12V lighting - which wires to use ?

[Supra-Brett]

OK im having some 12V lights installed in the house. Ive bought 6x 12V fire rated downlights and 6x suitably sized transformers to power them. I can aim to create a loop of 6x junction boxes to loop the main feed using 1.5mm twin and earth, and from each junc box i will power a transformer. Here the bit im stuck on (not really stuck, just want to get it right).

 

The tranformer will be no closer than 20cm to the 12V light (thats the advice on the box) and no further away than 50cm.

 

There are only 2 wires coming from the transformer to the 12V light and 2 connectors to recieve them on the 12V light(makes sense as they are double insulated so no need for an earth.

 

Can i use 1.5mm twin and earth to link the transformer to the 12V light ?

 

Should i use normal car audio cable ffrom the transformer to teh 12V light ? if so what gauge ?

 

Any advice welcome

[Kev.O]

Twin and Earth or flex is the most suitable cable

[Supra-Brett]

Twin and Earth or flex is the most suitable cable

 

Thanks, i was unsure what to do with the remaining earh wire that will be unused ? simply chop off or pull out ?

[Kev.O]

Chop it off

[Supra-Brett]

Chop it off

 

many thanks mate

[Kev.O]

No problem

[merckx]

When I use twin and earth for 12v dc I bend the earth back onto the grey sheath of the t & e and wrap it up with some insulation tape.

 

I don't like to leave a sharp cut off earth wire.

[kjgreen3]

Yep 1.5mm2 Twin and earth will be fine, as an electrician I use it all the time for downlights as long as that circuit is fed from a fuse/breaker with a rating NO HIGHER than 10amps.

 

You could just use one junction box and link to the first transformer, then link transformer 1&2, 2&3, 3&4 ...... to number 6 (making sure to keep earths connected, use a connector block and some earth sleeving). The earth wire is important as its there to protect the cable as well as you from a shock hazard, so you need to keep continuity until the last accessory. You dont need earth on extra low voltage (ie 12V) so its can be cut back or taped up as previously suggested from the transformers to the downlights.

 

One thing to do is to make the transformers accessable as they can stop working after time so you may need to replace them, give a bit of slack in the cable so you can pull them back through the downlight hole to change them if necessary.

 

Ok if you are fitting them in a ceiling or wall the main thing to remember will be to have a MINIMUM of 5 cm around the downlight free of insulation and flammable material (Joists, lattes, noggins etc) as they do give off a lot of heat. So dont drill too close to joists because it can be a fire risk. The plasterboard is ok though as its pretty heat resistant.

 

HTH

[formatzero]

Yep 1.5mm2 Twin and earth will be fine, as an electrician I use it all the time for downlights as long as that circuit is fed from a fuse/breaker with a rating NO HIGHER than 10amps.

 

You could just use one junction box and link to the first transformer, then link transformer 1&2, 2&3, 3&4 ...... to number 6 (making sure to keep earths connected, use a connector block and some earth sleeving). The earth wire is important as its there to protect the cable as well as you from a shock hazard, so you need to keep continuity until the last accessory. You dont need earth on extra low voltage (ie 12V) so its can be cut back or taped up as previously suggested from the transformers to the downlights.

 

One thing to do is to make the transformers accessable as they can stop working after time so you may need to replace them, give a bit of slack in the cable so you can pull them back through the downlight hole to change them if necessary.

 

Ok if you are fitting them in a ceiling or wall the main thing to remember will be to have a MINIMUM of 5 cm around the downlight free of insulation and flammable material (Joists, lattes, noggins etc) as they do give off a lot of heat. So dont drill too close to joists because it can be a fire risk. The plasterboard is ok though as its pretty heat resistant.

 

HTH

 

Excellent advice,also make sure you keep your twin and earth well away from these lamps.Im currently trialing a couple of 12v l.e.d lamps 4watt among my halogens 20watt light output is almost identical,but they run much cooler,a lot more expensive at over £17 each

[Supra-Brett]

Thanks everyone. Ive left plenty of slack and airspace etc.

 

I went to the electric centre as i went past and picked up 6 x new transformers on offer at £3 each. They have the wires built in so i no longer need to faff about. I took the screwfix ones back.