Wiring a PIR floodlight

[R Stringer]

Hi all,

I’m looking for some advice regarding the best way to wire a 54W PIR floodlight to my garage. I have used the floodlights pre installed 1m of cable to enter the garage and added 1.0mm T&E cable via a choc bloc inside an in-line connector box.

The garage is powered from a radial coming from the house fuse box via armoured cable into a SFCU.
From the SFCU is a double socket powered from the supply side and a ceiling light from the load. This was all completed by the builders and is shown below;



I’m looking to power from the floodlight from the radial. I would like the floodlight to be permanently live so it can operate from by its PIR. It would be nice to override the PIR when required to have it permanently on but I don’t think that’s possible? I have looked into options and unless I’m incorrect they are;

1. From the SFCU add a 2 gang switch. Wire the floodlight into one switch which would be left switched on permanently (still allowing isolation if needed) and the existing ceiling light into the other switch.



2. Spur from the supply side of the SFCU into a another SFCU/Unswitched FCU with 3a fuse. Wire the 1.0mm T&E from the floodlight into the load of the new SFCU. As below



3. Replace everything with a grid switch with 3 modules; 3a fuse - switch - switch. This would probably look neatest but I’m not entirely sure how to wire a grid system. Would it be line into the fuse then loop into switch 1 then switch 2? Neutrals into terminal block and earth terminal on the back box?

I’m happy enough to do this myself, I’d just like to see which option appears best and make sure everything is correct. I have considered sticking on a plug with a 3a fuse and plugging it into a socket but would rather keep them free for appliances.

Thanks in advance.

 

[terryplumb]

If there is a neutral at the existing light switch ,then pick up the supply from there to your new light.
Is there RCD protection on all garage circuitry ?
If I have understand your description correctly all the existing socket/ light are fed from a switched ,fused connection unit ,presumably fused at 13amp ?

 

[R Stringer]

Hi Terry, thanks for your reply.

Yes the garage is RCD protected at the consumer unit in the house.

The existing light is fed and switched on/off by the switched FCU with a 3amp fuse. The socket is fed from the supply side of the FCU and not fused.

I can’t go from the load side of the FCU as the switch controls the inside light, which would also turn off the security light.

 

[terryplumb]

Only one double socket ?
What size cable from house to FCU and from there to socket ?
What is the OCP ,( and its amperage )?
You may be able to go from socket to SFCU / to new light.

 

[R Stringer]

Yeah just one double socket.

The OCP is a 16a MCB at the consumer unit

cable from house to FCU I believe is 2.5mm T&E (apologies garage is not connected to go check)

cable from FCU to double socket is 2.5mm T&E.

They also used 2.5mm T&E from FCU to light.

 

[terryplumb]

Extend from socket in 2.5mm² T &E to a switched fused connection unit.
I assume you don't plug anything into the sockets that draws high current ,not that your new light adds anything worth talking about load wise.

 

[R Stringer]

Thanks Terry - really appreciate the help.

currently, no, the sockets are only used for a lawnmower.

Would there be any difference going from the existing FCU into another FCU rather than the socket? Reason being it’s much closer to the security light and would save me buying more cable.

 

[terryplumb]

You can ,or if easier introduce another SFCU after the first and before the socket ,all connected in 2.5mm into each ones supply terminals. So only the light fittings connected to each SFCU load terminals ( one light to each).
The connection units could be next to each other.

 

[winston1]

You can ,or if easier introduce another SFCU after the first and before the socket ,all connected in 2.5mm into each ones supply terminals. So only the light fittings connected to each SFCU load terminals ( one light to each).
The connection units could be next to each other.

The second FCU has to come off the supply side of the first not the load side as the load side is switched.

 

[terryplumb]

That's what I said Winston ??

 

[R Stringer]

Thanks fellas. I’ll do that so it’ll look like this;