Outside light help

[dubspark]

Hi all, newbie question time
Been very kindly asked to fit some halogen lights up in a yard used for a private hire cars. They want a sensor over the entrance gate with a 300W lamp and 2 more over the yard, both will be 500W. Total lengh of run is around 38m, can I use 1.5 mm singles run in plastic conduit, and will I need to make them run of there own circuit? Sorry to ask, many thanks

Steve

 

[bugsy]

It would be easier , quicker and cheaper to use 1.5 3c swa

 

[simon1]

no problem with cable type or size.if you need a new circuit will depend on how much current is on the existing one. You are allowed up to 14 amps on a 1.5mm single in conduit, if you use 1amp per 250watt of load as a rule of thumb you wont go far wrong

 

[GT1]

I would defo go for a new circuit from the DB if at all possible..
however if thats too much a pain a fused connection unit could do just as good a job off an existing circuit so long as no problems with loading.

 

[bugsy]

no problem with cable type or size.if you need a new circuit will depend on how much current is on the existing one. You are allowed up to 14 amps on a 1.5mm single in conduit, if you use 1amp per 250watt of load as a rule of thumb you wont go far wrong

But dose'nt beat doing the actual calculation !

If use rule of thumb all time you might just forget how to

 

[simon1]

i agree you cannot beat doing the actual calculation, but to do that with any precision it requires taking an accurate voltage reading.to take it for granted that you are working with 230v is wrong as i rarely get this when testing, more often than not i find voltages of 240v + are the norm

 

[dubspark]

Thanks for the replies, you can tell I'm a newbie, just get the reg's book out......doofus
There is one 500W light with pir already there, its old so someone has just cut the cable off, that was just fed with normal T+E 1.5mm, that was fed from an old rewirable fuse held in with some insulation tape, and it was still live!!

As I have never put up more than 1 light before. Do you connect to the stand alone pir sensor, am I right in thinking you then link up to each light?

Steve

i agree you cannot beat doing the actual calculation, but to do that with any precision it requires taking an accurate voltage reading.to take it for granted that you are working with 230v is wrong as i rarely get this when testing, more often than not i find voltages of 240v + are the norm

Cheers fella, yes its 230.

 

[simon1]

correct steve there is a live in and live out in sensor

 

[GT1]

Do you connect to the stand alone pir sensor, am I right in thinking you then link up to each light?

Depends how you want them to work..
Do you want them all to come on with that one PIR..?
Maybe split the yard into two..?

Are they being used for security, or to light the yard when people are working. If so you need an overide switch.
Your guy may appreciate an override anyway.

Just a note.. you may want to take the opportunity to replace that PIR if its been there a while..
I find loads that just break down and fail after a time.. sometimes a short time at that..!!

 

[dubspark]

Depends how you want them to work..
Do you want them all to come on with that one PIR..?
Maybe split the yard into two..?

Are they being used for security, or to light the yard when people are working. If so you need an overide switch.
Your guy may appreciate an override anyway.

Just a note.. you may want to take the opportunity to replace that PIR if its been there a while..
I find loads that just break down and fail after a time.. sometimes a short time at that..!!

Thanks for the reply GT1, yup, that old light is being done away with. The main job for the lights is to give some light for when they have to do late night airport runs.
Just had a rethink after what you said about split the lights up, its an L shaped yard, I could have one over the main gate and at the bottom of the L, and then another one at the top of the yard.