12v lighting

[northpaw]

chaps.
I have some 12v halogens in the kitchen. they continually go off. if i take the bulbs out and put them back in again, they work, for a time before going off again. sometimes they work when they are out of the mountings, and as soon as they i put them back into the mountings, they go out. as if they are taunting me! dont think its a broken wire. what else could it be?

also, i just insulated the loft, and the halogens in the bathroom below have just burn their cables through. how can i stop this happening again?

cheers

 

[Spark123]

Could be dodgy lamp holders which when they get warm open up disconnecting the lamp from the supply, could be transformers overheating and shutting down.
Don't cover the lamp fittings/transformers with insulation.

 

[philrosenberg]

Not sure about your kitchen but as far as the bathroom is concerned the halogens should have an unobstructed area to allow heat flow around them. I think in the instructions for the last set I bought it said 110mm but I'm not sure offhand. Also laying insulation on cable derates them (by up to 50%), because the heat generated in the cables themselves cannot escape and can causes the pvc to melt wheras exposed this would not be the case. If you have just laid insulation over the top of all the wiring in your loft then you may well have created other areas where you are likely to melt cables.

This could obviously be a very dangerous situation and needs sorting immediately if it is what you have done.

 

[breezer]

i bet its the lamp holders, slightly (and i mean slightly) bend the lamp prongs apart

 

[miajanjua]

i bet its the lamp holders, slightly (and i mean slightly) bend the lamp prongs apart

I second the geezer

 

[securespark]

Often I find small heat damage to one or both cores of the lampholder.

 

[RF Lighting]

Keep all cables joint boxes trannies etc well away from the light, and remove all insulation from over the downlights oterwise your cable will be toast.

Kinda like this:

 

[northpaw]

thanks for the posts chaps.

all the other cables/trannies in the loft are exposed on top of the insulation,
silly of me really to cover the lights with insulation. should have known better.
will try the bending the bulb thing trick tonight.

 

[securespark]

Cables & tx's should be kept away from insulation altogether wherever possible.

 

[DESL]

I'd consider fitting these as there is less radiant heat generated around the back of the fitting

http://www.tlc-direct.co.uk/Main_In...hts_Index/Fire_Rated_Downlights_Lv/index.html

They are essential if there is an occupied rome above

Some transformers have a thermal cut out

 

[Steve]

They are essential if there is an occupied rome above

no they are not!