electrical help

[trent1579]

i am intending to installing a 500w pir to lighting circuit,there are 4 lights down stairs,1 boiler and 1 room thermostat so there is enough watts available to add a 500w light,my question relate to wiring,

could someone please advise me how to do it
cheers

[cablefreejunkie]

You basically need to taka a permanent live earth and neutral supply to the pir light
From the most easily accessable lighting point
Without seeing its hard to advise
It may be easier for you to come directly from the consumer unit
Again without seeing its hard to advise
You must make sure that you come off the permanent side of the lighting circuit and not the switched side As the light will not function correctly,,if in doubt get a sparky
Any more info required let me know

[matrixabc]

Use a plug!

i am intending to installing a 500w pir to lighting circuit,there are 4 lights down stairs,1 boiler and 1 room thermostat so there is enough watts available to add a 500w light,my question relate to wiring,

could someone please advise me how to do it
cheers

the best way would be to wire it to a plug with a three core flex, with a 5A fuse and just plug it in, this way it doesent contravine part P regs and is safer than going into your consumer unit , or overloding your lighting circuit.

rgds
Al.

[cactikid]

yes i wired mine to a 3 pin plug as 500 watts is quite high and i lowered mine down to 200-300 watt for outside of house

[chucklor]

The usual rule of thumb with lighting circuits is that we do not put more than a 1000watts total per cicuit, so say 10x100 watt lights=1000w, so you say 1000w/230(mains voltage)= approx 4.5 amps, which if you look in your consumer unit(fuse box) the lighting will be 5 or 6amps,so it can carry the cuurent safely. If you take it off any ring main or radial you will have to put a switched fused spur in and put a 5amp fuse in the fuse carrier(they come supplied with a 13amp). You can run it in the correct flex with a 13amp plug but again change the fuse rating to 5amp and sometimes you can suffer from scorching on the live pin of the 13amp plug...chuck

[cablefreejunkie]

The usual rule of thumb with lighting circuits is that we do not put more than a 1000watts total per cicuit, so say 10x100 watt lights=1000w, so you say 1000w/230(mains voltage)= approx 4.5 amps, which if you look in your consumer unit(fuse box) the lighting will be 5 or 6amps,so it can carry the cuurent safely. If you take it off any ring main or radial you will have to put a switched fused spur in and put a 5amp fuse in the fuse carrier(they come supplied with a 13amp). You can run it in the correct flex with a 13amp plug but again change the fuse rating to 5amp and sometimes you can suffer from scorching on the live pin of the 13amp plug...chuck

if you have lv downlighters which i think you mentioned in your pm a 10amp mcb will be more suitable,toroidal transformers seem to trip 6amp mcbs quite readily,,most lighting circuits are fine to run at 1200 watts(i install lots of them) 10 amp mcb is fine aswell,your 1.5mm lighting cable is rated up to 18 amps,,this does not mean you load it up to 18amps,but 10 would be fine