MCB help needed urgently please!

[David1983]

Good evening! I've been changing a socket downstairs and I've now not got any power to my downstairs sockets. On my consumer unit I turned off the circuit breaker marked 'sockets downstairs', took off the old socket and replaced it with a new one, like for like. Once I'd fitted it all I went back to the consumer unit to turn on the downstairs sockets, did that and now nothing.

The circuit breaker was very stiff so I had to give it a bit of a push back to on and now it doesn't seem to click going from 'off; through the horizontak to 'on' as the others do. Any ideas what's wrong as I'm stumped.

Thank you in advance!

 

[ban-all-sheds]

MCBs will behave how you describe if there's a fault, i.e. a short circuit, in the wiring.

Take the socket off and make sure the wiring is OK, nothing touching that shouldn't be, nothing pinched when the socket is screwed into place etc.

 

[David1983]

Hi, I've tried taking the new socket off, checking the wiring and starting again. I can't see any problems with the wiring, all the insulation is present and nothing appears to be pinching.

Could it be that I've broken the mcb when I've turned it back on - it was quite stiff and now there's a lot less resistance when I turn it off or on.

Am I right in thinking that if there was a short circuit or other fault that the mcb wouldn't stay in the on position but that it would trip to the off position?

If it makes any difference, my mcb stays in the on position. I'm still baffled though!

 

[RF Lighting]

Do you have an RCD in your consumer unit? Has that tripped?

Have you tried pushing the MCB all the way to off before pushing it back to on?

What make is your CU?

 

[David1983]

My consumer unit is a MEM Memera 21. It has got an RCD and that has not tripped. I have also tried pushing the MCB all the way to off and tried pushing it all the way to on again, no joy whatsoever. An electrician friend is coming tomorrow afternoon to have a look but over the phone he thinks that it may just be that the cb has broken. He's going to have a look at the socket too mind, in case I've doen something wrong. In the meantime any suggestions are very much appreciated!

EDIT: I can get a new MCB (321 QEB) from a wholesaler tomorrow for £32 or a used one from e-bay for £5, would it be more sensible to get a new one that I know is genuine etc... What is the professional view?

 

[RF Lighting]

I'd wait and see first.

£32 seems rather expensive, even for a discontinued MCB.

It does sound a little odd how your MCB is behaving.

 

[David1983]

From what you've said the only thing I can think of is possible pinching when the socket's screwed on. I don't think it is but would it be worth trying with the socket unscrewed from the wall (still connected though) and then seeing what happens? Or is that just plain silly? What would your thoughts be on getting a used mcb from ebay?

 

[333rocky333]

With the main switch off, does the mcb feel better.

Why was you changing the socket, did something happen previous that may have affected the mcb.

 

[JonoPashley]

i personally wouldn't purchase a used mcb off ebay. Some people do but to me its not really worth the risk factor of it not working or having any other faults/damage.

have the wires been pulled and possibly sliced on the back box or maybe even pulled out of a junction box below the floor?

 

[David1983]

I was changing the socket because the previous owners painted the hall, and most of the socket, mustard yellow and I'm redecorating. It didn't appear to be damaged in any way, just mostly a hideous yellow!

The MCB doesn't feel any different with the main switch on or off. I don't think that the wires have been pulled out of the junction box or sliced on the back box. Just in case they have been, how would I find out? I was going to avoid the ebay mcb due to the risk, just wantde to know the thoughts of professionals. Thanks!

 

[ban-all-sheds]

From what you've said the only thing I can think of is possible pinching when the socket's screwed on. I don't think it is but would it be worth trying with the socket unscrewed from the wall (still connected though) and then seeing what happens? Or is that just plain silly?

No - not silly.

Neither is trying it with the socket removed

BUT - make sure the ends of the cables are safe, and make sure that there are no heavy loads on the circuit, because if it does all come back on you won't have a ring.

The other thing you could try is to move the upstairs circuit onto the breaker (I assume you have one, on the same RCD). If it turns on OK then you can be sure that the fault does lie on the downstairs circuit.

OTOH, as you've got an electrician coming tomorrow, just have a few more glasses of red.

Let us know what he finds.....

 

[David1983]

I'll go and try it with the socket removed from the wall in case there is pinching and I could try swapping the upstairs MCB for the downstairs one but I don't feel happy opening up the consumer unit - I'm going to leave that to my friend who knows what he's doing. The only load on the circuit would be a lamp, to prove that the MCB is actually 'on'. Thank you all for your advice tonight and I'll let you know what was we find tomorrow. Thank you and goodnight!

 

[baldelectrician]

It's quite a common fault with these MCB's
They have a high failure rate nowadays.

You should use a competent person for the work, links below

In Scotland:
Individuals registered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/SearchCo.asp?T=Construction&ID=2

In England and Wales:
http://www.competentperson.co.uk

 

[Johnmelad502]

Just a thought, try putting the old socket back, see what happens. It could be that the new socket is the problem.

Like I said, just a thought.

 

[David1983]

Good afternoon! Finally the problem is fixed and I'd like to say thank you to everyone who posted advice and thoughts. Thank you.

I tried putting the old socket back on, there was still no power. When my electrician friend came he suggested we try the upstairs MCB (known to be working) in place of the downstairs one and the downstairs sockets worked. He put the new MCB on in place of the upstairs one (all 32A MCB). What he says has happened is the on/off switch on the front in no longer working and the MCB will be stuck in the 'off' position that I put it in to work on the socket.

So thank you all for your quick replies!