Re-take - Useful Information for 2394 :

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Reasonably-practicable or absolute

If the requirement of the regulation is absolute, then that regulation must be met regardless of cost or any other consideration.
If the regulation is to be met ‘ so far as is reasonably practicable ’ , then risks, cost, time, trouble and difficulty can be considered.

You may come across it as

( “ so far as is reasonably practicable ” )
( “ as low as reasonably practicable ” ).
is the term most often used in the Health and Safety at Work etc Act and in Regulations.

 

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The definition of “ Electrical equipment “ is very brood , including anything used or intended to be used or installed for use :

The term “ Equipment “ as the BS-7671:
Definition makes clear , relates to ( All ) equipment that will be utilized in an electrical-installation , So as to be clear as to what is included , in BS-7671: definition of “ Electrical equipment “ is repeated below :

P/27 , Electrical equipment : ( abbr: Equipment )
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 .

Electric installation : ( abbr: Installation )
An assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes .

Fundamental requirements for selecting all “ Equipment “

It is important to note . that the selection & erection requirements of the 17[SUP]th[/SUP] Edition do not generally repeat the requirements contained within the equipment’s product Standards . Instead , BS-7671: addresses equipment solely in accordance with installation-requirements ( Regulation 113.1. )

When selecting equipment , the following must be considered :

• Compliance with the appropriate product Standard’s :
• Suitability for the anticipated operational condition’s :
• Suitability for the anticipated , External influences :
• Provides adequate accessibility for , maintenance :

( Regulation 113.1. ) Equipment :
The Regulation’s apply to items of , electrical-equipment only so far as selection & application of the Equipment in the installation are concerned , The Regulation’s do not deal with requirements for the construction of assemblies of electrical-equipment , which are required to comply with appropriate Standards .

Electrical equipment : ( abbr: Equipment ) BS-7671

 

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Testing :

The difference between a Certificate and a Report

As its title suggests, an Electrical Installation Certificate certifies that new electrical installation work complies with the current edition of BS-7671: it is not suitable for reporting on the condition of an existing installation and should not be used for that purpose.

P/392. ( EIC ) This safety Certificate has been issued to confirm that the electrical installation work to which it related has been designed , constructed ,inspected & tested in accordance with British Standard 7671 ( the IET Wiring Regulations )

( EIC )
Such certification includes a declaration that the installation work has been designed, constructed and inspected and tested in accordance with the requirements of BS-7671 it is a ( declaration that the installation is safe to be taken into service )

Similarly, an Electrical Installation Condition Report is not suitable for the initial certification of a new installation, or of new work associated with an alteration or addition to an existing installation, and so should not be used for that purpose.

On completion of the initial verification of an electrical installation, or of an alteration or addition to an installation, an Electrical Installation Certificate (EIC) or Minor Electrical Installation Works Certificate (MEIWC) should be issued ( Regulation 631.1 of BS-7671 refers ).

The certificate issued should be based upon the model form given in Appendix 6 of BS-7671 and should include a record of the inspection activities performed and the results of the testing carried out as part of the verification process.

Importantly, an EIC or MEIWC must not be issued until any defects or omissions revealed during the verification of the installation work covered by the certificate have been remedied ( Regulation 632.4 of BS 7671 refers ).

Such certification includes a declaration that the installation work has been designed, constructed and inspected and tested in accordance with the requirements of BS-7671. In short, it is a declaration that the installation is safe to be taken into service.

( EICR ) .. The report contains a summary of the overall condition of the installation in terms of whether it remains Satisfactory, or is Unsatisfactory, for continued use.

On completion of the periodic inspection and testing of an electrical installation, an Electrical Installation Condition Report ( EICR ) should be issued ( Regulation 634.1 of BS-7671 refers ). The report should be based upon the model form given in Appendix 6 of BS-7671 and should include a record of the inspection activities performed and the results of the testing carried out as part of the periodic inspection process.

The report details the outcome of an assessment of the in-service condition of an electrical installation against the requirements of the issue of BS-7671 current at the time of the inspection, irrespective of the age of the installation or to which edition of the Wiring Regulations it was designed. Details of any damage, defects, deterioration, non-compliances or dangerous conditions should be recorded on the report (Regulation 634.2 of BS-7671 refers).

Electrical :
( EIC ) .. Installation Certificate . New installation :
( EICR ) .. Installation Certificate Report .. Existing property :

 

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Protective-earthing , requires all exposed-conductive-parts to be connected to a protective conductor which in turn is connected to the main earthing terminal and hence, via the earthing conductor to the means of earthing

Main-protective-equipotential-bonding
In each installation main protective-bonding-conductors complying with Chapter 54 are required to connect to the main earthing terminal extraneous-conductive-parts, such as water & gas installation pipes, other installation pipework and ducting, central heating , air conditioning systems and exposed metallic structural parts of the building.

