Fuse blowing

[delboy24]

Can anyone help the lounge light keeps blowing the fuse.
All the other lights work in the house confusing it is.
Its a 1 gang switch. On the main board i have disconected the live wire for the lounge light so all the others are working, if i put it back in the light fuse it just blows any ideas anybody... I am thinking maybe a loose wire under floorboards..

 

[Spark123]

A loose wire doesn't cause a fuse to blow unless it is touching something else, either a live-earth or live-neutral fault is more likely. Any work been done recently?

 

[PrenticeBoyofDerry]

Have you changed the switch or fitting?
As above any recent work done in the property, that may have affected the lighting circuit?
Do you have rodents?
Always worth checking for loose connection, it could be shorting.

 

[ericmark]

I will guess you have changed the lamp and in doing so have connected the switched live should be sleeved but often sleeve is missing so is black to the neutrals.

Often the lights seem to work but when you switch off the fuse blows.
Really the lights are live at all times and when you switch on you are producing a direct short.

So have I guessed correct?

 

[delboy24]

hi i havent used the light for a good few years i had alarm fitted to it but it kept going off when the fuse blew.
so i disconnected it from the rose under the floor board.
Now i have just got a fitting put it up put the live wire back in the fuse all lit up but 10 mins later its blown again.
the live wire which i am on about is the one behind where the fuse is. if that helps. Now i have took it out again so the other lights will work.
Everything used to work ok but it just gradually started to blow and got more frequent.

 

[PrenticeBoyofDerry]

hi i havent used the light for a good few years i had alarm fitted to it but it kept going off when the fuse blew.
so i disconnected it from the rose under the floor board.
Now i have just got a fitting put it up put the live wire back in the fuse all lit up but 10 mins later its blown again.
the live wire which i am on about is the one behind where the fuse is. if that helps. Now i have took it out again so the other lights will work.
Everything used to work ok but it just gradually started to blow and got more frequent.

Confusing!
Live wire behind fuse, disconnected when alarm fitted, kept blowing?
I think we need a little detail/info here.

When was the alarm fitted?
When was the light disconnected?
When did the fuse start to blow?
Is this recent activity or historical work?
Is this light part of the rest of the light circuit?
What type of fuse do you have?
Have you ever tested for insulation resistance?
Photos may help!

 

[ban-all-sheds]

hi i havent used the light for a good few years i had alarm fitted to it but it kept going off when the fuse blew.
so i disconnected it from the rose under the floor board.
Now i have just got a fitting put it up put the live wire back in the fuse all lit up but 10 mins later its blown again.
the live wire which i am on about is the one behind where the fuse is. if that helps. Now i have took it out again so the other lights will work.
Everything used to work ok but it just gradually started to blow and got more frequent.

Before you do anything else you should read this.

//www.diynot.com/wiki/electrics:lighting

 

[delboy24]

i had an alarm fitted years ago but 2 to 3 years after the fuse started blowing in the fuse box 5amp wire so everytime i put a new fuse wire in 10 mins later it would pop and the alarm would go of, getting fed up of it i disconnected the alarm and a red live wire behind the fuse box. Hey presto all the the lights worked apart from the lounge, we never used it so we left it be. However i bought a new fitting and decided to fit it old wiring i came on here and found the answer i was looking for to wire it up, on doing so i remembered taking the live out of the fuse box and encasing it. So i put it back and hey presto lights worked great then 10 - 20 mins later it has popped the fuse again. so i have had to take the live red out and isolate it again as if i leave it in it pops and i have no lights.
When you pull the fuse out theres a screw which i undo and 2 red live wires screwed into it i remove one of them which is the lounge light and the other must power all the other lights in the house. ????

 

[mfarrow]

Check behind the switch for any loose wires, particularly earths touching lives etc.

Is the alarm on the same circuit as the lights?

 

[PrenticeBoyofDerry]

So apologies for my ignorance!
You disconnected a live form the circuit of the light in the lounge to isolate a fault.
Then left it for 2 maybe 3 years, thinking it would repair it's self?
It's oblivious you have a fault on the circuit, dare I assume that the fault appeared on the circuit soon after the alarms was installed?
If so who installed the alarm, you should have got them back?
Assuming the cables have been terminated correctly in the first/second place.
The correct way to identify this faulty is by firstly identifying the circuits conductors and making sure they are not connected elsewhere, disconnect all loads, doing a little investigation at all accessories (switch plate, junction box, light fitting) for loose, burnt, damages to conductors or insulation.
Then go through the tests for continuity and insulation resistance.
How old is the wiring on this particular circuit as it sounds like you have a insulation resistance problem, that is why it does not blow straight away.
http://www.tlc-direct.co.uk/Book/8.1.1.htm

 

[Johnmelad]

So apologies for my ignorance!
You disconnected a live form the circuit of the light in the lounge to isolate a fault.
Then left it for 2 maybe 3 years, thinking it would repair it's self?

Sarky... You a little BAS?

 

[PrenticeBoyofDerry]

Sarky... You a little BAS?

Sometimes you need to use BAS-tactics. The logical approach would have had to have been, to apply a little common!

 

[kai]

It sounds like the alarm installer made a mess of your circuit!
You should called him back at the time to sort it out!