Wiring Regulations: New or rewired domestic and similar installations

The good folks at the Electrical Safety Council have a lot of good information when it comes to the Wiring Regulations concerning the new or rewired domestic and similar installations. Below we have compiled a few of the most popular ones out of the 57 such questions and their answers.

Does the 17th Edition require all 13 A socket-outlets in domestic premises to be RCD-protected?

For new installations and rewires in domestic premises, all socket-outlets need to have additional protection by RCD, except perhaps for those intended to supply particular items of equipment such as freezers. Any socket-outlet not having RCD protection needs to be specifically labelled or otherwise suitably identified to indicate its intended use, such as ‘freezer only’. However, if the wiring to a dedicated socket-outlet is concealed in a wall or partition at a depth of less than 50 mm, or if the internal construction of the wall or partition includes metallic parts other than metallic fixings, the circuit will still need to be suitably protected (by RCD or other means).

More info: see Regulation number(s) 411.3.3, 522.6.101, 522.6.102, 522.6.103.

The 17th Edition does not now define a zone 3 in a bathroom or shower room. What electrical equipment and accessories can be installed in the area between 0.6 m and 3.0 m from the edge of the bath or shower basin? Moreover, what minimum degree of IP protection are manufacturers likely to recommend?

There is no change from the 16th Edition requirements – that is, the general rules apply. The manufacturer’s installation instructions must always be followed.

More info: see Regulation number(s) 512.2, 134.1.1

Where the Regulations specify additional protection by RCD, does this include RCBOs?

Yes. Where the generic term ‘RCD’ is used, it refers to most types of residual current device including RCBOs (Residual current-operated circuit-breakers with integral overcurrent protection), RCCBs (Residual current-operated circuit-breakers without integral overcurrent protection) and SRCDs (Socket-outlets incorporating a residual current device). For the purposes of the Regulations, it does not include PRCDs (Portable residual current devices).

More info: see Regulation number(s) 411.3.3

Can accessories and electrical equipment such as socket-outlets and under-cupboard lighting be fixed to fitted kitchen units?

Yes, provided that they are securely fixed to rigid parts of the units that are not demountable or otherwise liable to be disturbed in normal service. However, care must be taken to comply with all the relevant requirements of BS 7671, including accessibility for inspection, testing and maintenance, and provision of adequate protection against damage (by impact or water for example) for the accessories, equipment and associated wiring.

More info: see Regulation number(s) 530.4.2

Read the entire FAQ on this subject via ESC, or more articles on this topic at, Electrical Safety and Wiring Regulations.