Lighting circuit error

[ban-all-sheds]

TBH, given the way this has unfolded so far, it indicates the need for you to get an electrician.

 

[DOTElectrical]

i wouldn't jump to the conclusion that there is something wrong with the rest of the circuit if you havn't changed anything else. please post a picture of the connections at the choc box.

sounds more like youve mixed up a live and a neutral somewhere.

A picture of the switch connections for the switch that controls the light fitting may also prove useful.

 

[Mattbaigent]

Am taking pictures now. Have contacted an electrician but hasn't got back to me yet! Glad it's a really warm day, perfect for loft work...... Not

 

[Mattbaigent]

Also, I'm using the continuity setting and touching the live and the earth, on one I get a circuit but not the other? Switch wire is definitely the switch wire.

Thanks for all of your help so far, I'd be totally lost right now.

 

[DOTElectrical]

I take it you have linked the live and earth at the switch or somewhere to get the continuity reading?

 

[Mattbaigent]

I have only done it on the switch wire. The other one I haven't, would that mean they are touching somewhere and that'd be whys it's blowing?

 

[DOTElectrical]

if you are just putting your test leads on a live and the earth, without have joined live and earth together somewhere, then that would indicate that they are touching somewhere. Any continuity between a live and an earth with cause the fuse to blow/trip when turned on.

 

[Mattbaigent]

Ok great, I'll go hunting for damaged wires. Is there any common place where this would happen or is it most likely damage to the wire?

 

[DOTElectrical]

well i would stop and think about where you have changed anything. if you have just altered that ceiling rose, turning it into a choc-box, and also you have repositioned a cable at the switch, this correct?

if so i would start by unscrewing the switch from the wall removing the screws, then test continuity again, could have nicked a live cable with a screw holding switch on the wall.

if not there then have you put any other screws in?

 

[Mattbaigent]

Yes, that is correct! The wires when leading into old ceiling rose were secured into the joists with the nail in wire clip and they all had a really tight bend in them. Could the cable housing tear inside?

 

[DOTElectrical]

It is possible, not very common though, how old is existing wiring?

Did you try unscrewing your switch from wall and re-checking continuity?

Might be worth waiting for electrician...where in the UK are you?

 

[Mattbaigent]

Yea. The switch side was fine. I tracked back the wire that was faulty and it lead down into a bathroom shaving socket and the live wire was lose. It doesn't lead to anywhere else so I guess it's the last in the circuit!

 

[Taylortwocities]

Loose wires do not cause fuses/mcbs to "blow".
Loose wires cause less current to flow, not more.

You have created a fault with whatever you have been doing. Look there first, not anywhere else.

 

[Mattbaigent]

But after securing it I'm not getting anything from the wire with the continuity test!

 

[riveralt]

The reason for my confusion yesterday was because you keep introducing new elements into the story.
Yesterday, I think you started talking about a two way circuit, with a yellow wire mentioned at the switch.
Today you have added the bathroom shaving socket to the plot.
Hence we are all having difficulty understanding what type of circuit you are actually working on.
So is this a TWO WAY circuit or not?
If not then my guess is that in originally extending the wiring four feet you have crossed the switch live with a neutral - marrying up the same colours - that is why
your circuit keeps blowing.
I think TTC mentioned this yesterday but I will repeat it again, if you haven't already done so you need to remove the extension, and test for continuity on the circuits
live/switch live back at the original ceiling rose - once done your other two cables are your permanent live and neutral.
If you don't understand how to test then the only other option is to go back into the loft and physically trace the T&E that goes from the ceiling rose to the switch.
Assuming it is not a two way circuit then back at the ceiling rose your two remaining cables are the permanent live and neutral