Re-take - Useful Information for 2394 :

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411.4 TN system

411.4.5 The characteristics of the protective devices (see Regulation 411.4.4) and the circuit impedances shall fulfil the following requirement:

Zs × Ia ≤ Uo ≤ Cmin

where: Zs is the impedance in ohms (Ω) of the fault loop comprising:
- the source
- the line conductor up to the point of the fault, and
- the protective conductor between the point of the fault and the source.

Ia is the current in amperes (A) causing the automatic operation of the protective device within the time specified in Table 41.1 of Regulation 411.3.2.2 or, as appropriate, Regulation 411.3.2.3.Where an RCD is used this current is the rated residual operating current providing disconnection in the time specified in Table 41.1 or Regulation 411.3.2.3.

Uo is the nominal a.c. rms or d.c. line voltage to Earth in volts (V).
Cmin ) is the minimum voltage factor to take account of voltage variations depending on time and place, changing of transformer taps and other considerations.
NOTE: For a low voltage supply given in accordance with the Electricity Safety, Quality and Continuity Regulations 2002 as amended,
Cmin ) is given the value 0.95.

NOTE : Where compliance with this regulation is provided by an RCD, the disconnection times in accordance with Table 41.1 relate to prospective residual fault currents significantly higher than the rated residual operating current of the RCD.

 

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414 Protective Measure: Extra-low Voltage Provided by SELV or PELV

414.2. Requirements for basic protection and fault protection

Both basic protection and fault protection are deemed to be provided where:
(i) the nominal voltage cannot exceed the upper limit of voltage Band I, and
(ii) the supply is from one of the sources listed in Regulation 414.3, and
(iii) the conditions of Regulation 414.4 are fulfilled.

NOTE 1: If the system is …......

 

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Protection Against Thermal Effects

421 Protection Against Fire Caused by Electrical Equipment

421.1 General requirements
421.1.1 Persons, livestock and property shall be protected against harmful effects of heat or fire which may be generated or propagated in electrical installations.

Manufacturers’ instructions shall be taken into account in addition to the requirements of BS-7671.

NOTE 1: Harmful effects of heat or fire may be caused by:
- heat accumulation, heat radiation, hot components or equipment
- failure of electrical equipment such as protective devices, switchgear, thermostats, temperature limiters, seals of cable penetrations and wiring systems
- overcurrent
- insulation faults or arcs, sparks and high temperature particles
- harmonic currents
- external influences such as lightning surge.
- inappropriate selection or erection of equipment

NOTE 2: Lightning strikes and overvoltages are covered in BS-EN-62305 and Section 443 of these Regulations.

 

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New regulation .

► 421.1.201
Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS-EN-61439-3 and shall:
(i) Have their enclosure manufactured from non-combustible material, or
(ii) be enclosed in a cabinet or enclosure constructed of non-combustible material and complying with Regulation 132.12.

Note 1: Ferrous metal, e.g. steel, is deemed to be an example of a non-combustible material.
Note 2: The implementation date for this regulation is the 1[SUP]st[/SUP] January 2016, but does not preclude compliance with the regulation prior to that date .

 

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132.12. Accessibility of electrical equipment

Electrical equipment shall be arranged so as to afford as may be necessary:
(i) Sufficient space for the initial installation and later replacement of individual items of electrical equipment
(ii) Accessibility for operation:
- inspection, testing
- fault detection
- maintenance and repair

 

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511 Compliance with Standards

511.1 Every item of equipment shall comply with the relevant requirements of the applicable British or Harmonized Standard, appropriate to the intended use of the equipment. The edition of the standard shall be the current edition, with those amendments pertaining at a date to be agreed by the parties to the contract concerned (see Appendix 1).

Alternatively, if equipment complying with a foreign national standard based on an IEC Standard is to be used, the designer or other person responsible
for specifying the installation shall verify that any differences between that standard and the corresponding British or Harmonized Standard will not result in lesser degree of safety than that afforded by compliance with the British or Harmonized Standard . Such use shall be noted and appended to the appropriate documentation specified in Part 6 .