Automatic disconnection in case of a fault
When a fault occurs, the fault current has to be of sufficient magnitude to operate the circuit protective device to automatically disconnect the supply to the faulty circuit within a prescribed time. ... ( RCD in earth fault condition's 0.04s )

( an RCBO ) may be employed. Where an RCD is used for fault protection .

Basic protection provided by ... Insulation or barriers & enclosures
Fault protection provided by ... Protective earthing , Protective bonding , Automatic disconnection . ( ADS )

RCD : used for , Addition protection & Fault-protection

Additional protection
BS-7671 recognizes this measure as reducing the risk of electric shock in the event of failure of one or other of the two basic protective measures
( Insulation & Barriers or Enclosures ) and/or failure of the provision for fault protection or carelessness by user(s)

 

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Protective measures

A protective measure must consist of provision of basic protection & provision of fault protection, which normally are independent.
For example, in the case of automatic disconnection of supply .

Basic protection is provided by insulation & barriers and enclosures .
Fault protection is provided by protective earthing, protective bonding & automatic disconnection of supply .

Basic & fault protection are independent .

Basic protection is defined as:
P/23 : Protection against electric shock under fault-free conditions

Basic protection is provided to protect persons or livestock coming into direct contact with live parts

Protection under fault conditions or fault protection is defined as:
P/28 : Protection against electric-shock under single fault conditions

Fault protection provides protection against persons or livestock coming into contact with exposed-conductive-parts which have become live under single fault conditions

P/27 : Exposed-conductive-part is defined as:
Conductive part of equipment which can be touched and which is not normally live but which can become live under fault conditions

Basic protection & Fault protection : ... " Protection against electric-shock "
Additional-protection : ... " Protection against electric-shock "

" Protection against electric-shock "
p/51 : Note : In electrical installation's the most commonly used protective measure is ( ADS ) Automatic disconnection of supply

Fault protection is provided by :
p/32 : Protective-earthing , Earthing of a point or points in a system or in an installation or in equipment for the purposes of Safety
P/32 : Main-protective-equipotential-bonding equipotential bonding for the purpose of Safety
P/23 : Bonding-conductor A protective-conductor providing equipotential bonding . ( Equal-bonding )
Automatic disconnection of supply in the case of a fault.

P/51 : Chapter 41 : Protection against Electric Shock .
This chapter deals with protection against electric-shock as applied to electrical installations .

refer . P/51 . 2011:
in BS-7671:2001:
i) protection in use without a fault ( now designated basic protection ) was referred to as protection against direct-contact .
ii) protection under fault-conditions ( now designated fault protection ) was referred to as protection against indirect-contact .

411.3. : Requirements for fault-protection .
411.3.1. : Protective earthing & protection equipotential bonding .
411.3.1.1. : Protective earthing .

411.3.2. Automatic disconnection in case of a fault .

Protective measure : ( ADS ) 411
411.1. General
Automatic disconnection of supply is a protective measure in which :

i) Basic-protection is provided by ( Basic insulation of live-parts or by barriers or enclosures )
ii) Fault-protection is provided by protective-earthing , protective-equipotential-bonding & automatic disconnection .. in case of a fault .

 

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Dimming-equipment : can vary from simple dimmer switches, used in domestic situations, to large, multi-way dimming units

Testing

BS 7671 requires that all circuits are inspected and tested prior to being put into service; see Regulation 610.1.
The testing sequence is given in Section 612 of BS-7671 and will not be reiterated here but there are a number of points worth highlighting.

When undertaking insulation resistance testing, Table 61 shall be applied, e.g. test voltage of 500 v d.c. with a minimum insulation resistance measurement of 1 MΩ, when verifying insulation resistance between non-earthed protective conductors and Earth. Where equipment is likely to influence the verification test, or be damaged, such equipment the test voltage for the particular circuit may be reduced to 250 V d.c. but the insulation resistance shall have a value of at least 1 MΩ.

Regulation 612.3.3 recognises that where the circuit includes electronic devices which are likely to influence the results or be damaged during the test, a measurement between the live conductors connected together and the earthing arrangement only can be made.

In the event of a fault of negligible impedance, protective devices in all lighting circuits should disconnect the fault within the required time or supplementary provisions are applied to achieve the same degree of safety. The use of non-standard equipment is not a barrier to electrical installation design but the designer must ensure that the level of safety is not compromised.

