What have i done???

[Edward2k9]

Hi Guys and Gals,

Im in a bit of a dilemma, i am currently decorating my daughters room, tonight, i moved the ceiling light one foot so it was central to the bedroom instead of near the window.

I reconnected it all back up and now i blow a fuse. If i connect the wires up then switch the whole house off and plug the fuse in, then switch the mains back on the light works untill i turn the light off and it blows the fuse.

I have three cables coming out of my light socket, 3 x black, 3 x red and 3 x earth which are not connected to anything and never were when i took it out to move it.

i have the three reds together into a chocolate box the same for the black wires, in another chocolate block, this is how it come out of the ceiling.

Now the puzzling bit is when i connect the three wires together with the fuse out, i get an electric current through one of the earths! as it tingles my finger, so i thought i must have a break in the cable, so i got my power detector thing and think i found the problem, cut above where i thought the break was, but alas same problem.

So what i have now, is two bedrooms with light, one bedroom with out and the bathroom and landing with out light?

Electrics isnt my strong point, but i thought moving a light socket a foot would be pretty simple.

Can anyone help with what ive done wrong?

Thanks for your time

Edward

 

[RF Lighting]

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

 

[RF Lighting]

And stop touching wires with your fingers with the power on.

All it takes is a simple fault, and doing what you have done will KILL you.

I am not kidding. What you have does is rediculously unsafe.

 

[holmslaw]

..

 

[DCC]

To be fair he did say "with the fuse out".

(he also said it was an earth that was tingling... whats all that about anyway?)

 

[flameport]

Fuse out or not, you NEVER poke at wires with your fingers until you have proved the wires are dead.

The earth issue suggests that particular wire is not connected to earth, and there is another fault, (probably N-E) elsewhere in the circuit.

 

[DCC]

Agreed that you dont poke stuff but like me the OP is obviously an amatuer and we don't know all the good stuff! My test for dead used to be switch it on, pull the fuse, light goes out - fine start poking around. On learning a bit more I read about things like borrowed neutrals and stuff that might cause problems even if I've pulled the fuse and I guess that with my meter I could poke around a bit and have a go at checking for it but.... what would you do to check the earth is (going to be) safe after you isolate?

 

[ban-all-sheds]

3 x earth which are not connected to anything and never were when i took it out to move it.

Does the light have an earth terminal?

i have the three reds together into a chocolate box the same for the black wires, in another chocolate block, this is how it come out of the ceiling.

No it isn't.

And since you didn't have the fuse blowing all the time before it must surely be obvious that it can't have been wired like that before.

The Wiki article will show you how it should be connected up.

You might find you need a new switch as well.

 

[thomo27]

I have three cables coming out of my light socket, 3 x black, 3 x red and 3 x earth which are not connected to anything and never were when i took it out to move it.

That is incorrect.

One of your blacks is the switch wire - the cable that runs from the switch to the light. If you cna't understand thiis simple problem you need an electrician.

To identify which black is your switch wire you will need a multimeter , turn the switch to the on position and put 1 probe onto an earth and the other onto each black and the switch wire will be identified by seeing a reading of 240V you then need to add some red sleeving or tape to this wire to mark this as your switched live. This test is done with the power on so do not touch the cables. Once complete then the switched live goes to Live on the lamp and the remaining blacks are your neutrals

 

[ban-all-sheds]

Not the safest way to ID the switch cable - better to test for continuity between red & black with power off and the switch on .

 

[Goldberg]

when i connect the three wires together with the fuse out, i get an electric current through one of the earths! as it tingles my finger

Are you in love, or just friends?

 

[ColJack]

thomo that won't work to id the switch wire.. it's possible to "see" 240V through the neutral that is disconnected as it will feed through the next light on the circuit back up the neutral..

so you would get 2 black wires showing at 240V..

the safest way is to do it with the power off and use the continuity or low ohms setting....

 

[thomo27]

thomo that won't work to id the switch wire.. it's possible to "see" 240V through the neutral that is disconnected as it will feed through the next light on the circuit back up the neutral..

so you would get 2 black wires showing at 240V..

the safest way is to do it with the power off and use the continuity or low ohms setting....

ok cheers Coljack youve confused me now lol

in my garage I have 3 baton lamp holders controlled from 1 switch , at the first baton lamp holder I have 2 blues , 1 switched live and 3 browns 1 of which is the switched live to the baton holder number 2 , I only get 240 V on the switched live not on the other 2 neutrals

 

[thomo27]

i'm struggling to see why you would get 240 on a neutral when they are disconnected

Appreciate any help cheers

 

[ColJack]

View media item 14367switches omitted for clarity..

with a switch on somewhere downstream of the break in the neutral ( or in your example where lamps are in parallel ) , the voltage present on the live goes through the lamp as there is no path for current to flow..
a normal filament lamp is a low resistance so looks like another piece of wire to a multimeter..

so the meter "sees" the live through the lamp..

of course in your example, you would also have the switch wire disconnected.. but for normal use in a house, any switch on downstream would give a 240V on the neutral that is not connected to the board..