 

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514.9 Diagrams and documentation

514.9.1 A legible diagram, chart or table or equivalent form of information shall be provided indicating in particular:
(i) the type and composition of each circuit (points of utilisation served, number and size of conductors, type of wiring), and
(ii) the method used for compliance with Regulation 410.3.2, and
(iii) the information necessary for the identification of each device performing the functions of protection, isolation and switching, and its location, and
(iv) any circuit or equipment vulnerable to the electrical tests as required by Part 6 .

For simple installations the foregoing information may be given in a schedule.
A durable copy of the schedule relating to a distribution board shall be provided within or adjacent to each distribution board.

Any symbol used shall comply with IEC 60617.

 

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514.10 Warning notice: voltage

514.10.1 Every item of equipment or enclosure within which a nominal voltage exceeding 230 volts to earth exists and where the presence of such a voltage would not normally be expected, shall be so arranged that before access is gained to a live part, a warning of the maximum voltage to earth present is clearly visible.

 

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521.10 Installation of cables

521.10.1 Non-sheathed cables for fixed wiring shall be enclosed in conduit, ducting or trunking. This requirement does not apply to a protective conductor complying with Section 543.

Non-sheathed cables are permitted if the cable trunking system provides at least the degree of protection IPXXD or IP4X, and if the cover can only be removed by means of a tool or a deliberate action.

NOTE: For a trunking system to meet IP4X requirements, IP4X trunking and related system components would need to be installed. If a system includes site-fabricated joints, the installer must confirm the completed item meets at least the degree of protection IPXXD.

New Regulation .
521.201 Wiring systems in escape routes shall be supported such that they will not be liable to premature collapse in the event of fire.
The requirements of Regulation 422.2.1 shall also apply, irrespective of the classification of the conditions for evacuation in an emergency.

NOTE 1: Non-metallic trunking or other non-metallic means of support can fail when subject to either direct flame or hot products of combustion.
This may lead to wiring systems hanging across access or egress routes such that they hinder evacuation and fire fighting activities.

NOTE 2: This precludes the use of non-metallic cable clips, cable ties or trunking as the sole means of support. For example, where non-metallic trunking is used, a suitable fire-resistant means of support/retention must be provided to prevent cables falling out in the event of fire.

 

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( Out goes equipotential wording ) :svengo:

544 Protective Bonding Conductors :icon_bs:

544.1 Main protective bonding conductors

544.1.2 The main protective bonding connection to any gas, water or other service shall be made as near as practicable to the point of entry of that service into the premises. Where there is an insulating section or insert at that point, or there is a meter, the connection shall be made to the consumer’s hard metal pipework and before any branch pipework. Where practicable the connection shall be made within 600 mm of the meter outlet union or at the point of entry to the building if the meter is external.

 

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559.5 Wiring systems

559.5.1 Connection to the fixed wiring

At each fixed lighting point one of the following shall be used for the termination of the wiring system:
(i) A ceiling rose to BS 67
(ii) A luminaire supporting coupler to BS 6972 or BS 7001
(iii) A batten lampholder or a pendant set to BS EN 60598
(iv) A luminaire to BS EN 60598
(v) A suitable socket-outlet to BS 1363-2, BS 546 or BS EN 60309-2
(vi) A plug-in lighting distribution unit to BS 5733
(vii) A connection unit to BS 1363-4
(viii) Appropriate terminals enclosed in a box complying with the relevant part of BS EN 60670 series or BS 4662
(ix) A device for connecting a luminaire (DCL) outlet according to IEC 61995-1.
(x) An installation coupler BS EN 61535.

NOTE: In suspended ceilings one plug-in lighting distribution unit may be used for a number of luminaires.

