cable choice for new downlights

[RF Lighting]

0.75mm² flex is not big enough for a 2kW load

 

[sidb]

I found the silicone insulated cable, RS Components part 192-7940. Thank you.

This cable is rated to 180°C, so much more suitable for use near a hot lamp. Whether it would survive prolonged direct contact with a halogen bulb, I suppose I could find out by experiment on the kitchen table.

Anyway, thanks for pointing out the issue of heat put out by these halogen downlights!

 

[bernardgreen]

0.75mm² flex is not big enough for a 2kW load

I know that

It was for diddy little down lighters so 0.75 is adequate from lamp to a JB far enough from the clamp to remain cool where the PVC cable suitable for the total load is run.

 

[bernardgreen]

I found the silicone insulated cable, RS Components part 192-7940. Thank you.

This cable is rated to 180°C, so much more suitable for use near a hot lamp. Whether it would survive prolonged direct contact with a halogen bulb, I suppose I could find out by experiment on the kitchen table.

Anyway, thanks for pointing out the issue of heat put out by these halogen downlights!

Sorry I couldn't look up the RS part number for you.


The idea even with silicon cable is to keep the cable away from the bulb as much as possible.

 

[RF Lighting]

0.75mm² flex is not big enough for a 2kW load

I know that

It was for diddy little down lighters so 0.75 is adequate from lamp to a JB far enough from the clamp to remain cool where the PVC cable suitable for the total load is run.

Sorry, I mis understood what you were getting at.
0.75mm² is fine for DLs

 

[philrosenberg]

Thanks for the suggestion, but I don't see how 3-core flex offers any advantage over twin-core+earth cable. Being the lazily person I am, I don't want to bother joining the earth wires together all the way along the light run.

Possible reasons that I can think of for needing an earth wire are:
a) regulatory
b) safety (in this case I am using double-insulated fittings)
c) future-proofing, for changing or adding light fittings later on.

And as far as I can tell, (c) is the only valid reason.

You are correct, only reason to use earthed cable is future proofing. But it's much easier to connect the earths up now than use twin cable and have to rip it all out later if you have to change a fitting and it needs earthing

 

[plugwash]

0.75mm² flex is not big enough for a 2kW load

well 0.75mm PVC flex isn't........

i'd imagine that given that silicone flex will withstand hits from a soldering iron its response to running at high temperatures is rather different from pvc.