No power through ceiling rose

[smartin1612]

Hello all,

I'm replacing a 3-bulb spotlight with a standard BG ceiling rose but upon connecting, the light won't turn on; the problem is, I can't see why.
We can handle the wiring shortly, but after a day or two of testing - wiring the spot back on, test (it works), replacing with the ceiling rose (it doesn't work), I finally gave up and wired the spotlight to a plug and tested - dropping the 13A down to a 3A first.
The spotlight predictably worked as expected, but upon switching over to the ceiling rose, using the same bulb as the spotlight - it's a 7w bulb, I'm not getting anything, although I am registring power both on the cable terminals and, the light terminals, just no light. It's as though the light terminals are performing a huge resistence that the power could not overcome it and light the lamp.

I have already gone through the motions of junction boxes and switches trying to troubleshoot, which came-up blank - even to wiring the rose direct to the light cicuit and the junction box in the attic [we're still on junction boxes for the lighting circuits rather than using the rose loop] to bypass the switch [using the RCD as a switch], and predictably, I got nothing, hence the direct to wall-outlet approach as a last resort.

Any ideas?

 

[Midwest]

What about a pic of the wiring at the the ceiling where the luminaire was originally. Or have I got hold of the wrong end of the stick?

 

[smartin1612]

What about a pic of the wiring at the the ceiling where the luminaire was originally. Or have I got hold of the wrong end of the stick?

Slightly wrong end of the stick at present as after spending the last couple of days troubleshooting, I've determined the problem to be with the lampholder and not the wires at the ceiling.

If the light works when plugged into the wall, nut not the ceiling, then we know its something else, but currently, as its not working from the wall outlet either, when the original 3-lamp spotlight is, tells me the problem is with the lampholder.

 

[smartin1612]

The connections really need tidied up. im not sure if some of those flexes are held in the screws properly, and so much copper showing, they could touch together

I don't care for the connections right now, you are seeing a test cable connected to a wall-plug rather than off the ceiling, as right now, I'm troubleshooting the lamp-holder.
Once I go back to the ceiling, they'll be covered in heat-shrink

 

[smartin1612]

Are the terminals lining up with the terminals on the bulb.

I believe so, I pulled the terminals up and in a little to ensure the connection is made

 

[westward10]

So just to clarify the new lampholder does not function at the rose nor the wall outlet but you know the spotlight is good because you have proved this at the old spotlight track.

 

[smartin1612]

Found it - short circuit!

7 frickin days I've lost to this, with the two main rooms upstairs in darkness, not great for home workers, the amount of meetings I've held looking like something on Halloween...

I made mention of my Asrock pc build back in 2005 - it was terminals:

My Asrock motherboard had a bit too much solder on the back of the circuit board.
It worked outside the case, but the moment I installed it, nothing. No power, no resistance, nothing. No CMOS, no BIOS.
Take the motherboard out, and the pc would fire-up.
Took me two days to resolve, and was only as I was about to send back did I discover it: the screw in the middle of the motherboard was pushing the board down just too much, it was contacting the case and shorting.



Double-checked the terminals of the lampholder and sure enough pushing the netural away a bit, the lamp fired up.


Netural was too close to live and was shorting, though not killing the rcd - gotta look into that.

 

[smartin1612]

So just to clarify the new lampholder does not function at the rose nor the wall outlet but you know the spotlight is good because you have proved this at the old spotlight track.

Yes, that's correct

 

[westward10]

Can you show this apparent short.

 

[smartin1612]

Can you show this apparent short.

How do I show the short?

As explained, pushing the neutral terminal further away from the bulb allowed the bulb to fire - obviously I had to make the mod with the bulb out and keep testing until I'd found the sweet spot - too far away annd the neutral wouldn't connect too close, and whilst the bulb would contact, it wouldn't power on.

 

[DPG]

I can't picture where this short was.

Presumably the fuse blew or MCB tripped?

 

[mainline]

I can't picture where this short was.

Presumably the fuse blew or MCB tripped?

I think there is a little confusion between what is a short and what's an open.
I think the OP should put a multi meter on his Christmas wish list

 

[smartin1612]

I can't picture where this short was.

Presumably the fuse blew or MCB tripped?

The light came on only after I moved the neutral terminal away from the side of the bulb. It has just occurred to me that I didn't explain the lamp fixing type - these are screw bulbs.

So as the neutral would've been in contact with the side of the bulb regardless, I can only assume that neutral was contacting live, although the rcd wasn't tripping out so still trying to work that one out

 

[smartin1612]

I think there is a little confusion between what is a short and what's an open.
I think the OP should put a multi meter on his Christmas wish list

Rude.
And what makes you think I don't have a multi meter?

 

[mainline]

The light came on only after I moved the neutral terminal away from the side of the bulb. It has just occurred to me that I didn't explain the lamp fixing type - these are screw bulbs.

So as the neutral would've been in contact with the side of the bulb regardless, I can only assume that neutral was contacting live, although the rcd wasn't tripping out so still trying to work that one out

If the neutral was contacting Live it would be the mcb that went.

 

[mainline]

Rude.
And what makes you think I don't have a multi meter?

Because you're working with Mains electric and wiring plugs etc when you could have used your multimeter instead.