RCBO: CU or in-line?
- Thread starter Inchiquin
- Start date
Sponsored Links
That is true.
However, what is the OP supposed to do if he wants to (and presumably should/must) fit an RCD to cover his work?
I suppose an RCCB would be an equal amount of work.
He could use an RCD FCU, https://www.screwfix.com/c/electrical-lighting/fused-spurs/cat13020004?withrcd=rcd ,but that would also have an unnecessary fuse in it. He could fit a 13A fuse so that the MCB in the consumer unit would trip before the fuse blows (likely with a 3A fuse anyway).
What about a 16A or 32A RCBO to achieve the same? A bit silly?
Also someone will say, mistakenly due to misreading the regulations, that he cannot have an RCD FCU without also having another RCD upstream in the consumer unit.
However, what is the OP supposed to do if he wants to (and presumably should/must) fit an RCD to cover his work?
I suppose an RCCB would be an equal amount of work.
He could use an RCD FCU, https://www.screwfix.com/c/electrical-lighting/fused-spurs/cat13020004?withrcd=rcd ,but that would also have an unnecessary fuse in it. He could fit a 13A fuse so that the MCB in the consumer unit would trip before the fuse blows (likely with a 3A fuse anyway).
What about a 16A or 32A RCBO to achieve the same? A bit silly?
Also someone will say, mistakenly due to misreading the regulations, that he cannot have an RCD FCU without also having another RCD upstream in the consumer unit.
As I've been suggesting, I don't think they would be 'mistaken' if some of the cable between CU and RCD FCU were 'buried', would they?
Kind Regards, John
Not if it were new - but do you think existing wiring would require it because a new light or fan is fitted on the end.
Sponsored Links
Opinions seem to differ about that, and there doesn't seem to be any explicit guidance.
Some seem to believe that if a circuit is modified/extended/whatever, then it becomes necessary for the whole circuit to comply with current regs. From what you've written, do I take it that you do not have that view?
Kind Regards, John
I do not hold that view.
Although, as seems to be the case here, if RCBOs are available for the existing CU, then one might as well fit one.
If that were not the case, it would surely be wrong and silly to say that an additional light cannot be fitted without replacing the CU.
Although, as seems to be the case here, if RCBOs are available for the existing CU, then one might as well fit one.
If that were not the case, it would surely be wrong and silly to say that an additional light cannot be fitted without replacing the CU.
Quite so. One might as well afford 'currently required protection' to the entire circuit. The OP's idea of using an RCBO just for the new work because it would be marginally cheaper than an RCBO for his CU seems pretty trivial.
Dunno - as I said, some people seem to believe that changes/extensions to a circuit require the whole circuit to be brought into compliance with current regs, and I'm not sure that I would necessarily regard that view as 'wrong and silly'. As always, if the regs (or even 'guidelines') clarified this issue, there would be no need for debate or differing views.
As things are, there may sometimes be a need for 'judgements'. Is there any limit to how much extension/modification of a circuit is required before you feel that the whole circuit needs to be compliant with current regs? What if a circuit is 're-purposed'?
Kind Regards, John
,.
If new work must conform to the latest regulations, and the regulations are not retrospective, then it stands to reason that the existing does not have to be updated.
That's obviously one view - but, as I said, there is no real clarity about this in the regs.
This "not retrospective" argument, which we all often use, is not really all that straightforward. What the regs actually say is that work compliant with previous editions of the regs (but not compliant with current ones) is "not necessarily unsafe ... or need upgrading" - which is a pretty weak statement (and, indeed, seems to imply that it may "be unsafe .... or need upgrading").
Kind Regards, John
That requires updating - RCDs have been required for most socket outlets for over 30 years.
Today almost everything requires RCDs, including cables in walls, all socket outlets, lighting circuits and various others.
Very true, in terms of current regulations - hence my earlier comments in this thread.
However, per what EFLI is arguing, how much extension/modification (maybe 'unlimited'?) to an existing circuit do you feel has to happen before there is a regulatory requirement for the entire circuit to be brought into compliance with current regs?
Kind Regards, John
If it was just replacing an existing item, such as a fan or light, then not required to update the circuit.
If it's replacing something which manufacturer's instructions state that an RCD is required such as an electric shower, then the whole circuit is upgraded.
Where wiring is added/altered and items are installed that didn't exist before, RCD is required.
In the OPs case, what they are adding certainly requires RCD, and although adding a separate RCD is an option, it's rather pointless. Installing an RCBO for the whole circuit would be far better.
As their consumer unit is either pre-1991 or didn't comply when installed, strongly recommended to have that replaced.
If it's replacing something which manufacturer's instructions state that an RCD is required such as an electric shower, then the whole circuit is upgraded.
Where wiring is added/altered and items are installed that didn't exist before, RCD is required.
In the OPs case, what they are adding certainly requires RCD, and although adding a separate RCD is an option, it's rather pointless. Installing an RCBO for the whole circuit would be far better.
As their consumer unit is either pre-1991 or didn't comply when installed, strongly recommended to have that replaced.
Interesting - the second of those appears to be at variance with EFLI's view.
Do you mean RCD protection of the entire circuit, or just the new bits? If the former then, again, you view seems to differ from EFLI's.
Indeed - as you will be aware, I made that point at the very start.
Kind Regards, John
Some manufacturer's of showers correctly state that it is the circuit which requires the RCD; not the shower.
So, back to square one.
If the MIs say that, it's surely just a statement of what the current regs require, not anything to do with the requirements of their product, isn't it?
Kind Regards, John
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
