Hello,

I was reading the excellent wiki faq and I noticed it says that
1.5mm^2 T&E can be used for high power lighting circuits and 16A
radials.

What is the definition of "high power" lighting: several 500W outdoor
PIRs? Before anyone shouts about using 500W bulbs, I use 150w myself


I think I've always used 1.5mm^2 rather than 1.0mm^2 for all lighting
but then I've only ever used a bit. If I was wiring several hundred
metres a day, I'm sure I would quickly use the cheapest and safest
cable. Is 1.0mm^2 commonly used?

Can I ask about the 16A radial bit? I know that 1.5mm^2 T&E is rated
for IIRC 16A (provided it is clipped direct to the wall and not in
conduit, insulation, etc.) but doesn't it have a smaller earth
conductor? I thought it had 1.0mm^2 "earth" whereas 2.5mm^2 T^E has a
1.5mm^2 central conductor doesn't it? Doesn't the smaller earth wire
have implications? I remember reading the "taking electric outdoors"
and I am sure earth impedance was an issue there. Why isn't the
smaller earth an issue on 16A radials?

Is it commonly used for radials or do pros use 2.5mm^2 for everything?
At least that way you are protected if someone decides to do something
wrong in the future (e.g. spur off a spur).

Thanks,
Stephen.