559.5.1.201
A ceiling rose or lampholder shall not be installed in any circuit operating at a voltage normally exceeding 250 volts.
559.5.1.202
A ceiling rose shall not be used for the attachment of more than one outgoing flexible cable unless it is specially designed for multiple pendants. 559.5.1.203
Luminaire supporting couplers and devices for the connection of luminaires are designed specifically for the electrical connection of luminaires and shall not be used for the connection of any other equipment.
559.5.1.204
Lighting circuits incorporating B15, B22, E14, E27 or E40 lampholders shall be protected by an overcurrent protective device of maximum rating 16A.
559.5.1.205.
Bayonet lampholders B15 and B22 shall comply with BS EN 61184 and shall have the temperature rating T2 described in that standard.
559.5.1.206.
In circuits of a TN or TT system, except for E14 and E27 lampholders complying with BS EN 60238, the outer contact of every Edison screw or single centre bayonet cap type lampholder shall be connected to the neutral conductor. This regulation also applies to track mounted systems.
559.5.1.207.
A lighting installation shall be appropriately controlled.

NOTE: See Table 53.4 for guidance on the selection of suitable protective, isolation and switching devices.

559.5.1.208.
Consideration shall be given to the provision of the neutral conductor, at each switch position, to facilitate the installation of electronic switching devices.

 

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Part 6
Inspection & Testing :icon_bs:

Chapter 61
Initial Verification

610.5
The verification shall be made by a skilled persons, or persons, competent in such work

▼▼ Out 2015
Some methods of test are described in IET Guidance Note 3, Inspection & Testing, published by the Institution of Engineering and Technology. Other methods of testing are not precluded provided they give valid results

612.12 Check of phase sequence
For polyphase circuits, it shall be verified that the phase sequence is maintained.

Chapter 62
Periodic Inspection & Testing
621.5
Periodic inspection and testing shall be undertaken by a skilled person or persons, competent in such work .

Chapter 63
Certification & Reporting
631.4
Electrical Installation Certificates, Electrical Installation Condition Reports and Minor Electrical Installation Works Certificates shall be compiled and signed or otherwise authenticated by skilled person or persons, competent to verify that the requirements of the Standard have been met.

 

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2015. :icon_bs:

P33. Protective equipotential bonding . Equipotential bonding for the purposes of safety .
P33. Protective bonding conductor . Protective conductor provided for protective equipotential bonding .

Fig 2.1. - Illustration of earthing and protective conductor terms ( see chapter 54)
(2) main protective bonding conductor

544. Protective bonding conductors
544.1. main protective bonding conductors
544.2. Supplementary bonding conductors

612.2.1. Continuity of protective conductors.
including main and supplementary equipotential bonding .

 

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2015 . Watch your wording in Exams .

O.S.G. 4.3. :book:
Main protective bonding of metallic services .
O.S.G. 4.4
Earthing conductor and main protective bonding conductor cross-sectional areas

O.S.G. 4.3.
Main protective bonding of metallic services .
( Figures 2.1 (i) to 2.1 (iii))

The purpose of protective equipotential bonding is to reduce the voltages between the various exposed-conductive-parts and extraneous-conductive-parts of an installation, during a fault to earth and in the event of a fault on the DNO .

411.3.1.2. main protective bonding conductor(s)
are required to connect extraneous-conductive-part is a conductive part, such as a metal pipe , liable to introduce earth potential into the installation or building.

it is common. particularly under certain fault conditions on the LV supply network , for a potential to exist between true Earth, i.e. the general mass of Earth and the earth of the electrical system. Therefore, buried metallic parts which enter the building are to be bonded to the main earthing terminal of the electrical installation.

Examples of extraneous-conductive-parts
(a) metallic installation pipes
(b) metallic gas installation pipes
(c) other installation pipework , for example, heating oil
(d) structural steelwork of the building where rising from the ground
(e) lighting protection systems ( where required by BS-EN-62305)

 

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530.3.1
In polyphase circuits the moving contacts of all poles of a multipole device shall be so coupled mechanically that they make and break substantially together, except: