On-Site Guide (BS 7671:2018+A2:2022) (Electrical Regulations)

Product Information

Where tails are buried in walls or enclosed within the fabric of the building, further protection is required (see 7.3.2). It is important that both supplier's and consumer's tails are sufficiently protected from mechanical damage and disturbance by the use of trunking and/or cable clips; see 2.2.6 of this Guide. Notes: (a) Where the LV cables share the same tray then the normal separation should be mel (b) Where LV and telecommunications cables are obliged to cross, additional insulation should be provided at the crossing point; this is not necessary if either cable is armoured.

The division of an installation into two parts with separate 30 mA RCCBs will ensure that part of the installation will remain on supply in the event of a fault. Generally, this is not suitable for an installation forming part of a TT system as there is insufficient fault protection of the single insulated conductors which connect the load side of the doublepole main switch to the supply side of the RCCBs. 'Y Figure 3.6.3(iii) Three-way split consumer unit with separate main switch, two As we have established above, how you identify electrical cable size is through the size of wire it houses e.g. 1.5mm cable houses 1.5mm wire. BS 7671:2018 does not specify requirements for protection against transient overvoltages due to direct or nearby lightning strokes on the structure. For risk management for protection against transient overvoltages due to direct or nearby lightning strokes on the structure, see BS EN 62305-2. Band I (extra-low voltage) circuits must not be contained within the same wiring system (for example, trunking) as Band II (low voltage) circuits unless: This arrangement is a form of electrical separation, where basic protection is provided by basic insulation of live parts or by barriers and enclosures, and fault protection is provided by simple separation of the separated circuit from other circuits and from Earth. The requirements for electrical separation can be found in Section 413 of BS 7671 where one item of equipment is supplied and Regulation 418.3 where more than one item of equipment is supplied by the separated circuit. However, the requirements of Regulation 418.3 could prove difficult or impracticable to meet in a typical application of a portable generator. It is extremely important to note that a portable generator isolated from earth should only be used to supply equipment in the following permutations: ..,. one or more items of Class II equipment ..,. one item of Class I equipment ..,. one or more items of Class II and one item of Class I equipment. The supply of only Class II equipment, however, is preferable. No more than one item of Class I equipment should be supplied at any time as faults can be presented as voltages and operatives can provide a path for current flowing between exposed-conductive-parts of faulty electrical equipment.

Plate switches

For information relating to the permanent use of generators see lET Guidance Notes 5 and 7 and Section 551 of BS 7671 :2018. Where generators are used to supply concession vehicles, such as burger vans, see Section 717 Mobile and Transportable Units of BS 7671 :2018 and lET Guidance Note 7. It would be impossible to cover all of the detail pertained in the book within a summary article. However, please see below a list of key sections and Appendices sub-headings, which should help you to understand what items are broadly available. Sections: Light.ing circuits A maximum voltage drop of 3 per cent of the 230 V nominal supply voltage has been allowed in the circuits; see Appendix F. The circuit is assumed to have a load equal to the rated current (In) of the circuit protective device, evenly distributed along the circuit. Where this is not the case, circuit 76

an intended departure must be recorded on the Electrical Installation Certificate an intended departure not recorded on the Electrical Installation Certificate is unacceptable, as it is simply a non-compliance and the certificate would, therefore, be worthless. Revised, compiled and edited M. Coles BEng(Hons) MIET, The Institution of Engineering and Technology, 2018 a person who possesses, as appropriate to the nature of the electrical work to be undertaken, adequate education, training and practical skills, and who is able to perceive risks and avoid hazards which electricity can create.’ They have suggested, through surveys, that almost half of all severe electrical injury caused in the home is due to DIY work. The most common causes being drilling through wires in the wall, cutting through cables and not turning electrical circuits off before working on them!It follows that single-core non-sheathed insulated conductors must be protected by conduit or trunking and be terminated within a suitable enclosure.