Additional lighting point in an existing installation

Post Reply
Jabba
Posts: 15
Joined: Tue May 04, 2021 7:19 pm
Answers: 0
Has thanked: 7 times
Been thanked: 0

Additional lighting point in an existing installation

Post by Jabba »

I have a question about the requirement for an earth at a lighting point in an existing installation wired in 2 core.

5.4.3 requires an earthing conductor at every lighting point.

If I was just replacing a fitting I would not be required to earth the fitting unless the fitting required it. However if I say replaced a batten holder in a room with 2 downlights in that room, even though the earth is not used would I be required to earth the fittings?
My thoughts are yes as an earth is required at the transformer for ELV lighting systems. However does 5.4.1 exception for double insulation come into play or does that not relate to this?

Thanks
JamieP
Posts: 478
Joined: Tue Apr 14, 2020 11:08 am
Answers: 0
Has thanked: 92 times
Been thanked: 18 times

Re: Additional lighting point in an existing installation

Post by JamieP »

5.4.1 is different in saying something isn't required to be earthed if it's double insulated, which still stands true with lighting points, you don't need to earth them if double insulated but because of 5.4.3 you must have an earth present.

So as you said f you replace an existing fitting that have 2 core wiring and no earth then there is no requirement to get an earth there, unless the new fitting is a class 1 fitting. A class 2 or DI fitting doesn't require an earth to be run.

If you make an alternation or extend/install new parts to an existing circuit then all those parts must meet 5.4.3, in your case 2 new downlights with wiring altered or installed to suit

5.4.3 says regardless of fitting type, we must have an earth there, 5.4.3 exception 2 means we don't need an earth at the light fitting but as the original text says, we must have it at the ELV transformer

So regardless of what type the light fitting or transformer for the lighting point are, we must have
"A protective earthing conductor, connected to a terminal or suitably
insulated and enclosed, shall be provided" at the ELV transformer

This also obviously means that all the earths must be connected through not cut off like I've seen in some cases because without being connected you don't have an earth there, you simply have a piece of copper with green/yellow insulation doing nothing

Also means when we do our testing that we must confirm earth continuity is sufficient regardless of if it's being used currently or not

5.5.2 deals with where we can or can't connect such PEC but I'd believe the most common arrangement would be to run a 2.5mm single core earth from the switchboard that supplies the fittings
Jabba
Posts: 15
Joined: Tue May 04, 2021 7:19 pm
Answers: 0
Has thanked: 7 times
Been thanked: 0

Re: Additional lighting point in an existing installation

Post by Jabba »

Thanks for the clarification Jamie. So even though it doesn’t need to be earthed then PEC still needs to be there as required by 5.4.3.
JamieP
Posts: 478
Joined: Tue Apr 14, 2020 11:08 am
Answers: 0
Has thanked: 92 times
Been thanked: 18 times

Re: Additional lighting point in an existing installation

Post by JamieP »

Correct, for the very purpose of if it is swapped that there is an earth there ready regardless and I believe this is more aimed at homeowners who are unlikely to care or know what to do if an earth isn't there and probably install a fitting regardless
Post Reply