Electrical Puzzle

[rhinochopig]

I've been trying to fit a new light into our 1930s house - electrics are a little odd. Anyway I just cannot seem to get the bloody thing to work. It's either on all the time, or on when the switch is off and then trips the fuse board when turned on.

The light is some poncy metal thing that my wife bought and doesn't have a ceiling rose so it's a case of using connector blocks.

Can someone tell me which cables connect to which. NB Cable B is the one that goes to the switch. Also it there is only one light switch in the bedroom - I don't know why one is a three core and earth. ETA The two cables at the top are what is poking out of the ceiling.



Please help, it's driving me bloody mad, and I keep getting a bking for swearing very very loudly.

Edited by rhinochopig on Monday 23 November 09:38

[Ganglandboss]

The only thing you can do is get a spark in. Something is not right by the looks of that and without being able to see it, I could only guess.

[rhinochopig]

Ganglandboss said:

The only thing you can do is get a spark in. Something is not right by the looks of that and without being able to see it, I could only guess.

The thing is the there was a light there before (in a rose) which all worked fine - stupidly I didn't note what was connected to what as I thought it would be straight forward. It "Should" be possible to get this to work - no????

[Deva Link]

Assuming (this is a BIG assumption) 1 & 2 are the live and neutral supply it's difficult to imagine what yellow wire 3 would be doing. If it was the live loop to the next ceiling rose, then there should also be a neutral loop.

Lighting circuits can be very messy - have you got separate upstairs and downstairs lighting circuits? They can even then get messed up as the stair/landing lights cover both floors.

With the current fitting disconnected, is every other light in the house working OK?

This is how a modern ceiling rose should be wired:

[sunbeam_alpine]

I'd be CAREFULLY using a tester to see which cables in Cable A are live, in both switch positions.

[Deva Link]

sunbeam_alpine said:

I'd be CAREFULLY using a tester to see which cables in Cable A are live, in both switch positions.

The switch is disconnected so that won't really help. You also can't easily tell which (if any) is the looped onward live as it's not live until it's connected to something!

[rhinochopig]

Deva Link said:

Assuming (this is a BIG assumption) 1 & 2 are the live and neutral supply it's difficult to imagine what yellow wire 3 would be doing. If it was the live loop to the next ceiling rose, then there should also be a neutral loop.

Lighting circuits can be very messy - have you got separate upstairs and downstairs lighting circuits? They can even then get messed up as the stair/landing lights cover both floors.

With the current fitting disconnected, is every other light in the house working OK?

This is how a modern ceiling rose should be wired:

When I disconnect the wires totally all lights are off. TBH I'm not sure the yellow actually does anything - it may be a case of they had some three and earth left and just used it as two and earth.

[Deva Link]

rhinochopig said:

When I disconnect the wires totally all lights are off. TBH I'm not sure the yellow actually does anything - it may be a case of they had some three and earth left and just used it as two and earth.

So how are they connected when the lights are working?

I would say there's absolutely no chance they used the 3 core + E cable if they didn't have to.

[rhinochopig]

Looks like Electrician time. Cheers anyway chaps.

[Mikey G]

Isnt the yellow normally used as the link in a 2 way landing light switch setup?

[WorAl]

hope this helps

http://www.make-my-own-house.com/diagram-electrica...

ETA: as far as i remember there are 2 wires to be wired to the live in the light. 1 neutral, 1 earth (bare).

Edited by WorAl on Monday 23 November 10:28

[rhinochopig]

Deva Link said:

rhinochopig said:

When I disconnect the wires totally all lights are off. TBH I'm not sure the yellow actually does anything - it may be a case of they had some three and earth left and just used it as two and earth.

So how are they connected when the lights are working?

I would say there's absolutely no chance they used the 3 core + E cable if they didn't have to.

That's the problem, the previous light was a pendant on a proper ceiling rose. I stupidly didn't note down which wires were connected to which terminals - I'd foolishly assumed it would be dead straight forward to reconnect.

