RCD required?

[HappyHippyDad]

Afternoon all..

I should know the answer to this but I'm away from home where all my files are and I must admit I'm never too sure about lights and RCD protection!!

I will be changing some ELV downlights to GU10 fittings and wondered if I needed RCD protection? I cant see why as I wont be burying the cables and its not in a special location but just not 100% sure, especially with amd 3 just arriving.

I may well add it anyway as it is a Wylex board and I could add an RCBO but I'm just interested in what the regs say with regards RCD protection and this scenario.

Thanks.

 

[Breeze]

I wouldn't class this as like for like.

I'll be changing a non-earthed ELV fitting to an earthed mains voltage fitting, so a couple of major differences really. Obviously just a MWC though!

Anyway... No RCD required, quick MWC, Bobs your Uncle :smile5:

So you have included my quote but none of what you have put seems to relate to it

 

[telectrix]

i'd provide a mwc, even if it's just a cma.

 

[happysteve]

[edit: I meant to quote Murdoch here, but I must've had a senior moment and accidentally quoted Tel...]

I wouldn't say it's pointless, Murdoch. I've learnt summat

I've been under the misapprehension that if you make an addition or alteration to a circuit, then you have to ensure that the circuit complies to the current regs, not just the alteration.

So HHD's case is a good one. Changing a light switch on a non-RCD protected circuit where cables are buried in plaster, my previous understanding would be that you have to make sure the rest of the circuit complies... in the same way that you take the maximum Zs reading to make sure the circuit you've altered meets disconnection times, which may not be at the bit of the circuit you've altered, but is most likely at the furthest point (old cabling).

I guess part of my confusion comes down to the example MEIWC in GN3 (p101 of the old green "17th+A1" version) where, in the example, "Comment on existing installation..." says: "Existing circuit is not provided with additional protection by RCD. Lighting circuit MCB converted to RCBO in order adequately to provide protection against damage to cables in walls; Reg. 522.6.101 refers." I took this as "you should do this" rather than, "here is an example of something you could do."

I guess 610.4 is pretty clear: "For an addition or alteration to an existing installation, it shall be verified that the addition or alteration complies with the Regulations and does not impair the safety of the existing installation," (my emphasis).

Every day's a school day. Thanks all.

 

[NDG Elecs]

i'd provide a mwc, even if it's just a cma.

Have Googled it and still none the wiser... Guessing it isn't crystal methamphetamine or calculated malware attack.... Something maintenance something!! Go on Tel give us a clue please and put me out of my misery!

 

[Richard Burns]

cover my ....?

 

[telectrix]

yup. cma... cover my arse.

 

[NDG Elecs]

Aaaahh!! That makes sense.. Thank you. MWC or invoice with Zs as a minimum on it for me. Depends on the property and the client.

 

[andyb]

Dave the DIYer wouldn't so why should we?

Because we're electricians Murdoch.
I agree with all you say up to this.

I tend to fill out a mwc on all jobs now even like for like, with just the relevant info recorded. In this case no IR, but Zs, ocpd, installation details plus whatever.

 

[HappyHippyDad]

Because we're electricians Murdoch.
I agree with all you say up to this.

I tend to fill out a mwc on all jobs now even like for like, with just the relevant info recorded. In this case no IR, but Zs, ocpd, installation details plus whatever.

So why wouldn't you measure the IR Andy? Is it because you're only responsible for the bit you have added so it is obvious that the IR will be ok?

 

[NDG Elecs]

So why wouldn't you measure the IR Andy? Is it because you're only responsible for the bit you have added so it is obvious that the IR will be ok?

Hi Happy,

If I was changing some light fittings over, which is what you have basically done, I would class it as maintenance. What would you test if you changed a light switch for instance? If nothing within the installation raised any alarm bells when I was swapping things over I would see no reason to carry out much more than a Zs and, if TT test the RCD. Depending on the client I would offer full testing but most want their shiny new light up cheaply.

I used to fill in a MWC religiously and after a couple of years I remembered I am not at all religious!!! I take my chances maybe but so be it. A high Zs or any other issues then the client would be informed in writing. Being self employed I don't encourage excessive paperwork!!

The IR may not be ok as you point out, but i suppose we gotta draw the line somewhere. Tin hat at my side!!

 

[Paul.M]

I will be changing some ELV downlights to GU10 fittings and wondered if I needed RCD protection? I cant see why as I wont be burying the cables and its not in a special location but just not 100% sure, especially with amd 3 just arriving.

You are not changing the characteristics of the "circuit" only the load. Check what load was on the circuit in total at first and what you are proposing to change it to? Are the cable and mcb acceptable to your changes? If so just carry out a Zs at the end of line to confirm an earth return path before you start. Ze + bonding checks as per normal. Anything beyond that is to "CMA" via a MWC as said above. If you want to spend all day giving the circuit a full EIRC feel free, I would'nt!