Wiring Halogen lights

[Delgado]

Hi all,

Now, before I start I'd just like to say that I know just enough about electrics to make me dangerous, but I'm looking to put up some 500w halogen security lights with PIR sensors. I'm going to put up 3 units, 1 of them will be about 4 meters from the box, and the other 2 will be about 30 meters away. The cable will be run inside the building mostly clipped to the wall as it's an old farmyard type building, and also on the outside walls up to the lights. I think I can handle it, if I can't then I'll just run all the cables etc. and have a spark connect them into the box.

Got a couple of questions;

What size breaker (RCD?) do I need?

Will it make a difference if I mount them higher than the recommended 2.5 meters, as Idealy I want them at about 3meters?

What size/type of cable would be best?

Cheers!

 

[tigler]

Use a 10 amp MCB and 1.5 mm T&E cable to the vicinity of the light, terminate that in a junction box, then connect to the light with 5 amp minimum flexible 3 core cable. If any of the cable run is at risk of mechanical damage, the section at risk should run in conduit.
Are you confident about connecting to the consumer unit ? If not let a sparks do it.
Installation height shouldn't be an issue unless there are any overlooked properties that could be affected by light pollution.

 

[Delgado]

Use a 10 amp MCB and 1.5 mm T&E cable to the vicinity of the light, terminate that in a junction box, then connect to the light with 5 amp minimum flexible 3 core cable. If any of the cable run is at risk of mechanical damage, the section at risk should run in conduit.
Are you confident about connecting to the consumer unit ? If not let a sparks do it.
Installation height shouldn't be an issue unless there are any overlooked properties that could be affected by light pollution.

Thanks for that, just had a quick look online and it seems that 0.75mm flexible 3 core is rated at 6amps so I'll get some of that along with the T&E.
None of the cable should be at risk, and I'm gonna run it up high just to be on the safe side.
Light pollution shouldn't be a problem as there's no-one living near by, so I'll mount them a bit higher and possibly put them in cages to stop people tampering.
With regards to the consumer unit, last time I took one apart it looked pretty straight forward, but as you say, if I take the cover off and feel that I'm out of my depth I'll just get a spark to do it.

Thanks again!

 

[tigler]

Consumer units are simple enough but I thought is best to be sure and ask
I have seen some pretty scary stuff from amateur attempts at wiring, some people can't even wire a plug !
I presume you will be installing switches ?
Stringing that lot up should keep you occupied for a while !

 

[the snooper]

the recomended 2.5 meters is the height the pir works best

 

[Delgado]

Consumer units are simple enough but I thought is best to be sure and ask
I have seen some pretty scary stuff from amateur attempts at wiring, some people can't even wire a plug !
I presume you will be installing switches ?
Stringing that lot up should keep you occupied for a while !

Ahh, good point about the switches, nearly overlooked them
I think I'm gonna knock up a quick sketch and post it on here tomorrow just to double check that I'm on the right track.

the recomended 2.5 meters is the height the pir works best

Makes sense, thanks for pointing that out. They should still work ok if I put them a little bit higher though, no?

 

[brightspark]

Ahh, good point about the switches, nearly overlooked them
I think I'm gonna knock up a quick sketch and post it on here tomorrow just to double check that I'm on the right track.



Makes sense, thanks for pointing that out. They should still work ok if I put them a little bit higher though, no?

the higher u put them the lower the tilt has to be . in other words at normal height they pick up in a fan out to 12 meters if there higher they still pick up the same distance but they will be a gap underneath about 45 degrese from the censor that wont be covered

 

[Delgado]

Ok, I get ya. The one that I was most concerned with will be by the front gate, about 4meters across and 3-4 meters up on a bracket on the side of the wall. So, from what you're saying, it'll still be well in range and if tilted down a little bit will still give good coverage, although I'm sure I'll be up and down the ladder a few times to get it tilted right.

Cheers

 

[tigler]

Or, you could use a seperate sensor so the light can be as high as you need but the sensor can be ideally located for best coverage ?

 

[Delgado]

Or, you could use a seperate sensor so the light can be as high as you need but the sensor can be ideally located for best coverage ?

Good Idea, but I've already ordered the lights with built in PIR


Here's a quick sketch of what I'm planning to do...

View attachment Lighting.bmp

 

[jugs]

I've got a PIR compact fluorescent flood mounted @ 3,7m over the workshop door - works fine , picks up any bodily movements within 20' rad & on goes light .

 

[Delgado]

I've got a PIR compact fluorescent flood mounted @ 3,7m over the workshop door - works fine , picks up any bodily movements within 20' rad & on goes light .

Nice! Seems like the general consensus is that it won't be a problem then.

 

[Delgado]

Here's some pics of the electrical supply and consumer unit that's already in there. Think that I can see a couple of 64a 3phase sockets on the horizon too (Obviously I'll get that done by a pro).






One thing that I'm a bit confused about is that the feed to the consumer unit says 63a (photo2) the main switch on the consumer unit says 40a, but then the consumer unit says max 100a, which I'm guessing to mean that you cant put more than 100a worth of MCBs (in total) into it? Surely if I had everything running at once it would trip the 40a or 63a breaker?

 

[tigler]

Yes, I can see the reason for confusion. The consumer unit can handle a maximum load of 100 amps, but it is fitted with a 40 amp breaker, although it could have upto a 100 amp if required. The Isolator switch that serves it has been selected to handle more than the consumer unit has been set to, normal practice as it's a secondary level of protection.

 

[Delgado]

Yes, I can see the reason for confusion. The consumer unit can handle a maximum load of 100 amps, but it is fitted with a 40 amp breaker, although it could have upto a 100 amp if required. The Isolator switch that serves has been selected to handle more than the consumer unit has been set to, normal practice as it's a secondary level of protection.

Ok, makes sense now, thanks for clearing that up!