Every employer or self employed person has a duty to conform to these mandatory regulations. The level of responsibility you hold to make sure the regulations are met depends on the amount of control you have over electrical safety in any particular situation).

* In terms of carrying out inspection and testing on an installation your title in law is that of ‘Duty Holder’ since you will typically exercise
full control over the installation under test.
* Your legal status must be that of ‘Competent Person’.

Non-Statutory Regulations :
* IEE Wiring Regulations (BS7671:2008)
These regulations represent a good practice document and are a standard towards which the industry should carry out their work in the field. However, despite the ‘non-mandatory’ nature of BS7671 it is backed by the EAWR 1989 and an electrical installation which complies
with the current edition of the IEE Wiring Regulations is viewed by the HSE as likely to achieve conformity with the relevant parts of EAWR 1989.
* Since BS7671 falls into the area of being ‘non-statutory’,
it follows that supportive booklets such as the On Site Guide and Guidance Note 3 are similar non-mandatory documents.

General Requirements for Inspection & Testing :
* Reg 610.1 (BS7671:2008) States:-
Every installation shall, during erection and on completion before being put into service, be inspected and tested to verify, so far as is reasonably practicable, that the requirements of the regulations have been met.

* This is backed up by EAWR regulation 4 which states :
All electrical systems shall be constructed and maintained to prevent danger.

General Requirements cont’d
* The reason for an inspection and test therefore is to verify that the installation complies with the regulations with regard to its design and construction.
* Similarly regulation 610.4 states:-
* For an addition or alteration to an existing installation, it shall be verified that the addition or alteration complies with the regulations and does not impair the safety of the existing installation.

* And Regulation 621.1 states:-
Where required, periodic inspection and testing of every electrical installation shall be carried out in accordance with regulations 621.2
to 621.5.

Senses :
* It is important to realise that when undertaking the inspection process the senses used to make informed judgements regarding the condition of the installation are those of :-

* Sight
* Touch
* Smell











[FONT=Comic+Sans+MS+Bold0]Continuity of Circuit Protective Conductors ( CPC[FONT=Comic+Sans+MS+Bold1252]’[/FONT][FONT=Comic+Sans+MS+Bold0]s [/FONT][FONT=Comic+Sans+MS0]) [/FONT][/FONT]
[FONT=Comic+Sans+MS0] [/FONT]
 [FONT=Comic+Sans+MS0]Dead Test[/FONT]
 [FONT=Comic+Sans+MS0]Involves testing the continuity of cpc[FONT=Comic+Sans+MS1252]’[/FONT][FONT=Comic+Sans+MS0]s, main equipotential bonding conductors and any supplememtary bonding conductors.[/FONT][/FONT]
[FONT=Comic+Sans+MS0] [/FONT]
 [FONT=Comic+Sans+MS0]Use a [FONT=Comic+Sans+MS1252]‘[/FONT][FONT=Comic+Sans+MS0]Low Ohm Meter[/FONT][FONT=Comic+Sans+MS1252]’[/FONT][FONT=Comic+Sans+MS0].[/FONT][/FONT]
 [FONT=Comic+Sans+MS0]In order to provide protection against electric shock using automatic disconnection of supply, each point and accessory within the installation should incorporate a cpc connected to earth. (Exception made for lampholder with no exposed parts connected to such a point).[/FONT]
 [FONT=Comic+Sans+MS0]Such a test ensures conductors are electrically sound and correctly connected.[/FONT]
 [FONT=Comic+Sans+MS0]Due to the existence of parallel paths it is only simple in all insulated circuits. If other systems of wiring are utilised ( conduit/trunking ) this test should be carried out at stages during construction such that parallel paths are not in place when testing.[/FONT]
 [FONT=Comic+Sans+MS0]Two methods may be adopted for this test but it is important to note that when testing the continuity of cpc[FONT=Comic+Sans+MS1252]’[/FONT][FONT=Comic+Sans+MS0]s with respect to supplementary bonding and equipotential bonding conductors that in order to avoid parallel paths it is necessary to disconnect one end of the conductor in each case to obtain an accurate value. [/FONT][/FONT]
[FONT=Comic+Sans+MS0] [/FONT]
**  [FONT=Comic+Sans+MS0]Test method 1 will yield (R1+R2) for the circuit whilst test method 2 will yield the R2 value.[/FONT]
[FONT=Comic+Sans+MS0] [/FONT]
[FONT=Comic+Sans+MS0] [/FONT]

[FONT=Comic+Sans+MS0]Sorry “ Dan “ I don’t know how to adjust the setting on my Comp ( Help are they are sites I can go onto about Windows Vista Ultimate ) to Help Me !!!!!!! Top Quality Rubbish . Amberleaf [/FONT]

 

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[FONT=Comic+Sans+MS+Bold0]Continuity of Ring Final Circuit conductors [/FONT]
 [FONT=Comic+Sans+MS0]Dead Test[/FONT]
 [FONT=Comic+Sans+MS0]Involves ensuring cpc is continuous and connected to each outlet, there are no interconnections, and to verify polarity.[/FONT]
 [FONT=Comic+Sans+MS0]Use a [FONT=Comic+Sans+MS1252]‘[/FONT][FONT=Comic+Sans+MS0]Low Ohm Meter[/FONT][FONT=Comic+Sans+MS1252]’[/FONT][FONT=Comic+Sans+MS0].[/FONT][/FONT]
 [FONT=Comic+Sans+MS0]It is a three step test :-[/FONT]
* [FONT=Comic+Sans+MS0]End to end resistance measurements are made of phase, neutral, cpc yielding ( r1 ↔ Line , r2 Earth , rN , Neutral values.[/FONT]
* [FONT=Comic+Sans+MS0]Cross couple phase and neutral conductors and measure resistance at each socket outlet and the origin. All readings on a full ring should be substantially the same. ←←←← ** [/FONT]
* [FONT=Comic+Sans+MS0]Cross couple phase and cpc conductors and measure resistance at each socket outlet and the origin. All readings on a full ring should be substantially the same. The highest recorded value is the value of ( R1+R2 ) for the circuit.[/FONT]
[FONT=Comic+Sans+MS0] [/FONT]

[FONT=Comic+Sans+MS+Bold0]Earth Fault Loop Impedance ( Zs ) [/FONT]
* [FONT=Comic+Sans+MS0]This is a live test[/FONT]
* [FONT=Comic+Sans+MS0]Can be obtained by direct measurement using an [FONT=Comic+Sans+MS1252]‘[/FONT][FONT=Comic+Sans+MS0]Earth Loop Impedance measuring instrument[/FONT][FONT=Comic+Sans+MS1252]’[/FONT][FONT=Comic+Sans+MS0]. Or by adding ( R1 +R2 ) obtained earlier to Ze.[/FONT][/FONT]

