PIR floodlight - mains or lighting circuit?

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Hi there,

I have bought one 400W and one 120W PIR floodlight (one for the front and one for the back). I am torn between wiring them up to the lighting circuit, or via a fused spur from the mains. Can anyone give me a definitive list of pros / cons? The downstairs lighting circuit (which I would use in both cases) has a lot of individual lights but they're all 240v low wattage LEDs - probably about 30 in total, apx 5w each.

What do you think?

I will also want to install an override switch so that I can have the lights on permanently, but that seems to be covered off pretty well in other posts.

Thanks!
 
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The 400 watt may require building regulation approval to be fitted on an external wall.

The supply choice should consider what will happen if a lamp is damaged / saturated and trips the circuit off. Connecting to the lighting circuit would leave you in darkness until you were able to isolated the damaged lamp ( fit a double pole isolator ) and reset the trip but at least you would soon know something was amiss.

Connecting to a power ( sockets ) circuit could leave appliances such as freezers without power until you realised something was wrong with the floodlights.
 
Thanks bernardgreen, very helpful. I don't suppose that putting a 3A fuse in the FCU would get around the issue you identified?

Does anyone have a diagram I could use for wiring up an override switch? Ta
 
Thanks bernardgreen, very helpful. I don't suppose that putting a 3A fuse in the FCU would get around the issue you identified?

Does anyone have a diagram I could use for wiring up an override switch? Ta
 
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A FCU would provide double pole isolation.

As regards to override wiring what make and model of light have you purchase? most these days have built in override function.
 
They're cheapo ones from a shed whose name starts with W. Cost me a tenner each. I didn't see anything in the instructions about an override function, but it may be possible. Thinking about wiring up an override switch in any case, just can't work out how...
 
If it is the Shed I am thinking of, I believe these lights are going to malfunction on you very shortly and you will not need an override switch as they will be permanently on!
Best advice I can offer is return them and buy a quality product, they don't cost a fortune to buy.
 
You are probably right. But what if I still wanted to install such a switch on the offchance that they do work?
 
L, N and Earth/CPC from FCU to switch. then 3 core and earth to PIR.
Brown is perm L to PIR, black from switch to PIR out. grey N sleeved blue, then L and N from PIR to light.
All earths/CPCs to earth terminals.
 
This is the circuit

The 3 amp fuse would protect only against overloads. The most common problem with external lamps is earth leakage due to dampness from Live and / or Neutral and this trips the RCU. it will not blow a 3 amp fuse
 
Hi there,

I have bought one 400W and one 120W PIR floodlight (one for the front and one for the back). I am torn between wiring them up to the lighting circuit, or via a fused spur from the mains. Can anyone give me a definitive list of pros / cons? The downstairs lighting circuit (which I would use in both cases) has a lot of individual lights but they're all 240v low wattage LEDs - probably about 30 in total, apx 5w each.

What do you think?

I think you should return them and get LED ones which use a lot less power.
 

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