More RCD issues

[GForrow]

Thanks again - B & Q don't do RCBO unfortunately, although I may pop in as they may not be on web. My local MK screwfix only does curve C.

I can't find too many local wholesalers, so maybe time for yellow pages, and then find one who does private sales.

I'll get there

Gary

 

[ColJack]

I don't know a wholesaler who doesn't do counter sales..

 

[GForrow]

Checked a few that I could find in my area that had working wesites.

Screwfix - Curve C only.
CEF - Don't do Wylex on the web
Neweysonline - Curve C only

Anyway will dig yellow pages out tomorrow and try and find a reputable supplier, of Curve B.

Cheers

Gary

 

[securespark]

You said right at the beginning about turning off MCB's to try & isolate the fault. It may be a neutral/earth fault, in which case isolating the MCB's will not isolate the fault....

Did the geezer who tested the install leave you any figures?

RCD test times, ramp test & IR would be good to look at...

 

[GForrow]

Nope nothing, but then I wasn't paying him, the builder was under the warranty, now expired.

I have narrowed it down to one of the three rings, the two for each upper floor, or the kitchen one.

It isn't the garage one, it isn't the cooker one. It isn't pc gear, there is nothing left to unplug and wait.

Therefore I have decided to use an RCBO for the kitchen ring, and then narrow down from there. Of course putting another 30mA trip in there may stop the problem anyway, if something was just pushing the RCD over the limit.

Gary

 

[GForrow]

Well that didn't go as well as expected, I must get another electrician.

RCBO Type B was purchased yesterday, and my man popped round for half an hour, and the obligatory cup of tea to install it.

Half an hour later, he has to go, I knew he was time limited, and the wiring is back to how it was.

For some reason after connecting the RCBO, and replacing the wires for the kitchen MCB into the RCBO and powering on, the RCD tripped, and the RCBO, now on the non protected side wouldn't stay on, Doh!

Queue head scratching - and a quick exit. Hopefully he can fit me in again soon, but who knows.

Looking at the RCBO myself, it doesn't look difficult, a connection to the busbar at the bottom, and a live out, neutral out at the top. There is also a fly lead for the neutral in, and an earth lead. Seems straight forward to me. Disconnect the lives from the MCB, and stick them in live out. Stick the neutrals from the same cables into the neutral out, connect the fly lead to the neutral bar, and the earth to the earth bar, and switch on. However, I am not going in there messing by myself, I know of the regs or can I do this myself and then get it checked and signed off. surely as long as I find the right neutral to go with the lives from the MCB, I cant go wrong? or can I?

I guess if it were that simple then we would all be experts. Hopefully he can come back next weekend, with more time, I hope.

Gary

 

[ColJack]

ok, stupid question time..
did he move the neutrals over when he installed it or just the lives?
did he put the neutral flylead on the UNPROTECTED neutral bar?

 

[GForrow]

Yep - the neutral fly lead to the neutral bar at the top.

The nuetrals that went with the lives to the RCBO. No good. However, the builders have stripped the insulation well back on the cables, so its possible they were the wrong neutrals. I think next time, it will be time to ensure they are the right neutrals . They looked like it, and were together on the neutral bar, but hey, thats what comes of trying to rush things.

I may have a dive in there tomorrow, depends how brave I am feeling. I, as a Layman, found it odd though that the RCD was still tripping, despite the RCBO being before it. Perhaps that signifies the wrong neutral then.

Thanks for the questions, helps clear things up in my mind, although I am no further forward than this morning, or in fact from 2 years ago.

Gary

 

[ColJack]

which neutral bar at the top? is there only 1 or is there 2?
if it's a split load board then there should be 2..
one for protected and one for non..

if you've added an RCBO to the non protected side, it's neutral should go to the non protected neutral bar..

 

[GForrow]

I'll have a look and see. There were two neutral bars but I'm sure he checked and there was continuity across them indicating what looked like a break was just the box moulding. If I take the cover off today then I will take a picture.

Gary

 

[GForrow]

Success I think.

This morning I got my DIY hat on and tried to install the RCBO myself. Turned everything off, unplugged everything on the kitchen circuit. Removed the two lives from the MCB, found the corresponding neutrals, and reconnected those to the RCBO. Connected the neutral flylead to the neutral bar, corresponding to the non protected side, and then the functional earth lead. Whacked it on to the spare terminal on the busbar, tightened everything up, and flicked the switch.

Turned on the RCD, great, turned on the RCBO great. Started to plug everything back on to the kitchen circuit, and it all stayed live, and no tripping.

I turned it all off again, checked everything was tight, put the cover back on and turned it all back on again, and it works, happy as Larry.

I can only think yesterday it was connected to the wrong neutral bar, but not today. I will get it checked and signed off if I have to, still need to look into that one in detail. Probably because I have changed the protection system I will, but will confirm.

Thanks for all your assistance chaps, hopefully I won't be back saying it's tripped again, but if it does I'll have a better idea of which circuit it is.

Gary