[FONT=Comic+Sans+MS+Bold0]Obtaining Ze (External loop impedance)[/FONT]
* [FONT=Comic+Sans+MS0]By measurement[/FONT]
* [FONT=Comic+Sans+MS0]By Enquiry (Must test to ensure earth is present)[/FONT]
* [FONT=Comic+Sans+MS0]By Calculation[/FONT]
[FONT=Comic+Sans+MS0]By measurement (Undertaken in order to prove an earth connection and to ensure value of ( Ze) is in line with designers intentions).[/FONT]
* [FONT=Comic+Sans+MS0]Test made at the source of supply between the phase and means of earthing with the means of earthing disconnected from the installation. This entails isolating the installation.[/FONT]
* [FONT=Comic+Sans+MS0]This should yield a value that in combination with ( R1+R2 ) ensures an appropriate value of ( Zs ) for all circuits.[/FONT]

[FONT=Comic+Sans+MS0]Supply authorities quote typical values of Ze for the following systems :-[/FONT]
* [FONT=Comic+Sans+MS0]TN-S : 0.8[FONT=Comic+Sans+MS0]Ω[/FONT][/FONT]
* [FONT=Comic+Sans+MS0]TN-C-S : 0.35[FONT=Comic+Sans+MS0]Ω[/FONT][/FONT]
* [FONT=Comic+Sans+MS0]TT : 21[FONT=Comic+Sans+MS0]Ω[/FONT][/FONT]

[FONT=Comic+Sans+MS+Bold0]Voltage Drop: [/FONT]

[FONT=Comic+Sans+MS0]Volt drop should be such that it does not impair the safe functioning of installed equipment.[/FONT]
[FONT=Comic+Sans+MS0]Typically it will be evaluated (not measured) using the measured circuit impedance. ( In practice this calculation must also take on details of the load impedance ).[/FONT]

 

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[FONT=Comic+Sans+MS0]Are these Regulations Statutory ? [/FONT]
[FONT=Comic+Sans+MS0]No , but they can be Used as Evidence of Compliance with Statutory Regulations ( Regs 114.1 ) [/FONT]

[FONT=Comic+Sans+MS0]( Limited Value within the Domestic Installation in Terms of Enforcement ) [/FONT]

[FONT=Comic+Sans+MS0]Very few Enforceable Regulations Apply to Domestic installations [/FONT]

[FONT=Comic+Sans+MS0]* The Commercial or Industrial Electrical Installation usually Under the Control of Competent Persons . [/FONT]
[FONT=Comic+Sans+MS0]* Statutory Measures in Place to ensure a Safe Working Environment :- [/FONT]
[FONT=Comic+Sans+MS0]This includes the Electrical Installation and Electrical Equipment [/FONT]

[FONT=Comic+Sans+MS0]* Failure to Comply with Statutory Regulations within the Workplace can Lead to Criminal Prosecution . [/FONT]

[FONT=Comic+Sans+MS0]> What happens if an Electrical Contractor carries Out Work in an Unsatisfactory Manner ? [/FONT]
[FONT=Comic+Sans+MS0]If the Contractors are Members of the NICEIC , then Appropriate Action can be Taken [/FONT]

[FONT=Comic+Sans+MS0]If Not , the Trading Standards Office , or Local Authority may be Able to Help .[/FONT]

[FONT=Comic+Sans+MS0]With many Domestic Installations there is Little or No Maintenance Undertaken to Ensure Continued Safety [/FONT]
[FONT=Comic+Sans+MS0]( in Many Cases , the Integrity and Safety of the Installation is Reduced by the DIY . Person ) [/FONT]

[FONT=Comic+Sans+MS0]The Need for Inspection and Testing : [/FONT]

[FONT=Comic+Sans+MS0]Installations should be Inspected and Tested :- [/FONT]
[FONT=Comic+Sans+MS0]* Before being put into Service – ( Initial Verification ) [/FONT]
[FONT=Comic+Sans+MS0]* at Regular Intervals thereafter – ( Periodic ) [/FONT]
[FONT=Comic+Sans+MS0]* On Completion of Any Alterations or Additions [/FONT]

[FONT=Comic+Sans+MS0]Initial Verification : [/FONT]
[FONT=Comic+Sans+MS0]For an Initial Verification : BS-7671:2008 states[/FONT]
[FONT=Comic+Sans+MS0]* Installed Equipment to an Appropriate Standard i.e. ( BS / BS-EN etc ↔ Regs 133.1.1 / 133.1.2 / 133.1.3 )[/FONT]
[FONT=Comic+Sans+MS0]* Correctly Selected and Erected . [/FONT]
[FONT=Comic+Sans+MS0]* Not Visibly Damaged or Defective as to Impair Safety .[/FONT]

[FONT=Comic+Sans+MS0]The Periodic Installation Inspection : [/FONT]
[FONT=Comic+Sans+MS0]BS-7671:2008 states , [/FONT]
[FONT=Comic+Sans+MS0]Periodic Inspection and Testing of an Electrical Installation shall be Carried out to Determine , so far as is Reasonably Practicable , whether the Installation is in a Satisfactory Condition for Continued Service .[/FONT]

[FONT=Comic+Sans+MS0]>> Generally , the Main Reason for Undertaking an Inspection and Test is to Ensure that the Installation is Safe to Use , [/FONT]

[FONT=Comic+Sans+MS0]What are the Likely Reasons for an Installation Failing to be Safe ????? [/FONT]
[FONT=Comic+Sans+MS0]* Age [/FONT]
[FONT=Comic+Sans+MS0]* Wear and Tear – May be Considerable in Rented Accommodation [/FONT]
[FONT=Comic+Sans+MS0]> Botched Work by Incompetent Persons , or Unscrupulous Contractors .[/FONT]

[FONT=Comic+Sans+MS0]1) Factors Affecting the Safety ( Some Common Factors will Include :- [/FONT]
[FONT=Comic+Sans+MS0]* Damage to Equipment or Accessories [/FONT]
[FONT=Comic+Sans+MS0]* Poorly Installed Equipment/ Accessories [/FONT]
[FONT=Comic+Sans+MS0]* Loose Connections given Rise to Shock/Fire [/FONT]
[FONT=Comic+Sans+MS0]* Overloaded Circuits [/FONT]
[FONT=Comic+Sans+MS0]* Inadequate Protection of Circuits against Overcurrent [/FONT]
[FONT=Comic+Sans+MS0]* Circuit Cables Inadequate to Safety carry Load Current [/FONT]
[FONT=Comic+Sans+MS0]* Inadequate Earthing Arrangements [/FONT]

[FONT=Comic+Sans+MS0]The Visual Inspection : [/FONT]
[FONT=Comic+Sans+MS0]For Reasons of Safety the Supply should Preferably be Switched OFF Prior to Conducting the Inspection [/FONT]

[FONT=Comic+Sans+MS0]> ( Loose Connections may Result in ) :- [/FONT]
[FONT=Comic+Sans+MS0]Electric Shock / Fire [/FONT]
[FONT=Comic+Sans+MS0]Circuit Connections may be Dislodged by Movement of the Socket-Outlet .[/FONT]
[FONT=Comic+Sans+MS0]( Remember to :- All Terminations should be Checked before Socket is Secured ) ←←← [/FONT]

 

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Isolate :

N.B. simply switching something off is not the same as isolating. Switching may well break the normal load current whereas isolating will cut the already dead circuit so that re-closing the switch will not make it live again.

