Security Light

[New2Game]

When installing a security light, am i right in saying it needs to be fitted with a switch so that it can be isolated incase of maintence? Or can it be wired directly into the lighting circuit?

 

[JohnD]

Yes and yes. DP switch preferred (not an ordinary light switch) for isolation.

Lighting circuit is best. Please say if you are thinking of wiring it anywhere else as there are other things you need to do.

 

[New2Game]

So a DP switch from the lighting circuit is best? Is that just a straight feed in and out? Whats wrong with a normal light switch???

 

[JohnD]

Normal light switch only interrupts one pole (hopefully Phase

DP switches isolate P+N and are preferable when isolating for maintenance. Especially outside where there is likely to be a voltage between N and T (inside the house N and T, especially in a TNC-S installation that is not faulty, will be almost the same) .

 

[New2Game]

So is a SP switch against regs or simply bad practice? Dont worry i'll use a DP

 

[joe-90]

JohnD (if you don't mind me enquiring). Most instructions re secuity lights say to run from 2.5mm power circuit via a switched fused spur.

I would assume that if someone had 2 x 500 watters connected to the lighting circuit, that this could place rather a strain on a lighting circuit under insulation.

Just wondered what your thoughts on that might be.

 

[JohnD]

Yes, the OP sounded as though he was going to put the lamp on the lighting circuit. The advantage of that is that it doesn't need fusing down. Most domestic PIR lanterns, and photocell lamps with CFLs, will be fine with that.

If you don't like your neighbours, and want to annoy them with dazzling floodlights, a couple of those would take about 4A. If you used 300W tubes, about 2.5A for two.

Depending on how many lamps you have on the lighting circuit, and how many are CFLs and how many are filament, it might be worth putting the externals on a different circuit, or on an FCU with a 5A cartridge in it.

If you have a vast number of huge floodlights, I would be thinking about putting each of them on an FCU with a 3A cartridge, and possibly taking them off a dedicated radial. But that would be outside the scope of most domestic installations. You can also get floods with energy saving tubes, which would save money if you like a lot of light. (a 500W flood costs about 5p an hour to run).

The cables will not be a prob, if they are fused at 6A and run in 1.5mm which has a clipped-direct rating of about 18A, you can de-rate it a lot and still be safe.

 

[JohnD]

So is a SP switch against regs or simply bad practice? Dont worry i'll use a DP

I'd call it poor practice. I can't think of a reg forbidding it though (that may be due to my not having looked for one).

 

[joe-90]

Thanks for that John.

 

[RF Lighting]

I have started to fit ASD smartfloods, which use 1no. 26W PL lamp.

They take 45 seconds or so to get upto full brightness, but when they have warmed up they are IMHO as bright as a 300W halogen floodlight.

Sorry for veering off topic, but I was very impressed at the light output of the fitting while using less than a 10th of the power of a standard floodlight.

 

[securespark]

So is a SP switch against regs or simply bad practice? Dont worry i'll use a DP

I'd call it poor practice. I can't think of a reg forbidding it though (that may be due to my not having looked for one).

AFAICT, there is no requirement in the regs for switching neutrals. It is just accepted as good practice.