Earth leakage trip minor works

[Just]

Hi Looking at a minor works job in a flat, board which isn't split has a BS4293 RCCB as a main switch fed from an Earth leakage trip. I know both are obsolete and the SSC for the RCCB is 1500A. Am I right saying I can't just remove the earth leakage trip and replace the RCCB with a BS61008 as regs say rcd not allowed as main switch? Is this a board change? Cheers

 

[truckster]

Yep, you shouldn't have a single RCD covering the whole installation, possible exception would be a TT set up where you may have a delayed type upstream of the 30's

 

[Guest123]

Hi Looking at a minor works job in a flat, board which isn't split has a BS4293 RCCB as a main switch fed from an Earth leakage trip. I know both are obsolete and the SSC for the RCCB is 1500A. Am I right saying I can't just remove the earth leakage trip and replace the RCCB with a BS61008 as regs say rcd not allowed as main switch? Is this a board change? Cheers

The regs dont actually say that an RCD cannot be used as a main switch as it can be so.

Where you may fall foul is regulation 314.1 and minimising inconvenience in the event of a fault by having a single RCD protecting all circuits.

 

[SPARTYKUS]

Its not a new install though ... and you're only sanctioned to do what you're going to be paid to do.

So if they will only pay for you to replace an obsolete item with a new residual current circuit breaker, then thats what I would do.

You're not fixing the world but you're certainly making it better. I agree about 314.1 but that is in an ideal situation, this situation has presented itself.....

IMHO

 

[Guest123]

Its not a new install though ... and you're only sanctioned to do what you're going to be paid to do.

So if they will only pay for you to replace an obsolete item with a new residual current circuit breaker, then thats what I would do.

As would I.

IMO you are not making the situation any worse in terms of compliance as the arrangement already exists and some protection is better than none.

I was more trying to dispell the myth of "the regs say you cant use an RCD as a main switch".

 

[ezzzekiel]

pretty much just maintenance work and certainly not making the installation any less safe

 

[Just]

Thanks all, that's what I was hoping that I could replace the obsolete item so plan to whip out the ELT and replace RCD, which is an improvement on existing and perhaps advise that the old setup is not in accordance with regs having an rcd for main switch, but is now safe? I'll just note this on the MW cert under existing installation. I'm sure I won't get the job anyway, I find the hardest part of the job is quoting for a small job which others would do quickly and cheaply ignoring the existing installation. I know she has had quotes around £50 for an additional socket, and I've quoted for missing gas bond top floor flat and new rcd, remove ELT, so struggle to do it under £100. So it'll be another unsafe mod by someone. I know we can't cut corners to get the job but it would be good if we were all singing from the same song sheet. Thanks for your advice re rcd.

 

[BlueToBits]

Probably a bit late now but, if you are replacing a 500mA(?) device with a 30mA, it may be electrically "safer" but it is in direct contravention with 314.1 which was introduced specifically to protect against this sort of situation where the risk of injury and fire as a direct result of loss of light and power is greater than the protection the device offers in reducing electrical danger.
In other words, unwanted RCD tripping causes more accidents than it prevents by improving electrical safety.

 

[Just]

Hi Blue, no there is a 30ma BS4293 RCCB as a main switch in the board and an external ELT which I am going to remove. so just upgrade to 61008 in the board and remove the ELT. Not sure where you got 500ma from is that the earth leakage trip rating? Do you know the old BS number for ELT's? Would it be pre BS4293

 

[BlueToBits]

Nope, not particularly, Just that many of the front end RCDs I've come across of this era are 100-500mA. You didn't mention that it was 30mA which is why I question marked it. Like for like swap shouldn't be a problem.

 

[ringer]

I know that it only refers to a sub-board in a garage, but the IEE specifically state that you can use a RCD main switch in their guide to exporting PME in this thread. See the sentence at the end of page one, start of page two.