Test the Equipment and System is Dead :

All circuits to be worked on must be tested to ensure they are dead. The voltage indicator or test lamp must first be tested on a known supply or proving unit before use. Then test between phase and neutral, phase and earth then neutral and earth. Three phase supplies will be tested between all phases, between phases and earth and between phases and neutral and neutral and earth,
providing a neutral is included in the circuit. After testing retest the indicator to prove it is not faulty and also erect warning notices clearly stating [FONT=Arial+Bold1252]“ [/FONT]Danger Electrician at Work [FONT=Arial+Bold1252]”[/FONT].

N.B. All live conductors must be isolated before work can be done. As the neutral conductor is classified as a live conductor this also has to be disconnected.

Electricians must be on guard, as you may have no idea what type of supply you will be working on.

* Identify sources of supply
* Isolate
* Secure isolation
* Test that the equipment/system is dead
* Begin work

[FONT=Arial+Black0]GS38 : [/FONT]

GS38 is a guidance document produced by the Health & Safety Executive dealing with electrical test equipment.
* In particular it states that test leads must satisfy certain criteria in order to comply with GS38.
* Under GS38 test leads, used to measure or apply voltages

Fused leads
shrouded connectors
finger barriers ↔ ( Finger Guards )
identifiable leads
insulated flexible and robust leads
minimum of 4mm exposed tip ( recommended 2mm, spring loaded ) ↔ ( 2-4 of Tip )
I

 

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System
An electrical system in which all the electrical equipment is, or may be electrically connected to a common source of electrical energy and includes such source and such equipment

PME System: Regs p/33
An earthing arrangement, found in TN-C-S systems, in which the supply neutral conductor is used to connect the earthing conductor of an installation with Earth, in accordance with ESQCR 2002

TN-S System : Regs p/33
A system having separate neutral and protective conductors throughout the system

TN-C-S System : Regs p/33
A system in which neutral and protective functions are combined in a single conductor in part of the system

TT System : Regs p/34
A system having one point of the source of energy directly earthed, the exposed-conductive parts of the installation being connected to earth electrodes electrically independent of the earth electrodes of the source

Low Voltage ( Regs p/31 )
Exceeding 50 V a.c. or 120 V ripple-free d.c., whether between conductors or to Earth but not exceeding 1000 V a.c. or 1500 V d.c. between conductors, or 600 V a.c. or 900 V between conductors and Earth

High Voltage
Normally exceeding Low Voltage

Fixed Equipment ( Definitions p/24 )
Equipment designed to be fastened to a support or otherwise secured in a specific location

Electrical Equipment ( Definitions p/23 )
Any item for such purposes as generation, conversion, transmission, distribution or utilisation of electrical energy, such as machines, transformers, apparatus, measuring instruments, protective devices, wiring systems, accessories, appliances and luminaires

Electrical Appliance
An item of current-using equipment other than a luminaire or an independent motor

Danger ( Definitions p/22 )
Risk of injury to persons (and livestock where expected to be present) from fire, electric shock, burns, arcing and explosion arising from use of electrical energy, and mechanical movement

( If in doubt look up the Regulations ↔ Definitions ) if you are sitting your 17th Edition .

** Mandatory Compliance is defined as :
The Compliance with any Departmental mandated regulation applicable to the infrastructure.

STATUTORY COMPLIANCE
Statutory Compliance is understood and agreed to be:-
Compliance with any Act or Regulation applicable to the infrastructure.

A Problem with many Installations , Particularly Domestic , is that ↔ Every Man and his Dog has had a Hand in it

The domestic electrical installation
* likely to have been originally installed by competent electrical contractor
* additions/alterations possibly undertaken by unqualified persons
* periodic inspection and testing to ensure continued safety is unlikely

To what standards should an electrical installation conform ?
The Institution of Electrical Engineers Wiring Regulations

Are these regulations statutory? ( IEE Wiring Regulations BS-7671:2008 )
No, but they can be used as evidence of compliance with statutory regulations

* limited value within the domestic installation in terms of enforcement
Very few enforceable regulations apply to domestic installations

* The commercial or industrial electrical installation usually under the control of competent persons.
* Statutory measures in place to ensure a safe working environment. This includes the electrical installation and electrical equipment
* Failure to comply with statutory regulations within the workplace can lead to criminal prosecution

Other Interested Parties
Two organisations concerned with the quality and safety of all aspects of electrical installation work in including domestic

The Electrical Contractors AssociationE.C.A.
National Inspection Council for Electrical Installation Contracting N.I.C.E.I.C.

Organisations only concerned with the competence and quality of work for those electrical contractors who are members of their organisation

The need for Inspection and Test
Installations should be inspected and tested
* before being put into service - (initial verification)
* at regular intervals thereafter - (periodic)
* on completion of any alterations or additions

The Initial Verification
For an initial verification
BS 7671:2001 states:
* installed equipment to an appropriate standard, i.e. BS, BS EN etc.
* correctly selected and erected
* not visibly damaged or defective as to impair safety

The periodic installation inspection
BS 7671:2001 states
Periodic inspection and testing of an electrical installation shall be carried out to determine, so far as is reasonably practicable, whether the installation is in a satisfactory condition for continued service

Generally, the main reason for undertaking an inspection and test is to ensure that the installation is safe to use

What are the likely reasons for an installation failing to be safe ?
* Age
* Wear and tear - may be considerable in rented accommodation
* Botched work by incompetent persons, or unscrupulous contractors

Generally, the main reason for undertaking an inspection and test is to ensure that the installation is safe to use

Periodic Inspection Report
Where is it required ?
* expiry of current certificate
* change of ownership or use
* as a result of damage - flood, fire, etc
* mortgage/insurance purposes

Damage to equipment or accessories
Poorly installed equipment/accessories
Loose connections giving rise to shock/fire
Overloaded circuits
Inadequate protection of circuits against overcurrent
Circuit cables inadequate to safely carry load current
Inadequate earthing arrangements

Factors affecting the safety some common factors will include :-

 

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Just back from a house , New 12Way M- box Split load ( small time Reading ) the lady had a broken D/light bulb , asked me to have a look at it ?
As you do just nip down Trip the RCD . would not Trip ( Faulty ) . the good news is that the Bathroom has Supplementary Equipotential Bonding 10mm2 Cross-Bonded

411.3.2.6
Where Automatic Disconnection according to Regulation 411.3.2.1 cannot be Achieved in the Time Required by Regulation 411.3.2.2 / 411.3.2.3 or 411.3.2.4 , as appropriate , Supplementary Equipotential Bonding shall be provided in Accordance with Regulation 415.2

Residual Current Device ( RCD ) a Mechanical switching device or association of devices intended to cause the opening of the contacts when the Residual Current attains a given Value Under Specified Conditions .
( RCD ) : Offers ↔ Protection Against Earth Fault Current ←←←
So the point is that in a Court of Law the RCD would not go out in 0.4Secs ( Relying on the MCB ) Under Fault Conditions
Do Not Always rely on a RCD .
If I went just for the MCB .( How long would the User find out she had a Faulty RCD ? Cover you But at all Times : Regulations !!!!!


