RCD Hell

Help required...

Guys an Gals

I have just had a new Wylex split load CU installed by a local sparkie. Since then, two problems have occurred that he is struggling to resolve.

The first one being;

As soon as the upstairs Ring is connected to the RCD protected side of the CU the RCD trips.

In all fairness, he is yet to start troubleshooting this one. Thus has moved it over to the non RCD protected side of the CU.

The other more pressing issue that needs to be resolved is this;

Whenever one of two light switches are pressed, one being a two way switch in the hall the other being a one way switch in the kitchen, the RCD trips. The lights are NOT on the RCD protected side of the CU. Which I believe is normal practice. But the downstairs Ring for the sockets are... Therefore, how would the two relate to each other unless there where to be an inter connection between the two circuits.

So far the electrician has advised that we remove the bulbs from the two offending lights which resolves the issue.

We are expecting a visit this coming Saturday for some extensive troubleshooting. Therefore, if I can get some ideas in the mean time I might be able to help him out and also reduce my bill.

I am not an electrician or even pretend to be, so if I have misinterpreted any of the above please do not be offended.

Answers and suggestions greatly appreciated.

Cheers.

Reply to
diynovice
Loading thread data ...

If it trips the moment it's connected, with no load, there's likely to be a neutral-to-earth fault on the ring wiring. If it trips once there's a load, he's probably got the neutrals connected to the non-RCD N busbar.

It's possible he's wired the N for these lights to the RCD N, while taking the L from the non-RCD side; but not if there are other lights on the same circuit which don't pop the RCD. Other possibilities include a 'borrowed' neutral for these lights (some previous mumpty's used a 'handy' connection to a nearby socket to take the N).

No - but your "local sparkie" is pretending to be. These are not massively subtle faults we're concerned with here, and a bit of logical thought and a meter should be all a real sparkie would need. Relying on an existing installation to be up to scratch is naive, and your sparkie should've been testing each final circuit before connecting it to the new CU. By the sounds of it, he's replaced like-for-like, possibly got some of his N cores muddled, and (if I understand your "help him out and also reduce my bill" comment), expecting *you* to pay for his incompetence. So, when you say,

- we're not offended, but you should be, at your 'sparky's' antics. But they're probably entitled to self-certify under Part-Prescott-Takes-The-Pee, so that's alright then: good ol' 'Two Fuses' (or was it 'two planks'?) keeping us all safe...

Stefek

Reply to
Stefek Zaba

It's likely that the cretin who originally wired your house decided to borrow neutrals left right and centre. A borrowed neutral from the RCDed ring main used on the two way lighting would cause these issues. Anyone cretinous to devise such a system is quite capable of a whole load of faults. I would do a complete test of the entire installation, checking ring continuity, insulation resistance (you've may have a neutral-earth short in there somewhere) etc.

Christian.

Reply to
Christian McArdle

I'd just say that any sparks worthy of the name would have tested an existing ring before connecting it. Just because it 'worked' before on a fuse protected circuit doesn't mean it will be satisfactory for an RCD protected one. For example, both neutrals have to go to the correct 'RCD' busbar - where before there was only one.

Reply to
Dave Plowman (News)

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.