The requirements of BS-7671:2008
Equipment :
Regulation 511.1 of BS-7671:2008 requires that all equipment complies with the relevant requirements of the applicable British Standard, or Harmonised Standard, appropriate to the intended use of the equipment.

Where equipment is not manufactured to a recognised standard, as highlighted , Regulation 511.2 requires that such equipment offers the same degree of safety as that afforded by compliance with the Regulations; this is also recognised in Chapter 12.

Fundamentally, the ( Regulations do not apply to electrical appliances (( but )) , as the dimming equipment is controlling outgoing circuits - that can be considered as part of the electrical installation - it would be necessary to make reference to this instance as a departure from BS-7671 in the Electrical Installation Certificate; Regulation 120.3 requires the designer to follow technical requirements intended to ensure that electrical installations conforms to the fundamental principles of Chapter 13 and states:

Any intended departure from these Parts requires special consideration by the designer of the installation and shall be noted on the Electrical Installation Certificate specified in Part 6. The resulting degree of safety of the installation shall be not less than that obtained by compliance with the Regulations

Therefore, the Regulations are not a barrier to non-standard equipment but designers must ensure the equipment used is just as safe as equipment made to recognised standards.

Regulation 515.1 requires that there be no harmful effect between electrical and other installations. The best approach, where practicable, is to arrange that the installations are kept separated. Elevated temperatures from hot running dimmer units in hot environments need to be considered and such sources of heat kept separate from susceptible parts of the building fabric or theatrical properties.

Regulation 515.2 requires that where equipment carrying current of different types or at different voltages is grouped in a common assembly (such as a switchboard, a cubicle or a control desk or box), all the equipment belonging to any one type of current or any one voltage shall be effectively segregated wherever necessary to avoid mutual detrimental influence.

 

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Regulation 621.5 states that Periodic Inspection & Testing shall be undertaken by a competent person.

Regulations apply to design, erection and verification of electrical installations, also additions and alterations to existing-installations. Existing installations that have been installed in accordance with earlier editions of the Wiring Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.

 

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Useful Junk .

How did it all Start : !!! Number of socket-outlets

( Parker Morris Report ) How many socket do you require in a house !!!!

Firstly :
All equipment must be “ fit for purpose “ as the law demands bearing in mind the purpose to which the equipment is to be put , its use and the environmental condition in which it is to be used .
SAFETY

It has already been stated that the number of socket-outlets being advocated is primarily on the grounds of safety. The resulting dangers of not having sufficient socket-outlets may be summarised as follows:

• If there is no convenient socket at the location where the user wishes to use the appliance, he will almost certainly take steps to overcome the problem himself. This will either mean lengthening the flex or providing a ‘ do-it-yourself ’ extension to the socket. In both cases, there is a likelihood that this will not be done properly, resulting in a dangerous electrical situation often involving a loss of earthing at the point where it is required.

• If the longer flexes are provided there is a serious risk of these being stumbled over. Falls are the most common cause of accidents in the home. Such accidents are not considered ‘ electrical accidents ’. Long flexes placed under carpets, etc are equally liable to create a fire danger with continuous traffic over them and also lead to incorrect and hazardous use of mains connectors.

• With sufficient socket-outlets available adaptors may be used. ( Adaptors not designed for continuous loading of high current can overheat ) Moreover, ( several appliances connected to the same socket mean that these may be left alive even though they are not in use ) , since there is no individual controlling switch. This is an additional danger, as is the possibility of overloading.

• There are two principal dangers arising from a poor electrical installation and associated equipment. They are either the personal risk of electric shock or the damage to individuals and property through fire. So far as the electric shock is concerned, there are no specific statistics available other than those of fatalities directly attributable to an electrical cause.
PART P OF THE BUILDING REGULATIONS

From 1st January 2005 electrical installation work carried out in dwellings in England and Wales will become subject to Part P of the Building Regulations.

Part P imposes the requirement that:

“ Reasonable provision shall be made in the design, installation and testing of electrical installations in order to protect persons from fire or injury ”.

and that:

“ Sufficient information shall be provided so that persons wishing to operate, maintain or alter an electrical installation can do so with reasonable safety ”.

THESE REQUIREMENTS APPLY TO ALL ELECTRICAL INSTALLATION WORK CARRIED OUT IN DWELLINGS IN ENGLAND AND WALES. FAILURE TO MEET THESE REQUIREMENTS WILL BE A CRIMINAL OFFENCE.

