RCD for outdoor public Car Park high mast lighting

gkenyon

This is really helpful, thank you.

Each steel lighting column will have a cut-out containing live conductors at an accessible height, but it will be housed within a locked enclosure. Based on that, is it correct to say that, provided I can confirm the lighting columns are IK08 rated, the 30 mA RCD requirement can be omitted? Does that sound like the correct approach?

Gyaneshwar Kumar said:

provided I can confirm the lighting columns are IK08 rated

lighting columns and and any other enclosures used for the lighting installation that are accessible to the public would need to be IK08.

There is a slight technicality ... I get the impression the project is being executed under an earlier version of BS 7671 (perhaps BS 7671:2018+A2:2022 with or without Amendment 3:2024). If this is the case, technically it's still not fully conformant to the earlier version of BS 7671. There are a couple of issues which might need to be resolved (on paper) dependent on the contract:

• Agree 'intended departure' to use BS 7671:2018+A4:2026 for this particular issue (or the whole project).
• Decide how you will issue a statement regarding a potential departure if you are still to certify to an earlier version of BS 7671.

Or ... agree with the Client (and document on CDM risk register) that everyone agrees to the 'interpretation;' provided in the 2026 version.

FINALLY

If this is in the UK, the CDM Regulations require a designer to consider risks associated with a construction project, for commissioning, maintenance, and, if a place of work, in use. Whilst BS 7671 might not require an RCD for a particular circuit, are there any residual risks in commissioning, maintenance and in use, that an RCD would mitigate?

Thanks a lot. Makes sense! 

Yes the site is in the UK. As this is for a private network, the contract is not binding to any BS7671 version but we aim to be compliant with the latest version unless there is a good enough documented reason to take a departure. There is nothing else as per risk assessment for these circuits that would necessitate employing RCDs. Infact all the existing flood lights and lighting columns on site do not have any RCD protection likely because they were installed before BS7671:2018 +A2 which is when I believe this ambiguous requirement was added. Glad that it is clarified in the 2026 version. Thanks again for your help. Much appreciated. 

Gyaneshwar Kumar said:

which is when I believe this ambiguous requirement was adde

There is a very good reason for the requirement:

https://www.bbc.co.uk/news/uk-england-london-56758749

Thanks, yes, I was aware of this unfortunate incident. There are certainly situations where an RCD is required. My uncertainty was around what exactly is meant by “publicly accessible lighting,” as the definition wasn’t entirely clear. And as you said BS7671 not requiring RCD is not a good enough reason to not provide one if the risk assessment dictates that. 

There is a very good reason for the requirement:

Although, from the reports, it sounds rather like the problems was lack of basic ADS - if that had been done properly the lack of 30mA RCD might have been mute. Likewise if you can't trust 'em to get the basics right, what chance they'll comply with the latest regs add an extra RCD (and exercise it often enough that it can be relied on when needed)?

Still I suppose there's a chance that in the case of some future hacked bodge to a properly installed circuit, the RCD might avert another tragedy.

   - Andy.

AJJewsbury said:

if that had been done properly the lack of 30mA RCD might have been mute

I don't follow. RCDs not exceeding 30 mA are intended for additional protection. Additional protection is specifically intended for protection in the event of failure of:

• basic protection
• fault protection
• carelessness by users

(See Regulation 415.1.1 of BS 7671.)

AJJewsbury said:

Likewise if you can't trust 'em to get the basics right, what chance they'll comply with the latest regs add an extra RCD (and exercise it often enough that it can be relied on when needed)?

Agreed.

I don't follow

What I was trying to get at was (if my reading between the lines of the reports is right) the fundamental problem was lack of earthing/ADS - and if that had been got right the poor boy almost certainly wouldn't have died in those circumstances, RCD or no RCD. By all accounts it wasn't that some fuse failed to blow, an MCB that failed to trip, or gradual deterioration of a c.p.c. but basic lack of good workmanship at installation time.

For sure an extra layer of protection might have weighted the odds a bit more - but where do you draw the line? - open PEN detectors next? 

  - Andy.

I don't follow

What I was trying to get at was (if my reading between the lines of the reports is right) the fundamental problem was lack of earthing/ADS - and if that had been got right the poor boy almost certainly wouldn't have died in those circumstances, RCD or no RCD. By all accounts it wasn't that some fuse failed to blow, an MCB that failed to trip, or gradual deterioration of a c.p.c. but basic lack of good workmanship at installation time.

For sure an extra layer of protection might have weighted the odds a bit more - but where do you draw the line? - open PEN detectors next? 

  - Andy.