Carried out at the Main Switch to ensure the Incoming supply has not been reversed
PH-N - 230v
PH.E- 230v
N - E - 0v ******* A Must

Name of Test : Continuity of CPC
Instrument : Low Résistance Ohmeter
Scale : Low Ohms
Max/Min Reading : Low Ohms
Any Other Info : Link PH & CPC at DB, and take reading at furthest point - This is called the ( R1 + R2 ) Value

PSC :
Lower than the breaking Capacity of the Device before it :
Expected Reading :-
The Lower the Ze the higher the PSC as PSC = Uo/Ze
Any Other Info : PSCC & PEFC are different - PSCC is generally higher than PEFC due to the larger csa of the PH & N as opposed to the PH & E.

Standard UK Electrical Supplies :
Single Phase – 230volt 50Hz
Three Phase – 400 volt 50Hz

Choose your Light Bulb by the Type of Fitting , Bayonet , GLS. ( with Two Small Pins ) or Screw Thread ,
Next choose the light intensity by the wattage, (W).
* GU10 LIGHT FITTINGS HAVE TWO SMALL ROUND PINS AND ARE MAINS SUPPLIED 230V * MR16 DICHROIC LIGHT FITTINGS ARE LOW VOLTAGE 12V AC AND HAVE TWO SMALL PINS

Step One – Identify your Switches ;

Two-Way switches have three-terminals at the back . L1 / L2 and Common ( sometimes L )
One-Way switches have two-terminals at the back . L and L1
Three-Way switches is rare in Domestic houses and Uses . three light switches for One Light Fitting
( 3-Wire switches use Three-Core and Earth Cable between the switches ,
( 2-Wire switches use Two-Core and Earth Cable between the switches , ( Switch Live / Permanent Live )

Remember the following with Cooker Circuits ,
1) No other Circuits may be added or Spured off a Cooker . Unless it is Another Cooker in the Same Room .
2) The Circuit Breaker must be Calculated Using Diversity and Maximum Demand for this Calculation .
2) A Socket Outlet may Only be Used if Incorporated in to the Cooker Outlet.
3) Cooker control units should ideally be within ( 2m ) of the Cooker or Hob, but strictly Not above it.
4) Circuit Breakers of 30A, 32A and 40A are typical.
5) No Cooker, Oven or Hob over ( 2Kw ) may be Connected to a Ring Circuit, it must be on a Dedicated Radial Supply.

* How to Select your Dimmer Switch :
1) Make sure all the lights on the circuit are all the same. Add up all of the power ratings in Watts (VA), i.e. 6 x 50W = 300W 2) Choose a dimmer switch with rating the next size up from the total power you calculated in step 1.
3) Choose a dimmer with 1 knob (gang) for each circuit. Select 1 way or 2 way operation, if in doubt select two way, which can be used as a one way as well.
3) Make sure the dimmer will work on your type of lamp. Florescent dimmers are specials, also some low voltage transformers are not dimmable. There is also a minimum Wattage that each dimmer will work on.

PT :
Where a fault is identified during either type of examination, the item of faulty equipment must be immediately taken out of service and labelled to indicate that the equipment must not be used ( DO NOT USE - Equipment Faulty )

Research into long-term reliability of RCD protection devices !!!!!

* The mechanisms by which RCDs fail to operate correctly after prolonged periods of inactivity in domestic environments.

it was concluded that:-
Previous research published in Italy indicated that electromechanical RCDs had an average failure rate of 7.1%. However, if the RCDs were operated regularly by means of the integral test button, this figure fell to 2.8%, indicating that RCD reliability improved if they had been operated regularly. ( The User )

From the available evidence, the primary mode of failure on electro-mechanical RCDs was ingress of fine particles of dust and moisture causing the moving components to stick or to operate slower than intended.

 

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This is Something I knocked Up

Where:
( Ze ) is the external earth fault loop impedance in ohms (Ω)
Total Impedance Zs = Ze + ( R1 + R2 )

Typical values based on a 100A service are:
TN-S system 0.8 Ω
TN-C-S system 0.35 Ω

R1 The Résistance of the finalcircuit Line Conductor
R2 The Résistance of the finalcircuit Protective Conductor

Unit of measurement, the ( Ω ) Ohms .
Calculations :
A circuit is wired in pvc multicore 70°C sheath (thermoplastic) with copper conductors having phase and cpc sizes of 2.5/1.0mm2 respectively.
The length of circuit is 30 metres and protection is by a 20A BS 88 cartridge fuse.

If the value of Ze = 0.7Ω and disconnection is to occur within 0.4 seconds check for indirect shock protection.
( Definitions Regs : ↔ Indirect Contact . Deleted by BS-7671 :2008 / see Fault Protection ) ←←← *

Length of final circuit 30 metres ( 2.5/1.0mm2 70°C sheath )
TABLE 9A ( On – Site Guide BS-7671;2008 )
Values of resistance for copper and aluminium conductors and of ( R1 + R2 ) at 20ºC in mΩ /metre
Cross-sectional area (mm2) Line Conductor 2.5mm2 / Protective Conductor 1mm2

Resistance/metreor (R1+R2)/metre mΩ /m) Copper : 25.51

30 metres 25.51mW per metre
Total ( R1 + R2 ) = 25.51 mΩ x 30 metres = 765.3 mΩ ( 25.51 x 30 = 765.3 )
Electrical Résistance increases with temperature rise :-
i) Ambient Temperature
ii) Heat Generated by
iii) Heat produced by Other Circuit Conductors

Increase of Résistance with temperature
Remember ! Résistance Increases with Temperature Rise ←←

→ R1 + R2 @ 70°C
→ R1 + R2 @ 20°C
Multiplied by 1.2 gives

Table 9C ( On – Site Guide BS-7671;2008 )
Conductor temperature factors
Conductor installation 70° PVC. Incorporated in a cable or bunched – ( Note : 2 ) → Twin & C.P.C. → Trunking ? → Conduit ?

