Possible faulty circuit protector

[Calculus]

I have never had to do anything on the distribution board other than reset a switch when something has tripped, but I have a genuine problem this time. First, some pics of the board:

The problem is the leftmost of that bank of four switched units (I'll call it no. 1). It tripped on Saturday and will not reset even after switching off all the sockets it serves and pulling out all appliance plugs.

I have managed to keep the household going by running extension cables from the sockets that run from nos. 2 and 4

First question is, what are these units? RCDs, MCBs or something else?

Second question is the fix. I have noticed the red switch on no. 1 feels spongy and doesn't click at all, suggesting it is faulty. Can I just pull the unit out and replace it with a new one? If so, what do I ask for at the electrical shop? And if I pull it out and take it to the shop, will that disable the other three?

This problem occurred intermittently a few years ago (no. 1 again) and I noticed it happened just after anyone had had a shower. I checked the silicone seals at the time and found they were lose. After I resealed the shower the problem disappeared. The seals look OK now but on Saturday I put Gorilla tape over them as a precaution. Two days have elapsed and the problem remains; I suspect it isn't the shower but can't be sure.

 

[davelx]

It's one of these (an mcb): https://www.tlc-direct.co.uk/Products/WYB32.html
They were a plug-in replacement for the Wylex standard range of rewireable fuses. High St electrical shops may not have them in stock.

Yes, you can just pull it out & replace it, BUT TURN THE MAIN SWITCH TO THE RIGHT OFF FIRST both when removing and replacing.
Removing it won't stop the others from working when you turn the main switch back on. Ensure that no little fingers can get anywhere near the unit whilst the MCB is not there (well, at all times, actually!).

However, it really is time that lot was replaced. In particular, I note that the (old) RCD only protects the 4-way unit. The 2-way one to the right seems to be fed directly from the meter via the Henley block - hopefully those are only lighting circuits?

 

[mattylad]

Turn no 2 off.
Take no1 out, take out no2 and try it in no1 position.
If it works without problem then the mcb from no1 is faulty and you need a new one, if the no2 breaker trips in the no1 position then you have a fault somewhere.

 

[terryplumb]

As mattylad advised above ,but turn off the main switch before swapping the MCB''s

 

[EFLImpudence]

If your shower is more than 7.5kW then it might have been overheating the 32A MCB and damaged it and 'worn it out'..

That does not mean you can just replace it with a higher rating without an electrician inspecting the situation.

 

[Calculus]

Thanks everyone. Davlex: the two-way one serve the lighting circuits only.

I've just thought of something. When this happened before the person who did the original rewire told me the MCBs came in different sensitivities and if the problem was not fixed by replacing the MCB like-for-like I could try one that was less sensitive, i.e. not so trigger happy. Any thoughts on this?

 

[terryplumb]

As I understand it ,the breaker on the circuit in question is a power / socket circuit ??

 

[Calculus]

If your shower is more than 7.5kW then it might have been overheating the 32A MCB and damaged it and 'worn it out'..

That does not mean you can just replace it with a higher rating without an electrician inspecting the situation.

It's a gravity shower, no electical connection

 

[Calculus]

As I understand it ,the breaker on the circuit in question is a power / socket circuit ??

It serves 12 power sockets in various parts of the house, upstairs and downstairs

 

[Calculus]

As I understand it ,the breaker on the circuit in question is a power / socket circuit ??

Further info:

 

[EFLImpudence]

It's a gravity shower, no electical connection

Ok, but you said it happened after the shower had been used.

 

[Calculus]

Ok, but you said it happened after the shower had been used.

It was the silicone sealant between the bath and the tiles. It looked OK superficially put gentle prodding revealed it was not properly adhering. The bath (shower) is directly above the kitchen and there is an electrical socket on the wall immediately below that side of the bathroom.

 

[terryplumb]

Don't follow your chart really ??? Columns marked 1,2,3,4 what relation do they have to the on/ off ?

 

[Calculus]

Don't follow your chart really ??? Columns marked 1,2,3,4 what relation do they have to the on/ off ?

I admit it's not a great chart . I made it a long time ago. The 1, 2, 3, 4 represent the MCBs left to right. 'on' means the socket is live when that MCB is switched on and the others are off.

 

[terryplumb]

Haha , I couldn't work out why all sockets were ON , under breaker 1, when that breaker will not set.
Did you try swapping the MCB'S ?