downlighters

[chunkymonkey]

is it safe to use .75mm cable to power downlighters, i know 1mm is the recommended size, but i have plenty of .75 and local stores do not seem to stock 1mm. the downlighters permanent live supply is coming from the main central light into a dimmer switch, then obviously to the first light. the lights are dimmable and they are the non transformer kind. what are the dangers of using .75 instead of 1mm.
thanks

 

[Chri5]

I take it that your fitting 230v GU10 50w units ??

If so, how many ?

We need to calculate the load on the cable, so say your fitting 8 units-

8 x 50w = 400w / 230v = 1.8 A (approx.)

So what type of 0.75mm cable is it ?

3 core (earth must be included) 0.75mm is rated at 6A, so IF my assumptions are correct regarding unit numbers and cable type it will be fine to use the cable.

Please make sure the cable is run in and out of each connector at the unit with care to avoid the heat the lamp will produce.

 

[ban-all-sheds]

the downlighters permanent live supply is coming from the main central light into a dimmer switch, then obviously to the first light. the lights are dimmable and they are the non transformer kind. what are the dangers of using .75 instead of 1mm.
thanks

This is permanent wiring, why on earth are you contemplating using flex for it?

If your local store doesn't have 1.0mm² twin & earth then buy 1.5mm²....

 

[Pensdown]

This is permanent wiring, why on earth are you contemplating using flex for it?

You should get with the EU programme. There is nothing wrong with flex for fixed wiring, if you like that sort of thing.....

 

[chunkymonkey]

thank you guys, however this earthing is confusing me a little, the lights according to instructions do not need earth, and there is no place for earth cable. the .75mm i have is just 2 core. the power going to the dimmer switch is coming from the main light in centre of room, (which is earthed) it is actually a fan light (soon to be replaced with just a fan) the new dimmer switch has no earthing point on it either. the lights are indeed 50w GU10 and i may fit a dozen or maybe 14. the lights themselves have a simple L/N connector block inside an outer casing.
all i want to know is how safe or unsafe it will be if i wire them as described.
thanks again for all your help guys [/img]

 

[ban-all-sheds]

Are the light terminals designed to take 0.75mm² flex?

Are the switch terminals designed to take it?

If not then 526.8.1 requires you to prepare the ends to prevent separation or spreading of the individual wires.

 

[chunkymonkey]

thanks for your input ban-all-sheds, not sure what you mean by 'designed' to take .75mm wire. the light connector blocks are of sufficient size, i dont have to force wires in neither is there bags of room, the wire fits neatly. unless of course you meant take it as in power, the light switch i believe is a standard dimmer 400w (i think) have not actually got it to hand as i speak, so it could quite possibly be 600w.
cheers

 

[ban-all-sheds]

Terminals have a minimum size that they can take as well as a maximum - too small and it might not make proper contact with the screw, and also they might be designed assuming solid-core cable.

And check that your dimmer doesn't need to be de-rated for halogen lamps, i.e. it might not be able to support its stated rating with that type of lamp.

 

[chunkymonkey]

ban-all-sheds, thanks for your input. the size of the connector blocks are fine, as i said before, there is no problem fitting the wire, and they are not too big so the wire looks lost in them and not too small so i have to force them in, i also twist the ends well to prevent any strays being left out. the dimmer was bought about 2 weeks ago, and as i already had the lights i am sure i would have made sure it was suitable for GU10. (i will double check though)
many thanks for your input, much appreciated.