Value of R1 + R2 calculated at 20°C
To allow for temperature rise multiply by ( 1.2 )
Therefore 765.3 mΩ x 1.2 = 918.36 mΩ
Convert to ohms (Ω) = 918.36 m Ω /1000 ( 0.918Ω

Calculating ( Zs )
Corrected value of R1+R2 = 0.918Ω
Zs = Ze + ( R1 + R2 ) = 0.7 + 0.918 = 1.618Ω

Comparing Results !!
The calculated value of total impedance ( Zs ) must “ NOT “ be greater than tabulated values in ( BS-7671 )
Maximum permitted values of ( Zs )
p/48 : 41.2 - Maximum Values of ( Zs ) for fuseswhere Disconnection is to be within ( 0.4 ) seconds :
p/49 : 41.3 - Maximum Earth Fault Loop Impedance ( Zs ) for Circuit Breakers . Uo / 230V
p/49 : 41.4 - Maximum Earth Fault Loop Impedance ( Zs ) for fuses ( 5s ) Disconnection time with Uo / 230V ( Regulation 411.4.8 )

Note : Regs !! p/48 ( 411.4.5 ) ↔ Alternatively . for nominal voltage ( Uo ) of 230V and a Disconnection time of 0.4s in Accordance with Regulation 411.3.2.2 or ( 5sec ) Accordance with Regulation 411.3.2.3 . the Values Specified in Table 41.3 for the Type and Ratings of Overcurrent Devices . Listed May be Used instead of Calculation . ←←←←←←←←←←←

Where to find maximum values of ( Zs )
Tables 41.2 - page 48
Tables 41.3 - page 49
Tables 41.4 - page 49

Table 41.2
Extract only - Not full tableValues of ( Zs ) for ( 0.4 ) seconds Disconnection
(a) General purpose (gG) fuses to BS 88-2.2 and BS 88-6
Rating (Amperes) 20
Zs (ohms) 1.77

Comparing Results :
Corrected value of ( Line Conductor ↔R1+Earth Conductor ↔ R2 ) = 0.918Ω
Zs = Ze + ( R1 + R2 ) = 0.7 + 0.918 = 1.618Ω

To allow Disconnection to be achieved within ( 0.4 ) seconds the Calculated Value must be within the Tabulated Value
Tabulated value 1.77Ω : > Greater Than ( 1.618Ω ) Therefore circuit complies

Disconnection Times
Equipment Within the Main Equipotential zone ( 0.5 sec ) 17th : Main Protective Bonding Conductor
Equipment Outside the main equipotential zone ( 0.4 sec )

Socket Outlet circuits feeding Portable Equipment intended to be used Outside of the Main Protective Bonding Conductor Zone :
Socket outlet circuits feeding portable equipment used outside 17th Edition
Regulation 411.3.3 requires that an RCD of not exceeding 30mA be provided for: Socket outlets up to 20A that for general use by “ordinary persons”.

 

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Inspection & TestOverview
Why does an Electrical Installation Require Inspection and Testing ?

BS 7671:2008
610.1 ) Every Installation shall, during erection and on completion before being Put into Service be Inspected and Tested toverify,
so far as is reasonably practicable,that the requirements of the Regulations have been Met ←←←←

Before being put into service
“It’s ok misses we've finished the electric's, we've put the supply on”. “be back nextweek to test it”
Simple : If it has not been inspected and tested, it should not be energised . No Discussion – No Connection ←←←←

611.2 Inspection ( Initial Verification ) ↔ ( Testing are Normally Carried Out prior to the Installation being Energised )
The inspection shall be made to verify that the installed electrical equipment is :-
i) in compliance with Section ( 511 ) compliance with standards : ↔ British Standards or Harmonized Standard :
ii) correctly selected and erected in accordance with the Regulations
iii) not visibly damaged or defective so as to Impair Safety

Certification :
Every Inspection and Test must be Recorded on the Appropriate Certificate :

The Installation Certificate
“ what does it consist of ? ”
* Details of Client
* Installation Address - Must include Post Code
* Description and Extent of the Installation
- Signatories those with a responsibility for :-
i) 632.3 . The Design : ↔ ( Initial Verification )
ii) 632.3 . The Construction
iii) 632.3 . The Inspection and Testing

** Recommend date for Next Inspection
Who Recommends the Date for the Next Inspection ( Periodic ) ? THE DESIGNER ←←←←

Who Recommends the Date for SubsequentInspections and Tests ( Periodic ) ?THE INSPECTOR ←←←←

SUPPLY CHARACTERISTICS AND EARTHING ARRANGEMENTS
TN-C ( of Specialist Nature ) p/32
TN-S ( p/33
TN-C-S ( Regs . p/33
TT ( Regs . p/34
IT ( of Specialist Nature )Regs . p/34
*** ( TN-C ) Earthing Requires Special Permission Not Widely Use ←←←←

( 612.1 General :
Some Methods of Tests are Described in IEE Guidance Note 3 Inspection & Testing , published by the Institution of Engineering and Technology, Other Methods are Not Precluded Provided they Give Valid Results ,

Number and Type of Live Conductors :
* Whether the Supply is a.c. or d.c. ( A.C. – Alternating Current Both Ways ) D.C. Direct Current / One Way → )
* Number of Phases { Single-Phase / Three-Phase ( 230V / 400V ) ←←←←
* Number of Poles ? ←←←←

Nature of Supply Parameters !!!!
* Nominal Voltage U/Uo (V)
* Prospective Fault Current, Ipf (kA)
* External Loop Impedance ( Ze ) Ω . Ohms

Prospective Fault Current ( Ipf ) kA ( Regs p/35 Symbols Used in the Regulations ) ↔ ( Ipf )
May be obtained by :-
* Measurement
* Calculation
* Enquiry Public Electricity Supply ( PES )

External loop impedance ( Ze )
May be obtained by :-
* Measurement
* Calculation
* Enquiry

Supply Protective Device Characteristics (PES)
* Type i.e. BS 1361 Type 2, BS 88
* Nominal current rating (A)

 

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Particulars of Installation referred to in the Certificate
* Means of Earthing
* Maximum demand ( Not Rating of Service Head Fuse ) ←←←←
* Details of Earth Electrode Résistance if applicable

Review - Characteristics of Supply
331.1 ↔ The following characteristics of the supply or supplies, from whatever source shall be determined by Calculation, Measurement, Enquiry or Inspection
i) Transient Overvoltages
ii) Undervoltage
iii) Unbalanced Loads
iv) Rapidly Fluctuating Loads
v) Starting Currents
vi) Harmonic Currents
vii) Leakage Current
viii) Excessive Protective Conductor Current ↔ ( Selection of Protective Device to Achieve Discrimination )
xii) Power Factor

Main Protective Conductors
* Earthing Conductor
* Material Cu - Copper etc
* C.S.A.
* Connection verified ( Low Résistance Ohmmeter )

Main Protective Bonding Conductors
* Material Cu - Copper etc
* C.S.A.
* Connection Verified ( Low Résistance Ohmmeter recommended Maximum Value 0.05Ω )

BS /BS- EN Number ( CCU ) fuse/box
Number of Poles
Current Rating
Voltage Rating

Main Switch or Circuit Breaker
* BS Type and Number of Poles
* Current rating (A)
* Voltage rating
* Fuse rating or setting
* Location
* RCD . I∆n ( mA ) and Operating Time ( mS ) at ( I∆n )

