Help with Wiring outdoor security light from a loft circuit?

[EFLImpudence]

Is there any requirement to stick a separate 5amp fuse in on this,

No, not if the light circuit, as is likely, is on a 6A MCB - Miniature Circuit Breaker.

or the fact its running on the house RCD

Nothing to do with the RCD.

will suffice with a double pole switch?

Another separate matter, nothing to do with either.

MCB - protects against overloading the circuit and short circuits L-N and earth faults L-E.
RCD - protects against earth-leakage, LorN-E and primarily and more importantly when through a person.
Switch - allows isolation of a fault so the rest of the circuit can function, and, of course, turning on and off.

 

[liam548]

Thanks for the reply. With most lighting for houses now running LEDs the amount of current being used must be vastly lower than just a few years ago.

 

[EFLImpudence]

Yes, it is - and in any case the usual 1mm² T&E was always hugely oversized for 6A.

 

[bernardgreen]

Switch - allows isolation of a fault so the rest of the circuit can function, and, of course, turning on and off

Being pedantic

A switch is for turning on and off but if single pole the circuit is not isolated since the Neutral is not disconnected

An isolator disconnects all conductors other than the Earth wire(s)

 

[EFLImpudence]

Yes, of course, but Liam did say a DP switch.

 

[Harry Bloomfield]

Are there any issues with my plan? I assume I just use the two empty connectors in the box and link it to incoming Live feed as the loft lights have been?

Aside from using a double pole switch, is might be worth your while putting the switch in a more accessible place, if the PIR is of the type where a quick on and off makes the light stay on. It could be handy if you might sometimes need the light to stay on.

Alternatively and instead of the double pole switch, you could fit a 13amp socket to the lighting circuit and wire out to the light with flexible cable and a 13amp plug. Unplugging provides an even better/ more certain way of isolating the light completely and makes it possible to add a plug in Smart Socket for control via Alexa - facilitating automatic and manual remote control of the light.

I have four such lights working via a couple of Smart Sockets. Three just remote control, one comes on dusk until 11pm under control of Alexa.

If you are considering mounting the PIR operated light up by the eaves of a two story house, be aware that a PIR may not work as well working from that angle.

 

[liam548]

Aside from using a double pole switch, is might be worth your while putting the switch in a more accessible place, if the PIR is of the type where a quick on and off makes the light stay on. It could be handy if you might sometimes need the light to stay on.

Alternatively and instead of the double pole switch, you could fit a 13amp socket to the lighting circuit and wire out to the light with flexible cable and a 13amp plug. Unplugging provides an even better/ more certain way of isolating the light completely and makes it possible to add a plug in Smart Socket for control via Alexa - facilitating automatic and manual remote control of the light.

I have four such lights working via a couple of Smart Sockets. Three just remote control, one comes on dusk until 11pm under control of Alexa.

If you are considering mounting the PIR operated light up by the eaves of a two story house, be aware that a PIR may not work as well working from that angle.

Great ideas yes. With the outdoor garden socket we are having fitted this year Im purchasing a wi fi socket which can be turned on and off remotely. Great for garden lights.

The security light im getting as per this post is simply for the side of the house so a standard 5 min timer will probably do the trick, i cant see a time when Ill need to turn it on and leave it on. Its simply a side path from front to rear. Although I will at least leave the switch somewhere mounted in the loft that I can use, (just not to next to the loft light switch to avoid someone turning it off by mistake).

If I was to wire in a plug socket from a lighting circuit I think id be best putting a 5 amp fuse in the plug in that case? (not that Im going to just want to check my understanding)

 

[Harry Bloomfield]

If I was to wire in a plug socket from a lighting circuit I think id be best putting a 5 amp fuse in the plug in that case? (not that Im going to just want to check my understanding)

If the socket is connected to the lighting circuit and properly marked up, to indicate it is only for the outside light, and the outside will only be plugged into that socket, then even a 13amp is unlikely to blow before the 6amp MCB were to trip - but yes, fit a 5amp fuse just in case.

Access to my loft is via a loft ladder, alongside the airing cupboard. I mounted the loft light switch at the side of the airing cupboard, close to the ceiling. That makes it easier to switch the lights on and if I have doubts as to whether I turned the lights off, after closing the hatch, I can just glance at the switch to check.

 

[Tigercubrider]

Second vote for an accessible dp switch to allow the light to be forced "on" in daylight/all night.
A quick flick of the switch off/on can be useful and even if hardly used takes little effort.
It saves entering the loft if the lamp blows ( not sure if you are planning LED of halogen?)

 

[bernardgreen]

Those PIRs with the quick OFF - ON override function can get turned ON by transient power cuts.

Installing three core + Earth cable would future proof the installation for adding override switches at a later date ( when the PIR gives up )

 

[liam548]

All done and working well. Thanks for the assistance all.

Freezing up there today!