RCD Protection

[ml1936]

If you add spots to an existing lighting circuit, do you need to provide RCD protection to it? Because as I read regs, you only need to RCD protect the cables you add to the circuit and only if the are buried less than 50mm under plaster. So if spots are in ceiling more than 50mm then why would they need protecting?

 

[Spark123]

The cables need to be 50mm from top and bottom of the joist or another method of protection needs to be implemented.
The fact the back of the spot is deeper than 50mm isn't an issue.
RCD protection is required for unprotected concealed cables in a wall or partition, this reg doesn't cover under a floor or above a ceiling.

 

[ml1936]

Yeah so if daisy chaining from one spots to another in a ceiling with the cables above joists or more than 50mm away, then no RCD would be needed on the circuit?

 

[Spark123]

Yep (unless there is another reason for one!)

 

[ericmark]

The cables need to be 50mm from top and bottom of the joist or another method of protection needs to be implemented.
The fact the back of the spot is deeper than 50mm isn't an issue.
RCD protection is required for unprotected concealed cables in a wall or partition, this reg

522.6.6

doesn't cover under a floor or above a ceiling.

but 522.6.5 does so your statement is misleading.

A cable installed under a floor or above a ceiling shall be run in such a position that it is not liable to be damaged by contact with the floor or the ceiling or their fixings. A cable passing through a joist within a floor or ceiling construction or through a ceiling support (e.g. under floorboards), shall:
(i) be at least 50 mm measured vertically from the top, or bottom as appropriate, of the joist or batten, or
(ii) incorporate an earthed metallic covering which complies with the requirements of these Regulations for a protective conductor of the circuit concerned. the cable complying with BS 5467, BS 6346. BS 6724, BS 7846, BS EN 60702-1 or BS 8436, or
(iii) be enclosed in earthed conduit complying with BS EN 61386 and satisfying the requirements of these Regulations for a protective conductor, or
(iv) be enclosed in earthed trunking or ducting complying with BS EN 50085 and satisfying the requirements of these Regulations for a protective conductor, or
(v) be mechanically protected against damage sufficient to prevent penetration of the cable by nails, screws and the like.

Another exception would be a bathroom where everything needs RCD protection. The use of Ali-Tube to BS 8436 Guardian, Earthshield, Flexishield, or Afumex would also remove the need for RCD protection and where existing wiring is being extended it would seem the simple method of compliance.

 

[Spark123]

Please can you point to the part of regulation 522.6.5 which requires RCD protection?
What is wrong with saying the reg which requires a cable in a wall or partition (522.6.6) requires RCD protection doesn't cover ceilings or floors (522.6.5), they are two separate regulation numbers??

I feel a bathroom or a TT system will fall under the "unless there is another reason for one!" category.