Comments on Existing Installation
To be used for Alterations or Additions
Schedule of items Inspected
Refer to ScheduleCommon to both Installation & Periodic Inspection Report

The Visual Inspection
Chapter 61 Initial Verification :
>> Footnote to Regulation ( 610.1 )Precautions shall be taken to avoid danger to persons and to avoid damageto property and installed equipment during inspection and testing

( Remember !! 632.4 : Defects or Omissions revealed during Inspection and Testing of the Installation Work covered by the Certificate shall be Made Good before the Certificate is Issued )

The Visual Inspection
611. Inspection
Inspection shall precede testing and shall normally done with that part of the installation under inspection disconnected from the supply
( That’s Appropriate Form of Disconnection is Isolation ) ←←←←← ****

Test equipment to GS- 38
Safe Isolation PIR
* Fused Leads
* Finger Guards
* 4mm / 2mm Tips

Schedule of Test Results
Refer to Schedule :-
Common to both Installation & Periodic Inspection Report

Periodic Inspection Report ( PIR ) ↔ that’s what they call it .
* Change of Use or Ownership
* As a result of Damage. Fire - Flood etc
* Electrical Overloading
* To Ensure Compliance/continued compliance with the Regulations
* Mortgage/Insurance Request
* Local bylaws - Places of Public Entertainment - Theatres/Cinemas etc ( That’s why you Need your 2391 )

Periodic Inspection Report ( PIR )
* Some areas common to Installation Certificate, i.e.
* Details of client and installation
* Recommended next inspection date
* Signature of competent person
* Supply characteristics
* Particulars of installation

( PIR ) continued
* Schedule of Inspection
* Schedule of Test Results

Major Differences
Estimated age of installation ?
Evidence of Alterations or Additions ?
Are there Records Available ?
Extent and Limitations ( A Big One on -&-s )
Observations and Recommendations

Extent and Limitations
* Extent - Details Indicating what Part/sof the Installation will be Inspected andTested
* Limitations - State exactly what itemsare excluded, i.e. portable appliances,fire alarm systems, emergency lighting,cctv, door entry systems, smokedetectors etc.

Numerical Code :
* Departures from BS-7671:2008 Must be Allocateda Numerical Code
1 ) Requires Urgent Attention
2 ) Requires Improvement
3 ) Requires further Investigation
4 ) Does Not Comply with BS- 7671:2008 ( Imply that Installation is Unsafe )

Minor Works ( 631.3 )
An Alteration or Addition to an Existing Installation that does Not include the Addition of a New Circuit, i.e. Spur to Radial or Ring Circuit etc.

 

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This is Something I knocked Up

Instruments and Testing
Installation Testing

REMEMBER
Visual inspection must precede all testing
→→ Remember →→→ Dead testing precedes

LIVE Testing :

Dead Testing
Isolate before carrying out dead tests ( A Must ) ←←←
* Approved voltage indicator to GS-38
* Maximum of 4mm on exposed prods
* Preferably not more than 2mm
* Fused leads
* Finger guards

Continuity Testing ( Low-Resistance ohmmeter ) ps. You may be asked this on P.Testing )
Battery operated instrument Low voltage d.c.
200mA / 4 – 24V ( 612.2.1 )
Verifying Continuity ( Method 1 ) Caution Supply must be isolated :
( Temporary Link / Instrument Measures ( R1 + R2 )
Along with verification of the cpc, state the Two other tests which are automatically undertaken when carrying out this test
( The value of (R1 + R2) ↔ ( Polarity ) -&-s
***** { Unacceptable practice of connecting c.p.c. to outgoing side of fuse or circuit breaker } *****
Why is it unacceptable ? :-
Unacceptable practiceof connecting c.p.c. tooutgoing fuse orcircuit breaker way

Verifying ContinuityMethod 2
Caution Supply must be isolated :
( Meter Lead on MET ↔ Meter Lead on Pendent or at the Switch )

State Two disadvantages of using Method 2, as compared to Method 1

Use of long wander leadValue of ( R2 ) only obtained
* What consideration should be given to the long wander lead ?
* Its Résistance must be measured anddeducted from the measured value of ( R2 )

Continuity of bondingconductors

Why is it necessary to remove one endof a bonding conductor when verifyingits continuity ?

To avoid the possibility of parallelearth paths ) ←←←←← -&-s
( Break in c.p.c.Parallel path )

Continuity of ferrous enclosures
* visual inspection
* low resistance ohmmeter

Insulation Testing
Instrument must be capable of producing a short-circuit current of 1mA
( you are looking for ! -&-s No Breakdown of the Conductor Insulation )

Caution Supply must be isolated :

Prior to insulation resistance testing :- close main switch if testing from tails
fuses in circuit breakers closed
local switches closed/operate two-way
switches during test
neon's/capacitors disconnected
remove voltage sensitive equipment

Insulation resistance testing between live conductors ( Live & Neutral ) ↔ Neutral is a Live Conductor ←←←← -&-s
Insulation resistance testing between live conductors and earth ( 2 – Leads , one on Earth / one on Brown/Blue Together )

BS 7671 Table 61 - Page 158

State the test voltage and minimum value of insulation permitted for the following circuits :-
* 230V domestic lighting circuit ? 500V – ≥ 1.0MΩ
* 3 phase, 400V motor circuit ? 500V - ≥ 1.0MΩ
* 12V SELV circuit ? 250V ≥ 0.5MΩ
* 750V discharge lighting circuit ? ≥ 1000V - 1.0MΩ
* 50V FELV circuit ? 250V ≥ 0.5MΩ

Live Testing :
Measurement of external impedance ( Ze )
* Main switch open
* Earthing conductordisconnected
* impedance tester ( .35Ω ) ↔ This is Mock Reading

WHY MUST the supply be isolatedbefore disconnecting the earthing conductor ?
Because if you don’t you could possibly kill somebody. If there is a defect with the insulation, and line touches exposed metalwork, the whole of the installation earthing could become live

*** State THREE other instances whereearth-fault loop impedance testing wouldbe required.
* At the furthest point in every final circuit
* At every distribution board
* At every socket outlet

What precautions should be observedwhen undertaking impedance tests withina circuit ?
( Ensure that persons or livestock are not in contact with exposed metalwork )

Measurement of prospective earth fault current
* Prospective faultcurrent tester
* Bonding conductorsconnected

Measurement of prospective short circuit fault current
* Prospective fault current tester

Why is it necessary to verify the valueof prospective fault current at the originof an electrical installation ?
To ensure the rated breaking capacity of the main switch and overcurrent devicesare capable of breaking the prospective fault current level

* State the effect on insulation resistance of an installation if :-

a. additional circuits are added
b. circuits were disconnected/removed
c. the length of a 6A lighting circuit was extended

a. insulation resistance decreases
b. insulation resistance increases
c. insulation resistance decreases

* State FOUR external influences that you would need to consider during the inspection process :-
• corrosion (corrosive atmospheres)
• mechanical damage
• vandalism
• extremes of temperature
• ingress of moisture or water
• extremes of temperature
• explosive atmospheres

 

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Questions & Answers for Examination : 2392-10 : Requirements for Electrical Installations -&-s

Electrical Installations shall be Divided into Circuits to ?
a) help the contractor complete accurate test sheets .
b) allow for more spur circuits
c) reduce unwanted tripping of residual current devices -&-s ***
d) allow for expansion without changing the maximum demand

-&-s ( Regulations 314.1 )
Division of Installation :
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor current produced by equipment in normal operation .
Majority of these Q/A are take from Wiring Regulations 17th Edition .

