Outside light RCD protection

AJshep · Nov 18, 2018

spinlondon said:
For those of you who want to drag up the definition of a DB/CU, and say that an FCU is a DB/CU.
Just remember 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.”

Spin, You are probably correct and I respect that you have spent a bit of time researching this regulation.
All I did was brought up the definition of "Circuit" never once did I say an RCD FCU was a DB or CU so I dont see why it would it need to bound to same constraints ?

I was just looking at Regulation 411.3.4 and your right !! The difference between this regulation and 411.3.3 which covers socket outlets is the part.. "provided for AC final circuits"

Thats why I posted the definition on circuit, it wasnt to be akward or disagree, I was also always taught when putting a FCU on a final circuit then you are changing the characteristics of the addition so the circuit starts from the point where the overcurrent protective device changes, and ive occasionally put a Sw fcu with a 3amp fuse on a rfc to supply a light in a cupboard, as Ive been using logic.

Midwest · Nov 18, 2018

Interesting discussion, I've not got the BBB nor had any training etc on the 18th.

Previously I sort guidance on reg 701.411.3.3, and was advised that the protection of low voltage circuits serving locations (bathrooms etc), would be compliant utilising a local RCD FCU.

Albeit I take spinlondon's point of definition of circuit. However that definition does say '....protected against overcurrent by the same protective device'.

With regard 411.3.4, if I replaced a ceiling rose with a new luminaire, or re-terminated the fixed wiring with a jb of some sort, and extending the wiring with additional cabling, then the existing circuit would now need additional protection at the origin to comply? Or as in this case, additional fixed wiring, would also been at the origin and not locally as above.

I think I would need to seek some guidance on this point. Otherwise in a domestic environment, I could see sparks losing a lot of work, if this is the case.