TT 16 Edn, do I need to RCD the lights when I work on RCD side circuits?

[1Justin]

Hi, Sorry to re-cover stuff which might be previously thrashed but after trawling about I can't find a specific answer.

Work on domestic TT system which contains 16th edition board (ie lighting without RCD, sockets and other circuits all on 30mA RCD side).

Lighting/non RCD side will contain concealed unprotected wiring in walls, but it will very likely all be in zone due to the age and history of house.

I need to install one new circuit on the RCD protected side.

Is it sufficient for me just to recommend to the customer, and write in EIC, that the non-RCD side (lights) ought to be upgraded to RCD? - Hence leave to 16th ed'n board as it stands.

- Or having worked on the board (albeit only the RCD side), am I responsible for the lighting side of the installation and must upgrade this side to RCD, even though I would not otherwise be touching it or needing to test any of the lighting circuits?

 

[telectrix]

the work that you do must comply with current regs. previous parts of the installation don't have to be upgraded.

 

[1Justin]

Thanks Telectrix. That was the way I presented it to the customer, only I don't do much on TT, and it would give me the wobbles to leave it that way. However my recommendation was fairly firm. Provided I'm absolved of responsibility by so doing, I'll see what they say and take it from there. Rgds

 

[tony mc]

Is there a 100mA s type protecting the premises?

 

[1Justin]

No 100mA s type. The 16th ed'n board was installed as though it were a TN . - I'm not familiar with 16th ed'n, but was a 100mA main switch a requirement then for TT?

 

[tony mc]

When you do your Ra test I bet you find the non RCD side of the board will not comply with the disconnection times and I would be strongly recommending that a 100mA time delayed unit be placed on the tails ! The following still had to be fulfilled in the 16th Ra Ia <or equal to 50v.

 

[1Justin]

Thanks Tony, so it was in 16th also Hmm. In that case it's always been wrong. And I strongly believe it won't pass the disconnection times on the lighting side.

 

[nottz_spark]

Thanks Telectrix. That was the way I presented it to the customer, only I don't do much on TT, and it would give me the wobbles to leave it that way. However my recommendation was fairly firm. Provided I'm absolved of responsibility by so doing, I'll see what they say and take it from there. Rgds

like yourself i have limited TT experience so i'm interested in this, my point is that we often have to make the final call and we have to be careful to always be sure dangerous situations are addressed appropriately so i respect you by seeking confirmation on here from more learned members, i think you have done what you could be reasonably expected to do and as long as its in writing on the cert you are covered legally and more important morally.

 

[Outspoken]

Hi, Sorry to re-cover stuff which might be previously thrashed but after trawling about I can't find a specific answer.

Work on domestic TT system which contains 16th edition board (ie lighting without RCD, sockets and other circuits all on 30mA RCD side).

Lighting/non RCD side will contain concealed unprotected wiring in walls, but it will very likely all be in zone due to the age and history of house.

I need to install one new circuit on the RCD protected side.

Is it sufficient for me just to recommend to the customer, and write in EIC, that the non-RCD side (lights) ought to be upgraded to RCD? - Hence leave to 16th ed'n board as it stands.

- Or having worked on the board (albeit only the RCD side), am I responsible for the lighting side of the installation and must upgrade this side to RCD, even though I would not otherwise be touching it or needing to test any of the lighting circuits?

Justin, have you absolutely confirmed the installation is still a true TT? I have known many over the years that have been upgraded to PME systems by the DNO but the earth spike remains in the ground (not an issue) I would suggest you take some readings to see what the R[SUB]A[/SUB] is as it may be compliant and there is no need for the Type S at the front end.

Clearly if the system is a true TT then you are required to ensure the installation meets the requirements for disconnection times because even if you are only working on a circuit to be RCD protected, you have a legal and moral obligation to advise the client they require the main switch to be upgraded and possibly the main earth too..up to them if they accept it though as they need to pay for it.