All circuit within Booths and Fairground premises should be protected at the Origin of Installation by at least a ?
a) 10mA
b) 500mA
c) 100mA
d) 300mA ↔ Correct Answer

-&-s ( Regulations 740.410.3 )

-&-s Love this One ?
740.55.9 : Electric Dodgems / not exceeding 50V a.c 120V d.c. by means of a Transformer in accordance with ( BS-EN61558-2-4 )
Then you ask your self ! 740.551 : 8 > Low Voltage Generating Sets > by means of a Transformer ( Providing these Requirements are Met !!! )
Then you ask your self ! 740 .410.3 > Placing Out of Arms Reach is Acceptable for Electric Dodgems ( see Regulations 740.55.9 )
There you have it 3/Q for 1/Answer , PS -&-s they can go around the long way for a short Cut )

!! The Electricity at Work Regulations 1989 !!
Design, Erection = Verification Electrical Installation in Fairgrounds’ > YES
( Remember / RCDs – Protection for Safety !!!! ) anything that moves RCD it <<<

Incident at Work ? H&S – CSCS

If you are an employer, self-employed or in control of premises, you have a duty ◄ ► to report some accidents and incidents at work
under RIDDOR ◄ ( the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 ). ◄

You Must Report :-
*deaths;
* major injuries; ◄
* over-3-day injuries – where an employee or self-employed person is away from work or unable to perform their normal work duties for more than 3 consecutive days; ◄
* injuries to members of the public or people not at work, where they are taken from the scene of an accident to hospital;
* some work-related diseases; ◄
* some dangerous occurrences – a near miss, where something happens that does not result in an injury, but could have done; ◄
* fatal accidents at work;
* accidents where several workers have been seriously injured; ◄
* accidents resulting in serious injury to amember of the public;

 

[Joe_H]

thanks

 

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Electrical installation is defined in BS 7671 as ‘an assembly of associated electrical equipment supplied from a common origin to fulfil a specific purpose and having certain co-ordinated characteristics.’ For the purposes of Building Regulations and electrical installation means fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter.

Extra-low voltage (ELV) is defined in BS 7671 as ‘normally not exceeding 50 V ac or 120 V ripple-free dc, whether between conductors or to earth.’

Low voltage (LV) is defined in BS 7671 as ‘normally exceeding extra-low voltage but not exceeding 1000 V ac or 1500 V dc between conductors, or 600 V ac or 900 V dc between conductors and earth.’

( Dont mix them Up )

PAT: Portable Appliance Testing: In-Service Inspection and Testing of Electrical Equipment . Synopsis :-

The Electricity at Work Regulations 1989 require any electrical system to be constructed, maintained and used in such a manner as to prevent danger. This means that inspection and testing of systems, including portable appliances, is needed in order to determine if maintenance is required.

( Remember ) ↔ Sitting the 2377-200 exam
The Order of the Questions usually follows the order of the Code of Practice, so a ► Good Tip is that Usually ► Questions that you Encounter
Early on in the Exam will be ►Relating to Information . ► you will be Asked on the -&-s Test ◄

 

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Section 712 : ( Some Small Time Reading )

Photovoltaic’s ( PV ) is the Direct Conversion of Light into Electricity. Certain materials, like Silicon, naturally release Electrons when they are Exposed to Light, and these Electrons can then be harnessed to produce an Electric Current. Several thin wafers of silicon are wired together and enclosed in a rugged protective casing or panel. PV panels produce Direct Current ( DC ) Electricity, which must be Converted to Alternating Current ( AC ) Electricity to run Standard Household Appliances. An Inverter connected to the PV panels is used to Convert the DC Electricity into AC Electricity. The amount of Electricity Produced is measured in Watts ( W ). A kilowatt ( kW ) is equal to 1.000 watts. A Megawatt ( MW ) is equal to 1.000.000 Watts or 1.000 Kilowatts. The Amount of Electricity Used over a given Period of Time is Measured in kilowatt - Hours ( KWh )

712.511 / 1 : Compliance with Standards : BS-EN61215 and :- Must be ► Class 11 ◄ Construction ( on the DC side of PV power supply system ; the Type of Insulation that is Preferable Class 11 ) ( * -&-s )

712.513 / 1 Accessibility : The Selection and Erection of Equipment shall facilitate Safe Maintenance and shall Not Adversely affect Provisions made by the Manufacturer of the PV Equipment to Enable Maintenance or Service Work to be carried Out Safely ( * -&-s )

712.53 : 712.537 : 712.537.2 ) Isolation DC / AC . Locking Off AC – 1 Isolation & Switching ◄► Locking Off DC ** – 2 Isolation & Switching ► ( Padlock ) ( * -&-s )

712.537.2.2.5 : A Switch-Disconnector ◄► shall be Provided on the DC Side of the PV Convertor ►( Warning Labels Must be Placed -&-s ) ◄ ( -&-s would like to Hear : DC Side is Still Live . when power is Cut from the AC Side ) ◄ Isolation 712.537.2 ,

712.410.3.6 : Equipment on the DC. Side shall be Considered to be Energized , even when the System is Disconnected from the AC Side ( * -&-s )

712.54 : Earthing Arrangements and Protective Conductors !! Where Protective Conductors are Installed . they shall be Parallel to and in as Close Contact as Possible with DC Cables and AC Cables and Accessories . ► -&-s would like to Hear : ( Wiring Loops in PV Systems should be kept SHORT as Possible : Reduce ( Excessive Earth Fault )

17th : -&-s . 712.537.2.2.5.1 , All Junction Boxes ( PV Generator and PV array Boxes ) SHALL carry a Warning Label Indicating that PARTS inside the Boxes May Still be Live After Isolation from the PV Convertor

AC Day Light On / Off : DC Night Light Off / On

712.412 : Protective Measure ► Double or Reinforced Insulation . Protection by the Use of Class 11 or Equivalent Insulation shall Preferably be Adopted on the DC Side .

A Must to Remember ( -&-s big time ► 712.411.3.2.1.2 Where an Electrical Installation includes a PV Power Supply System without at ►Least Simple Separation ◄ between the AC Side and the DC Side , an RCD 30mA installed to Provide Fault Protection by Automatic Disconnection of Supply shall be Type B / RCD according to ( IEC 60755 Amendment 2 ( Remember to follow the Manufacturers Intrusion’s -&-s )

Where Would I Use a Junction Box PV ? Consumer Unit ↔ Metter ↔ Inverter ↔ ( AC side / DC side ) Junction Box ↔ PV Modules Wired up to 2 / or more Modules !!!

