main fuse tripped

Joined
10 Dec 2009
Messages
689
Reaction score
15
Location
Middlesex
Country
United Kingdom
Bought three flush mounted sockets to replace the stock white plastic ones in a room that im decorating.

Fitted them a couple of weeks ago and all working fine. No issues.

Last night was decorating and loosened the fixing screws just so the sockets could be displaced and allow me to paint around thw socket.
On moving one of the sockets probably no more than 10mm a loud pop and lots of sparks came from behind the socket.
The circuit the sockets was on tripped and also the main entry fuse in the meter box tripped.

On inspection the socket live terminal is quite charred. All wires however were firmly clamped in place.
There are no scorch marks on any of the wires
I hadn't started painting and all tools were clear of the socket.

Other that a faulty socket which I doubt as it was working fine for a couple of weeks what else could have caused this?
 
Sponsored Links
Joined
11 Jan 2004
Messages
39,758
Reaction score
2,019
Country
United Kingdom
There must have been a short circuit.

Did you put your screwdriver behind the socket?

Is there a charring on the earth bar anywhere?
 
Joined
2 Jun 2005
Messages
14,841
Reaction score
477
Location
Cumbria
Country
United Kingdom
Moral of the story, isolate before working on any electrical circuit.
 
Joined
10 Dec 2009
Messages
689
Reaction score
15
Location
Middlesex
Country
United Kingdom
Definitely no tools or screw drivers any where near the socket or back box.

There shuldnt be any but
I will double check for any exposed wires tonight.

Lesson learnt though... will take the time to isolate in future even if its just for a 'quick' job
 
Sponsored Links
Joined
2 Jun 2005
Messages
14,841
Reaction score
477
Location
Cumbria
Country
United Kingdom
If it was a metal back box it may be just the live screw has come into contact with it.
 
Joined
27 Aug 2003
Messages
69,778
Reaction score
2,884
Location
London
Country
United Kingdom
the main entry fuse in the meter box tripped
I find that hard to believe.

  1. Fuses don't trip, they rupture, or "blow".
  2. The main fuse can only be replaced by the DNO - did they attend today?
  3. The protective device in your for that circuit really should have operated before the service fuse went.
 
Joined
25 Mar 2011
Messages
2,476
Reaction score
327
Location
Devon
Country
United Kingdom
Or an ELCB (old voltage flavour)
Ooh I removed a 3 phase version of one of those last week.

Have you replaced the socket with a new one yet?

Sometimes old cutout fuses can blow when there is a fault. I went to a call out where a very old electric heater had gone bang when it was switched on, and blew the cutout fuse. I still have the old heater it works fine and I could find no signs of any faults, either current or previous...
 
Joined
2 Nov 2008
Messages
168
Reaction score
4
Location
Lancashire
Country
United Kingdom
My wife switched a light on and it tripped the MCB and on investigation I found a single screw for the back box at an angle with a sharp edge this had penetrated the insulation on the live wire so had to countersink the hole in the back box so it fits nearly flush fortunately there was enough wire to cut the bad bit out.

Andy
 
Joined
8 Sep 2011
Messages
4,637
Reaction score
590
Location
Warwickshire
Country
United Kingdom
My wife switched a light on and it tripped the MCB and on investigation I found a single screw for the back box at an angle with a sharp edge this had penetrated the insulation on the live wire so had to countersink the hole in the back box so it fits nearly flush fortunately there was enough wire to cut the bad bit out.

Andy
Using pan head screws avoids this problem. Can't say I've ever needed to countersink a knockout box to get the screw flat enough. Even with a countersunk screw head.
 
Joined
2 Nov 2008
Messages
168
Reaction score
4
Location
Lancashire
Country
United Kingdom
My wife switched a light on and it tripped the MCB and on investigation I found a single screw for the back box at an angle with a sharp edge this had penetrated the insulation on the live wire so had to countersink the hole in the back box so it fits nearly flush fortunately there was enough wire to cut the bad bit out.

Andy
Using pan head screws avoids this problem. Can't say I've ever needed to countersink a knockout box to get the screw flat enough. Even with a countersunk screw head.
I had to use what I had to hand but all the switches are the same so I will get some of those screws.

Andy
 
Joined
8 Sep 2011
Messages
4,637
Reaction score
590
Location
Warwickshire
Country
United Kingdom
Did you do them up by hand? if you use a drill/impact driver you can just force them in so far the box bends and you don't need to bother :rolleyes:

(that's half serious - if you do them up tight enough it's not an issue, just don't over tighten them)
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Top