In addition, as a consequence of Part P, from 1 January 2005 electrical installation work in dwellings in England and Wales will count as “ building work ” , as defined in the Building Regulations 2000, and hence should be notified to a Building Control Body before the work commences, unless:

(1) the proposed work is to be undertaken by a Competent Person (an individual or a company authorised to selfcertify compliance on completion of the work); or

(2) the proposed work is of a minor nature.
Further information regarding Part P of the Building Regulations can be found at Partp.co.uk

CONVENIENCE

If socket-outlets are not conveniently placed to the user they will not be used. Also, unless they are reasonably placed along the wall and located on several walls in the room, the danger of trailing flexes will not be removed. Thirty five percent of families move house every 5 years or less and a further 23% move house at intervals of less than 10 years *. Each family has a different arrangement of furniture and pattern of living. This point was made in the ( Parker Morris Report ) , but has seldom been taken note of. However it is common experience that in every home there is at least one socket-outlet in the living area, which is unusable due to furniture being placed in front of it, and this frequently happens in bedrooms as well.

” General Household Survey ”. HMSO

 

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( Parker Morris Report ) Recommended Minimum Quantity of Double-Socket-Outlets for Dwellings .

This is the ( ECA's ) take on it, an upgraded version of the , Parker Morris Report

How many socket do you require in a house IET Regulation

BS-7671:2008: 2011: O.S.G. P/178 . There is much in the 1961 report that still rings true today.
H7 Number of Socket-outlets .

553.1.7. Sufficient socket-outlets are required to be installed so that all equipment likely to be used can be supplied from a reasonably accessible socket-outlets , taking account of the length of flexible cable normally fitted to portable-appliances and luminaires . Table H7 provides guidance on the number of socket-outlets that are likely to meet this requirement .

( Parker Morris Report ) Table 1 – Minimum Number of Socket Outlets to be Provided in Homes

All socket-outlets should be of the ( twin-switched-type )

Room Type

Smaller Dwellings Rooms Typically ( 4 / 12m[SUP]2[/SUP] ) ...
- Main Living Room ( see note 4 ) Socket-Outlets 4
- Dining Room , Socket-Outlets 3
- Single Bedroom , Socket-Outlets 2
- Double Bedroom , Socket-Outlets 3
- Studies , Socket-Outlets 4
- Utility Rooms , Socket-Outlets 3
- Kitchens ( see note 1 ) Socket-Outlets 6
- Garage ( see note 5 ) Socket-Outlets 1
- Conservatories , Socket-Outlets 2
- Halls ( see note 4 ) Socket-Outlets 1
- Lofts , Socket-Outlets 1

Note: In accordance with BS 7671 (Regulations for Electrical Installations) all socket outlets likely to supply portable equipment used 30mA residual current device.

2011: O.S.G. Table H7 .. Minimum number of ( Twin-socket-outlets ) to be provided in homes .
Smaller rooms ( up to 12m[SUP]2[/SUP] )

- Main Living Room ( see note 4 ) Socket-Outlets 4
- Dining Room , Socket-Outlets 3
- Single Bedroom ( see note 3 ) Socket-Outlets 2
- Double Bedroom ( see note 3 ) Socket-Outlets 3
- Bedsitting room ( see note 6 ) Socket-Outlets 4
- Study Socket-Outlets 4
- Utility Rooms , Socket-Outlets 3
- Kitchens ( see note 1 ) Socket-Outlets 6
- Garage ( see note 2 ) Socket-Outlets 2
- Conservatory , Socket-Outlets 3
- Hallways , Socket-Outlets 1
- Loft , Socket-Outlets 1
- Location containing a bath or shower , ( note 5 )

 

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( Parker Morris Report ) Table 1 – Minimum Number of Socket Outlets to be Provided in Homes
Medium Dwellings Rooms Typically ( 9 / 25m[SUP]2[/SUP] )

- Main Living Room ( see note 4 ) Socket-Outlets 4
- Dining Room , Socket-Outlets 3
- Single Bedroom , Socket-Outlets 3
- Double Bedroom , Socket-Outlets 3
- Studies , Socket-Outlets 4
- Utility Rooms , Socket-Outlets 4
- Kitchens ( see note 1 ) Socket-Outlets 8
- Garage ( see note 5 ) Socket-Outlets 1
- Conservatories , Socket-Outlets 3
- Halls ( see note 4 ) Socket-Outlets 2
- Lofts , Socket-Outlets 1

Note: In accordance with BS 7671 (Regulations for Electrical Installations) all socket outlets likely to supply portable equipment used 30mA residual current device.