The Risks : The particular risks associated with solar photovoltaic systems are :-

► PV systems cannot be switched off. Modules produce electricity when exposed to daylight. Hence, unlike most other electrical installation work, the installation of a PV system typically involves working on a live system. Regulation 14 of the Electricity at Work Regulations gives requirements that must be
made to ensure live terminals are either not accessible or cannot be readily touched during installation and maintenance. Such terminals will be live at all times during daylight hours. It is important that anyone opening an enclosure is aware of this.

► An electrician who has come to work on the electrical installation needs to be aware that there is a second source of energy which will also need to be isolated.

PV : RCD 30mA ( can Go Upto 300mA installed to Provide Fault Protection by Automatic Disconnection of Supply. for Bigger Ones .

 

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Electrical Safety Tests Using a Tester : ( Pat. Testing some Small Reading ) this will give you an Insight !!

Power ON / OFF press Until a Bleep is Heard the left hand and Right hand Buttons Marked Class 1 and Class 2 :
Warning : !!! Do Not Touch the Equipment being Tested while the Test is being Carried Out !!! -&-s

Q / Does the Equipment have a 3-Core Mains Lead ( Class1 ) or :- Q / 2-Core Mains Lead ( Class 11 ) ► Class1 ( Earthed ) Equipment , with 3-Core Mains Lead , ► 3 core cord set should be tested as a class 1 appliance : ◄ !!! ► 2 core cord set should be tested as a class 2 appliance : ◄
* Testing a Class 1 Appliance : ► if the Appliance Passes a Visual Inspection Proceed with the Electrical Tests : ◄ ► Connect the Earth Probe to an Exposed Metal Part on the Appliance : ► if the Appliance Under Test has an ON / OFF Switch , Make Sure it is in the On Position : ◄ Q / is the Fuse Correctly Rated for the Equipment ? ◄ -&-s
Q / If the Measured Value is Outside Acceptable Limits a Cross is Placed Next to the Earth Cont !
► a Fail is Indicated and the Test Sequence is Halted : ( This Equipment has Failed the Earth Test ) Red Label

Q / If the Measured Value is within Acceptable Limits a Tick is Placed Next the Earth Cont !
► The Equipment has Passed Earth Test ) Green Label :◄

* The Unit will Proceed with the Insulation Test :
Note : Q / The Power Switch on the Appliance Under Test Must be in the On Position to Perform an Insulation Test , ◄◄
► If the Insulation Résistance is Greater than the Acceptable Limit a Tick is Placed Next to the Insulation Enunciator and Pass
The Equipment has Passed the Insulation Test ,

* Testing a Mains Lead
Plug the Mains Lead Under Test into the IEC Socket and the Front Panel Mains Socket on the , Tester :
► You will now Test the Continuity of the Protective Earth
► If the Measured Value is Outside Acceptable Limits a Cross is Placed Next to the Earth Cont ! Enunciator ,
a Fail is Indicated and the Test Sequence is Halted ,

► if the Measured Value is within Acceptable Limits a Tick is Placed Next to Earth Cont ! Enunciator

* The Unit will Proceed with the Insulation Test ,
► if the Insulation Résistance is Lower than the Acceptable Limit a Cross is Placed next to the Insulation Enunciator and the Test Sequence is Halted : A ) ►The Cord has Failed the Test :

► if the Insulation Résistance is Greater than the Acceptable Limit a Tick is Placed Next to the Insulation enunciator
► The Cord has Passed the Test :

► The Unit will Proceed with the Wiring Test , Checking the Live & Neutral Conductors’ for ( Short or Open-Circuits or Reversed Connections )
► If the Wiring is Correct a Tick is Placed Next to the Cord enunciator and a Pass is Indicated for the Sequence

Testing a Class 11 Appliance : ► Check that the Outer Casing of the Appliance is Complete and Undamaged ◄◄ ( Inspect the Flex and Plug ) ◄◄ Note !! all Class 11 Appliances Must have a Double Square Insulation Sticker On : -&-s
* If the Appliance Passes a Visual Inspection Proceed with Electrical Tests : ► Connect the Earth Probe to the Appliance , there should be No Exposed Metal Parts , ► if the Appliance Under Test has an ON / OFF Switch , make Sure it is in the On Position ► Press the Class 2 Test Key . ► You will now Test Insulation Résistance Note !! The Power Switch On the Appliance Under Test must be in the On Position to Perform an Insulation Test . if No Appliance is Detected { will Display Following .. Operating Instructions }

 

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Q ) If Any Inspection or Test is Not Satisfactory , or you are Doubtful of the Results . ► Take the Equipment Out of Use Immediately ◄► ( Label the Equipment to Show the Reason for Failure )
► -&-s : - “ ID – No “ Means of Identifying the Appliance , Q ) Why Use “ ID Number ! A ) ►Using the ID Number you Avoid Confusing One Item with Another
► H&S – Yellow/Black , Safety Sign !! Caution , Risk of Electrical Shock , Indicates Instructions Must be Followed to Avoid Danger to Person : ► H&S - Yellow /Black , Safety Sign !! Caution , Risk of Danger , the Operating Instructions must be Adhered to in Order to Avoid Danger :
► If the Mains Socket-Wiring is Correct the Display will Show ( L/N at Tick ) ( L/E at Tick ) ( N/E at Tick ) Pass ► if The ( Live & Neutral in the Socket Wiring are Reversed or there is a Fault with the Protective Earth Connection this is Indicated by the Display ( L/N at Tick ) ( L/E . X ) ( N/E . X ) Fail ←←← FaultsIf there is a Fault with the Neutral Connection this is Indicated by the Display , ( L/N . X ) ( L/E at Tick ) ( N/E . X ) Fail ←←← Faults
* Testing an Extension Lead : ►Visually Inspect the Mains Cord and Plug for Signs of Damage : ►Check that the Correct Fuse is Fitted : ►if the Cord Passes a Visual Inspection Proceed with the Electrical Tests :
► 2.5mm2 extension leads are too large for standard 13A plugs, although they may be used with BS EN 60309 industrial plugs. Extension leads exceeding the above lengths should be fitted with a 30mA RCD manufactured to BS 7071.

 

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Remember : ( H&S – CSCS ) British Standard / European Standard / Signs ←← -&-s this will come Up

Q: What Safe Procedure Signs Should I Use ?
A: Safe procedure signs should be situated as to indicate exit routes. At least one sign should be visible from any place within the building.

Q: What are the differences between British Standard ◄ and European Standard ◄ style safe-procedure signs ?
A: British-Standard style signs have symbols and text ; European-standard styles have just ►symbols.◄ It is advised not to Mix the Two Styles .
To avoid confusion, it is advisable to have "final exit" signs at external exit points. These should have a running man symbol and text, but no arrow.