Electric Socket Went Bang - help on fixing please

DIYhelp76

Hello

Hope someone can help.

We plugged an extension lead into a socket and put the switch on the socket on.  Immediately it "popped/banged" and blew the circuit at the board.  Nothing was plugged into the extension lead at the time.

There is a black burn mark on the socket itself and on the extension lead plug.  Looking at the extension lead, the wire does seem to be loose/damaged and exposed, so we expect it was the extension lead that was damaged not the socket (it's one we've used countless times before and it must have become damaged and we didn't notice).

We would like help on how to know what further underlying cable damage might have been caused and to fix the sockets. The socket is on one wall in the kitchen. On the next wall along is a fused switch socket for our oven.  This socket also went off when the circuit blew. 

We switched the circuit back on at the board.  Now the oven fused socket is not working and we have no oven.  All other sockets in the kitchen are working fine but maybe they are on different circuits? (old house, old wiring).

We wonder if the circuit blowing could have just blown the fuse at this fused switch?  We assume, but don't know, if there is an actual fuse (like the ones you get in a plug) inside this fused socket and, if so, if we could try replacing this and then see if the oven socket works again?

For the damaged socket itself, the switch for this is "stuck" in the "on" position and won't let us switch it off.  We plan to switch off all mains electric and try changing this socket.  Our question is if we do this, how do we know whether the "popping" might have caused any more extensive damage to the wall cabling which seems to run from this socket to the oven socket?  

As mentioned, all other sockets in the kitchen are working, it is just these two.  It's an old house and I suppose old wiring.  

If we can safely try changing the socket ourselves and possibly the fuse in the fused switch socket, and further diagnosing from there then we'd like to start with this, rather than getting in an electrician right now.

In the meantime, is it safe to leave these sockets switched on at the main board especially when we are out of the house?  Difficulty with isolating them is that this would lose power to the fridge/freezer and spoil food.

We accept we may ultimately need an electrician if underlying circuit/cable damage has been caused but don't know how to diagnose if this is the case.

Apols for length of this post. Grateful for any advice on next steps.

Browntoa

The fuse is there to protect your wiring. I'd suspect that the fault is in the socket ( an easy job with the power off ) 

TELLIT01

No disrespect, but the questions you ask indicate that you have no understanding of the electrical circuits in your home.  That is true of many people.  I wouldn't mess with anything as a number of circuits seem to have tripped and won't come back on.  Get a qualified electrician in to check out and fix things.

Keep_pedalling

This will have been caused by a short circuit between the live and neutral, otherwise the RCD would have tripped before any serious damage occurred. It’s unlikely that any damage has been done to the ring/spur wiring, but for safety sake get a safety check done by an electrician. 

ThisIsWeird

Hi DIY76.
There is one socket which was damaged, and an oven switch which now has no power? Could we have a photo of the oven switch, please? Since the OS has a fuse plate on it, I presume it supplies a 'single' oven, the type that could even be 'plugged in'? Confirm please.
You will most likely be able to ID the cause of this incident by dismantling the ExtLead plug - have you done so? Most likely it's as you say - the shorted wires were inside this plug, but why the plug's fuse didn't blow is interesting and worth trying to figure out. I'm struggling to think of a 'shorting' action that doesn't have the plug's fuse in the circuit, so I'd really want to know why that fuse didn't blow - it should be 13A max, so way less than the MCB - tho' probably 'slower'.
I'd just cut the EL cable a few inches from this plug, investigate the insides, and wire on a new one.
It doesn't make obvious sense that the oven - on a different wall - is now not powered. Potentially of some concern, as the only answer I can come up with is that it's on a spur from the damaged socket - IE fed by a single cable in the wall. Surely not ideal.
If this had been a simple case - faulty or shorted plug which damaged just that one socket, I'd be the first to suggest - provided you are 'capable of wiring a plug' ( the basic level!) - simply replacing the socket, and we could guide you if necessary. But there is clearly something more going on, and it isn't obvious (to me, at least) what that is, so can only recommend to get a sparky.
It might be simple - a loose terminal in that socket where it spurs to the oven - but that would be a strange coincidence of two faults present at the same time. It's just a bit weird. 

CSI_Yorkshire

ThisIsWeird said:

I'm struggling to think of a 'shorting' action that doesn't have the plug's fuse in the circuit, so I'd really want to know why that fuse didn't blow - it should be 13A max, so way less than the MCB - tho' probably 'slower'.

16A MCBs frequently operate faster than 13A fuses.  I find many situations where a circuit has tripped at the MCB but the fault lay in an appliance whose plug fuse was still continuous.

Section62

ThisIsWeird said:

I'm struggling to think of a 'shorting' action that doesn't have the plug's fuse in the circuit, so I'd really want to know why that fuse didn't blow - it should be 13A max, so way less than the MCB - tho' probably 'slower'.

A BS1362 '13A' fuse can pass far more current than 13A - the key is in the "slower".  It should pass 20A indefinitely, and (say) 100A for up to 0.3 seconds.

In other words more than enough current to allow other devices to trip first, or potentially to weld switch contacts to each other... a possible cause of the switch no longer working.

For that reason, and that this is an "old house, old wiring" I agree with TELLIT01.  It would be wise to get a professional electrician in to check the wiring and replace the socket (and anything else) which has been damaged.  There is the possibility of other faults (not just the extension lead damage) which contributed to this situation.

FreeBear

Section62 said: For that reason, and that this is an "old house, old wiring" I agree with TELLIT01.  It would be wise to get a professional electrician in to check the wiring and replace the socket (and anything else) which has been damaged.  There is the possibility of other faults (not just the extension lead damage) which contributed to this situation.

Old wiring - A good chance some bodger has "extended" stuff and used the incorrect size cable. If the oven is on a cooker switch, that would usually a 32A or even a 45A circuit direct from the consumer unit. Running a spur from a cooker switch is questionable....

As for the extension lead - Just bin the darned thing (dispose of it responsibly by taking it to your local recycling centre). It is not worth cutting the plug off & replacing it. The fault could be at the other end.

Risteard

Keep_pedalling said:

This will have been caused by a short circuit between the live and neutral, otherwise the RCD would have tripped before any serious damage occurred. It’s unlikely that any damage has been done to the ring/spur wiring, but for safety sake get a safety check done by an electrician. 

Who said that there is an RCD? Also a phase/Earth fault can rupture a fuse - not just a short circuit.

FFHillbilly

TELLIT01 said:

No disrespect, but the questions you ask indicate that you have no understanding of the electrical circuits in your home.  That is true of many people.  I wouldn't mess with anything as a number of circuits seem to have tripped and won't come back on.  Get a qualified electrician in to check out and fix things.

you've hit the nail on the head. whenever people use terms like "it blew at the circuit board" you realise they don't fully understand
to explain, instead of the above what you should be saying is "the 63A RCD feeding the affected circuit or the 32A MCB feeding the sockets tripped" this helps people advise further

flashg67

(FYI, I'm not an electrician but have some experience with wiring)As you suggest, try changing the fuse in the cooker outlet - it should have a small retaining screw or a small slot to insert a screwdriver to prise out the fuse holder, Changing a socket isn't difficult if you take your time. Always switch off at the main board before starting any work