Replacement consumer unit necessary?

Thank you all for your help. I will advise my son to tell the builder that he doesn't want a new consumer unit but a type A RCD can be fitted into the existing consumer unit.
 
Sponsored Links
Or even better tell the builder you will sort the electrical side of things and get someone who doesn't need your advice.
 
I'd be interested to know how far you go in interpreting new regs that apply to new work (or 'new circuits' etc.) also apply to all aspects of existing circuits (or whatever) if they are extended/modified.
It will be interesting to see what the builder says when he is told that the new consumer unit isn't wanted. My son won't mention the RCD type, he will wait to see if the builder/his electrician mentions it.

Although I cannot change the consumer unit without getting building control involved, I suppose that there is nothing to stop me changing the RCDs in the existing consumer unit? I have access to test equipment and know how to use it. I've done lots of industrial electrics in the past as an electrician's mate but no domestic electrics outside my own home. There is an isolator between the meter and the CU so I wouldn't need to interfere with the DNO cut out.
 
Sponsored Links
Or even better tell the builder you will sort the electrical side of things and get someone who doesn't need your advice.
We might have to do that. It is convenient for the builder to do all of the work in a co-ordinated way as my son has only one bathroom and toilet. Will wait to see what the response is to not having a new CU.
 
We were told around 2004 that any socket likely to be used outside should be RCD protected, so yes the spark should look at what is likely to be used.

I do have a metal consumer unit, however my isolator is in a plastic box, and my meter is plastic and the DNO fuse carrier is plastic, so really no point.

I have seen the problem, a consumer unit was ordered together with the overload devices and for convenience the lad at the whole sale outlet slotted the MCB's into the box, however the electrician who picked up the box, thought it was a ready populated box, he should if following instructions have tested all connections for tightness, but he only torqued up the connections he had made.

Lucky this caused the phones to play up, so was found before any heavy load was put on the circuits, but it could have caused a fire.

However had all the MCB's been in a faraday cage of a metal consumed unit, then it may not have upset the phones, so could have caused a fire.

But it is like when there is a motor accident due to some one doing 60 MPH in a 30 limit, lowering the limit to 20 MPH. It cures nothing.
 
I suspect that there might be some debate about "or extended circuits".
No reason for that, BS7671 110.1.2 (vii) is perfectly clear.

I'd be interested to know how far you go in interpreting new regs that apply to new work (or 'new circuits' etc.) also apply to all aspects of existing circuits (or whatever) if they are extended/modified.
There is no interpretation.
Additions and alterations to circuits need to comply with BS7671. That includes protective devices for the circuit.
if the RCD is the wrong type, it is changed. Just as if an MCB was the wrong rating, it would be changed. Or if a rusty nail had been used instead of the appropriate fuse, that would be changed.
 
For example, would you say that installing a new circuit in a spare way in a CU invokes the need to replace (or enclose) the CU if it is plastic?
No.
An enclosure serves the same function whether it is plastic or metal.
If parts are available for it, and it's in good condition, an additional circuit can be added.
 
Any 'DC leakage' is entirely down to whatever is plugged into the socket outlets, and there will nearly always have been plenty of them even before 'the work' was undertaken, even if that work involves increasing the number of socket outlets.
With that flawed logic everyone would still be using live front switchboards and rewireable fuses.

The difference between Type AC and Type A is not due to 'DC leakage'.

Type A will operate with non-sinusoidal current, which is what the majority of electrical equipment in use today creates.
Type AC were designed for sinusoidal current waveforms. Their operation with other waveforms is undefined and mostly unknown.

For circuits that do have a possibility of DC current or higher frequencies, other types of RCD will be required.
 
And then there is the thorny issue of so many sparks unable to actually test type A RCDs
 

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
Back
Top