RCD Lights Bathroom

[diywhoopsy]

We bought some downlighters for bathroom hazard zone 1. The instructions say "It must be fitted with a 30mA RCD"

Knowing little or next to nothing about all this I wonder if you could please help with the following queries:

a) The mains board has a circuit breaker... will this do?

b) If I need to get an RCD what sort should I get and where should I put it considering the light is going to be installed with the electrics in the ceiling void.

 

[delmel]

I have never seen instruction stating lighting should have an rcd fitted. What make are they. Providing they are the correct IPX rating and being low voltage I can see no reason to insist they go on an rcd.

sorry just noticed you have not stated they are low voltage, but in a zone 1 area, i would certainly use low voltage

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moderator

please note 10 a

 

[ban-all-sheds]

Well - if they are not ELV, then to be in Zone 1 they must (to comply with the Wiring Regulations) be protected by an RCD.

a) The mains board has a circuit breaker... will this do?

A circuit breaker is not the same as an RCD - if your CU does not have an RCD, or if it does but the lighting circuit(s) are not protected by it, then you should not use these new lights.

b) If I need to get an RCD what sort should I get and where should I put it considering the light is going to be installed with the electrics in the ceiling void.

These are your options:

1) If your CU has an RCD incomer, or is a split load with the lights on the RCD side - you're OK
2) If your CU is a split load with the lights not on the RCD side - you'll need to move the lighting circuit MCB to the RCD side of the board. To be honest, this is generally regarded as bad design, as if the RCD trips because of a fault on one of the other circuits your lights go out...
3) If your CU has no RCD at all then you will either have to replace the lighting MCB with an RCBO (combined MCB and RCD), if you can get one, or you will have to install a separate RCD in a small enclosure fed from the lighting MCB in the CU and with its output supplying the lighting circuit. It can be any make you like, and it should be installed next to the existing CU.
4) Get 12V downlighters..

Knowing little or next to nothing about all this

Are you doing this yourself, or getting an electrician?

Do you know about Part P of the Building Regulations?

 

[diywhoopsy]

thank you both for taking the time to respond and particularly to ban-all-sheds for going into such detail, clarifying certain points and letting me know what our options are.

ban-all-sheds... when i read your post earlier i didn't know what ELV meant let alone Part P of the building regs i've googled around and now know what this is all about. unfortunately re: Part P, it's now a little too late to follow the regs completely as we installed the lights last night. We will have to ask an electrician to come and check the fittings and install an RCD if you guys think we need one.

many thanks once again for going into such details with the options. i think i have a CU without an RCD but i really don't know as the CU is so old. here's a pic:

could you or anyone else passing through please let me know whether i should go for Option 1, 2 or 3.

thanks

 

[breezer]

what do you suppose that is on the right of your picture, clue: rearange these letters. c, r, d (least thats what it looks like) any chance of a better picture (or what does it say on it)

 

[ban-all-sheds]

Or it's an old ELCB....

 

[Lectrician]

Thats a wylex RCD. Typically 100mA I would think. Very rare to see these in a board. They usually have a plastic shroud top and bottom for surface mounting.

 

[diywhoopsy]

here you go guys...

240v 50Hz
63A Load
30mA Trip
CAT WES 63/2

Below the power switch it reads:
Current Operated Earth Leakage Circuit Breaker...

BTW... test button works okay

 

[delmel]

Nothing wrong with that. Its a good old unit 30ma. Recommend you try out the test button to ensure its working ok.
Ahh see you already did.
I would still use low voltage (which type did you use)

 

[securespark]

Just for informaton....... Wylex introduced this type of metalclad elcb-incomer board in 1974, and they were the first to do so, according to my mate at Wylex.

Yes, Leccy, they are quite rare! In 17 years, I've only seen one!!!!!

 

[ban-all-sheds]

I thought, strictly speaking, an ELCB only detected current actually flowing through the earthing system, not the imbalance caused by it leaking away by some other route like wot an RCD does.

1) Am I wrong?
2) Is the term being used incorrectly here?

 

[securespark]

Ban

AFAIK, the ELCB works in the same way as an RCD, but no doubt if I'm wrong, someone will right me!

PS sitting opposite me on the desk is a cut-out fuse. Do you still want one?

 

[plugwash]

afaict what is mainly reffered to as an ELCB is a voltage ELCB this has two earth terminals with a very small amount of resistance between them and trips if it detects a voltage between tham

BUT that is clearly marked as a current operated ELCB which i belive is the same as a rcd.

 

[ban-all-sheds]

PS sitting opposite me on the desk is a cut-out fuse. Do you still want one?

I do - and I hang my head in shame that I've not got you the info on its rating.

Thing is, when I came to fit my new shower I found I did have a suitable MCB for my CU, and I didn't need to fit a separate unit after all, so I had no need to pull the fuse. And I've just not got round to pulling it just to see what it is - I'm really sorry....

 

[diywhoopsy]

ok folks.... thanks for all the feedback on my jurassic CU

believe it or not, i don't understand everything you guys have said so it's a little difficult for me to know if i have a definitve answer to the original question... however.... with the breadth of knowledge from those who have responded i think i can safely conclude that i do have what is as good as a 30mA RCD.

hey securespark... thanks for asking your mate at Wylex!

fwiw:

when there is anything wrong with electrics in the house everything goes including the lights. i don't mind this at all.

delmel: the lights are not low voltage. they are:

2*50w Zone 1 from B&Q

2*50w Zone 3