The new light sits on a hooked plate so a rose cannot be used. You have to use connector blocks.

[rhinochopig]

Mikey G said:

Isnt the yellow normally used as the link in a 2 way landing light switch setup?

Yes, but there is only one light in the room. I'm told - wife's uncle is a sparky but live 100 miles away and wasn't able to help over the phone - that a lot of older houses had a two way set-up to enable a pull cord fitting over the bed. This is no longer there.

[Deva Link]

Mikey G said:

Isnt the yellow normally used as the link in a 2 way landing light switch setup?

Yes, but it goes from switch to switch you wouldn't normally expect to see it at the ceiling rose.

You just don't know what's going on though. I was in a bungalow the other day and pulled the (single, 5A) lighting fuse out and the TV went off!

[WorAl]

its old school wiring, it makes no sense at all.

[Road2Ruin]

I would hazard a gues to say that they didnt have the proper coloured cables so did a job with what they had.

My guess is:

1,3,x go together in same block (loop in/out), I reckon 3 is the loop to the next light.

Y & d together for power to light though switch.

2 & c together neutral

4, z & either a or b. (this one seems odd as you have too many cables at the light end) However it could be that it has more than one earth for some reason due to the lamps properties!

Good luck.
Peter

[rhinochopig]

Road2Ruin said:

I would hazard a gues to say that they didnt have the proper coloured cables so did a job with what they had.

My guess is:

1,3,x go together in same block (loop in/out), I reckon 3 is the loop to the next light.

Y & d together for power to light though switch.

2 & c together neutral

4, z & either a or b. (this one seems odd as you have too many cables at the light end) However it could be that it has more than one earth for some reason due to the lamps properties!

Good luck.
Peter

Cheers will give it a try. The two earths at the lamp end are cable earth and casing earth - light is metal.

[rhinochopig]

Road2Ruin said:

I would hazard a gues to say that they didnt have the proper coloured cables so did a job with what they had.

My guess is:

1,3,x go together in same block (loop in/out), I reckon 3 is the loop to the next light.

Y & d together for power to light though switch.

2 & c together neutral

4, z & either a or b. (this one seems odd as you have too many cables at the light end) However it could be that it has more than one earth for some reason due to the lamps properties!

Good luck.
Peter

Genius - we have a winner. Many many thanks Sir! Why live to neutral though - Y + D?

[Deva Link]

rhinochopig said:

Road2Ruin said:

I would hazard a gues to say that they didnt have the proper coloured cables so did a job with what they had.

My guess is:

1,3,x go together in same block (loop in/out), I reckon 3 is the loop to the next light.

Y & d together for power to light though switch.

2 & c together neutral

4, z & either a or b. (this one seems odd as you have too many cables at the light end) However it could be that it has more than one earth for some reason due to the lamps properties!

Good luck.
Peter

Genius - we have a winner. Many many thanks Sir! Why live to neutral though - Y + D?

It's not neutral. It's a piece of wire that is (in this case) incorrectly coloured black. It's a switched live and you should put red tape on it to indicate that.

[rhinochopig]

Deva Link said:

rhinochopig said:

Road2Ruin said:

I would hazard a gues to say that they didnt have the proper coloured cables so did a job with what they had.

My guess is:

1,3,x go together in same block (loop in/out), I reckon 3 is the loop to the next light.

Y & d together for power to light though switch.

2 & c together neutral

4, z & either a or b. (this one seems odd as you have too many cables at the light end) However it could be that it has more than one earth for some reason due to the lamps properties!

Good luck.
Peter

Genius - we have a winner. Many many thanks Sir! Why live to neutral though - Y + D?

It's not neutral. It's a piece of wire that is (in this case) incorrectly coloured black. It's a switched live and you should put red tape on it to indicate that.

That at least makes me feel better. Once again the power of PH to the rescue.