Urgent question re. RCDs

[Sniffy]

I have an electrical problem in my flat which developed this evening and was noticed by myself about 5 mins ago - could do with some guidance on possible causes please.

The lights started flickering, this became worse over the course of about 30 mins. I then had cause to go into the hallway where the RCD cab is located and noticed an acrid burning smell. I could also hear an arcing sound from the RCD cab. Flicked off the lighting RCD whilst leaving everything else on, and the problem's gone (I just have no lights!).

I imagine I need to whip off the cover and replace the RCD but is that it, or could there be an underlying fault that's sent it faulty to start with? I have a fairly standard set up, only thing unusual I suppose is a touch controlled dimmer switch from intelliswitch.co.uk.

Also, am I allowed to buy a new RCD module and change it, or does the law say I have to get a sparky in? TIA

[r.p.mcmurphy]

could be just a loose wire. get a torch and switch everything off and have a tug on the wires....DON'T touch the big black wires coming into the box from the main fuse!

steve

[malcolm gray]

When my consumer unit did this it turned out to be a loose neutral where they were all commoned toegther.

[Sniffy]

Ok, that's a couple of votes for a loose wire, which sounds feasible although nothing's been connected or disconnected in there for at least a year, so I don't know why a wire would become loose now.

Anyway, I'll have a look tomorrow when (a) it's daylight and (b) I'll be sober..!

Incidentally, and by way of a recommendation, this evening I've been discovering the value of a mains rechargeable floorstanding halogen lamp unit I bought last year. Nearly binned it as a "useless" impulse buy, but right now it's my only lights and it's moving around my flat with me.

[Matt]

....or the red blue or brown ones.

[John Rumm]

I assume you mena MCB (i.e. circuit breaker) rather than RCD?

It could be...

Could also be a loose wire into it - possibly even a loose connection at the other end of it to the live busbar

If you care, opening the consumer unit probably comes under part P these days.... However you will have no difficulty getting a fitting a replacement so long as the CU is not some very obscure make (the MCB does not even have to be the same brand as the CU in every case)

[Dave Plowman (News)]

I imagine you mean the Consumer Unit (CU) and you flicked off the lighting MCB? An RCD as such doesn't protect against overload, and there's usually only one per CU.

If there was a smell of burning it's likely a poor connection, and the wiring may be damaged too, but this should be fairly obvious with an inspection. I'd also check all the other connections inside the CU are good and tight after fixing this fault. Best to isolate the CU before doing any of this by pulling the main incoming fuse if there isn't an external isolator.

[Fred]

"> Anyway, I'll have a look tomorrow when (a) it's daylight and (b) I'll

Are you still with us?

[Sniffy]

Heh, I am indeed, but I need another beer. I've whipped the cover off the consumer unit and not liked what I found:

the MCB on the LHS is the one I switched off yesterday and thought I'd isolated the problem with. Having looked at it today though, I can see the burning is on the Neutral bar and affects a number of feeds.

A few of the screws for the return feeds onto this bar were semi-loose and have now been tightened. I don't like the state of things in there though and believe it will need sorting out.

Does anyone know what an electrician might charge for a small job like this - alternatively is it easy enough for a clumsy idiot like myself?

[John]

On the good side the problem is downstream of your main isolation RCD so when this is switched off you are safe to work on it (Don't touch the thick incoming supply wires or terminals). On the downside you dont sound very confident and the casing might be distorted by the burning so replacing the terminal bar might not be an easy job. You will definitely need a replacement Neutral bar or rail and a replacement neutral link (the bit of thick wire with the burnt insulation and the crimped end attached). If the casing looks sound then take the make and model details to a decent electrical wholesaler in your locality and obtain the parts. Once turned off changing them for new is a simple Meccano job. You may need to cut back the ends of the rest of the Neutral wires to get rid of the burnt bits and reterminate. Note that they "should" terminate in the same order as the corresponding lives appear in the MCBs. If you aren't happy then get a pro in.

[Matt Beard]

This seems to be a great example of why possible electrical faults shouldn't be treated with the response "It seems to have stopped now - must take a look some time".

Modern CUs are, I believe, made of self-extinguishing plastic and the PVC insulation does not burn all that well, so I don't think a fire was as big a risk as it looks - but it would still give me sleepless nights if I found that in my home!

[Sniffy]

Yes, you're correct.

[Sniffy]

Thanks for the advice, I think I will tackle it myself. As you suggest, I'm not especially confident with electrics ever since I got a bolt from a lightswitch. That said, it does seem fairly straightforward and with the main switch off it should be safe.

There's a City Electrical Factors in Slough - does anyone know if they'll do a cash sale to a member of Joe Public? I think I'll print the photo and take it so I can point at the bits I want. Might make me look like a numpty but at least I'll have a change of ending up with the right bits.

[Sniffy]

Tbh I was contemplating leaving it, as now the terminals are tightened it seems the situation shouldn't deteriorate. On balance though, the possibility of disturbance to sleep will pursuade me to sort it.

[Tony Eva]

Dunno anything about City Electrical Factors, but there's a branch of TLC

in Slough which has always been very helpful to me, and very willing to sell for cash or card to Joe Public.

[Keith]

CEF up my way welcome joe public with open arms and are extremely helpful and knowledgeable.

[tony sayer]

In article , Keith writes

And the girl in WF electrical in Cambridge, you'd love to have her in your open arms, a good few BSH's :)...

[ARWadsworth]

It could be that simply cleaning everything up

Is "groan" a torque wrench setting? Most CU's have a Nm rating for their busbars which depends on the cable size into it. I was gobsmacked at how low they were after I bought my torque wrench.

The neutral link could be replaced with the correct cable for a few quid if needed.

I could not agree more. The factory set terminals are usually not tight enough on the Volex, Crabtree and Wylex range.That is probably because they are all made in the same factory.

Adam

[Andy Hall]

Bosch und Siemens Hausgeräte ?

[tony sayer]

In article , Andy Hall writes

No, a British Standard Handfull :)....