2011: O.S.G. Table H7 .. Minimum number of ( Twin-socket-outlets ) to be provided in homes .
Medium rooms ( up to 12 / 25m[SUP]2[/SUP] )

- Main Living Room ( see note 4 ) Socket-Outlets 6
- Dining Room , Socket-Outlets 4
- Single Bedroom ( see note 3 ) Socket-Outlets 3
- Double Bedroom ( see note 3 ) Socket-Outlets 4
- Bedsitting room ( see note 6 ) Socket-Outlets 5
- Study Socket-Outlets 5
- Utility Rooms , Socket-Outlets 4
- Kitchens ( see note 1 ) Socket-Outlets 8
- Garage ( see note 2 ) Socket-Outlets 3
- Conservatory , Socket-Outlets 4
- Hallways , Socket-Outlets 2
- Loft , Socket-Outlets 2
- Location containing a bath or shower , ( note 5 )

( Parker Morris Report ) Table 1 – Minimum Number of Socket Outlets to be Provided in Homes
Larger Dwellings Rooms Typically ( 25 / 225m[SUP]2[/SUP] )

- Main Living Room ( see note 4 ) Socket-Outlets 6
- Dining Room , Socket-Outlets 4
- Single Bedroom , Socket-Outlets 3
- Double Bedroom , Socket-Outlets 3
- Studies , Socket-Outlets 6
- Utility Rooms , Socket-Outlets 4
- Kitchens ( see note 1 ) Socket-Outlets 10
- Garage ( see note 5 ) Socket-Outlets 2
- Conservatories , Socket-Outlets 4
- Halls ( see note 4 ) Socket-Outlets 2
- Lofts , Socket-Outlets 1

Note: In accordance with BS 7671 (Regulations for Electrical Installations) all socket outlets likely to supply portable equipment used 30mA residual current device.

2011: O.S.G. Table H7 .. Minimum number of ( Twin-socket-outlets ) to be provided in homes .
Larger rooms ( more than up to 25m[SUP]2[/SUP] )

- Main Living Room ( see note 4 ) Socket-Outlets 8
- Dining Room , Socket-Outlets 5
- Single Bedroom ( see note 3 ) Socket-Outlets 4
- Double Bedroom ( see note 3 ) Socket-Outlets 5
- Bedsitting room ( see note 6 ) Socket-Outlets 6
- Study Socket-Outlets 6
- Utility Rooms , Socket-Outlets 5
- Kitchens ( see note 1 ) Socket-Outlets 10
- Garage ( see note 2 ) Socket-Outlets 4
- Conservatory , Socket-Outlets 5

 

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The Scope of BS-5839: Pt 6 .

This code of practice cover fire alarm systems starting from a simple self-contained battery-smoke-alarm right through to major systems with central panel/s in accordance to BS-5839 - pt 1 .

BS-5839: Pt 6 covers the following domestic building types .
Bungalows
Multi-storey houses
Individual flats
Individual maisonettes
Mobile homes
Individual sheltered accommodation as well as their common parts
Houses in multiple occupation ( HMOs )
Certain NHS housing in the community
Mansions
Shared houses
Houses divided into several self-contained single-family dwelling units .

Not included are hostels , caravans , boats ( Other than permanently moored ) & mmunal parts of blocks or flats or maisonettes .

Basic design guidance for most domestic installations (Grade D, Category LD3)
Where more than one alarm is provided they should be interconnected, so that detection by one unit operates the alarm signal in all of them.

Typically, a steady Green-light simply means that it is receiving AC power.

These are powered by two power sources.
Main’s power & battery power. The battery power operates the detector should the fire interrupt the house main’s .

 

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Unfortunately : there is ( No-legal-Requirement ) to carry out Periodic Inspection & Testing of premises within the UK ... ( Why the Hell - NOT )
( Why is so many Electrician’s. Unemployed ) ... Business for Sale .

 

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What types of mechanical protection provide sufficient protection against penetration by nails, screws and the like .

As an example, steel of 3 mm minimum thickness is generally considered to provide sufficient mechanical protection, except where shot-fired nails are likely to be used.

Regulation number(s) 522.6.101 , 522.6.103

 

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[h=4]Does the device that has to be provided for switching off a bathroom extract fan for mechanical maintenance need to be located adjacent to the fan[/h][h=4][/h][h=4]No, but the device does need to be so placed and marked as to be readily identifiable and convenient for the intended use[/h]Regulation number(s) 537.3.2.4 . P/152
[h=4][/h]

 

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[h=4]Does the 17th Edition permit connection of smoke alarms to an adjacent lighting circuit taking into account Regulation 560.7.1, which states that circuits of safety services shall be independent of other circuits[/h][h=4][/h]Yes. The particular requirements of BS 5839-6 take precedence over the general requirements of BS-7671
Regulation number(s) 110.1