Old Cartridge fuses blowing, already tested and repaired before. What could it be?

[Joe S]

I have been to a call out today regarding an old cartridge fuse consumer unit. The customer said that the fuse went bang yesterday and she lost her Lounge, dining and one socket in the hallway (there is two but the other is on a different circuit). I went round and tested the circuit and found that there was a short between live and earth on one of the legs but when I tested between the lives there was no ring! I then took the plates off in the dining and lounge and found that the wiring has been altered between two sockets (stranded and solid). I replaced the 30a fuse with a 15a and put the good leg back in with the lives seperated at one of the sockets to find that all sockets worked bar the last two which she said she could live without as they are going to be redoing the whole house etc... so will be going for a rewire. Everything was working fine for over half an hour so we agreed it was fine with the TV, router, phones etc.. plugged back in. No high loads are on this circuit.

The earth loop was a touch high but its a TT system. There is a voltage trip between the meter and consumer unit
.
I have just had a call saying she has no TV again! I have isolated the problem leg with choc and tape so it cant make any contact.

What could it be??

Thanks in advance.

 

[telectrix]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

could be almost anything. even an overload on the 15A. you need to be there to suss this out. we're only able to guess.

 

[Joe S]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

Easier said than done mate. They're renting it with a view to buy and have only been there a month. She has literally only got a cordless phone, router, and all the TV, DVD, etc.. plugged into a 2x 4way leads downstairs. The rest of the house appears to be on the other 'good' circuit. Even on a radial with a 15a Cartridge fuse you wouldn't get tripping with that little lot.

There does appear to be quite a bit of a damp/ rust issue with the back boxes. There floors are all sanded and finished floor boards throughout although it is a suspended floor. I am thinking it could be a joint box problem below??

 

[stef]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

Nail through the cable underneath floor boards, erraticly short circuiting when walking over it:smilewinkgrin: not funny really, but it could be

 

[SirKit Breaker]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

If this is going to be long winded job, and they are going to rewire, then why not put a new CU and some new sockets in as temporary lash up, until they rewire.
Do a decent job of making it temporary though.

Cheers..........Howard

 

[Octopus]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

Has she got furry visitors with a taste for cable?

 

[Joe S]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

I may have to lift the nice floor boards to find out. I'm hoping the joint boxes are in that area and not the other side of the room!!

 

[ruston]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

What about timer or thermostat controlled appliances , Immersion water heater, or back boiler on a spur. Old poorly serviced Baxi's were notorious for this.

 

[Joe S]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

What about timer or thermostat controlled appliances , Immersion water heater, or back boiler on a spur. Old poorly serviced Baxi's were notorious for this.

I will look out for that mate, thanks. I think she may have a normal boiler though as the fireplace had a grate in iirc. Worth a double check though!

 

[Joe S]

Re: Old Cartridge fuses blowing, already tested and repaired before. What could it be

Sorted! Two bloody faults on two legs of the ring. Once I'd found and sorted the first fault, once energised and in use the other fault came up. Turned it into two radials and made it safe. Could have the rewire and extension coming way later in the year

Thanks for everyones input, much appreciated!