Installing a new outdoor floodlight

[dj316]

Hi

I'm looking at the idea of replacing an existing outside bulkhead light at the back of my house with a new floodlight c/w PIR detector. The existing light has been wired off the existing lighting circuit and is operated via a light switch in the kitchen.

Basically what I was looking to know is, if it is ok to replace the existing bulkhead with a 500w halogen floodlight, and run it off the existing 1.5mm lighting circuit or would the 500w floodlight be too powerful for the lighting circuit and it would have to be wired with a 2.5mm cable off the general ring circuit.

What I am also looking for is a new floodlight c/w PIR which obviously operates off the PIR but I want to be able to overide the PIR so that the light can be switched on permanently when I need light and when motion is not detected.
I was just wondering if this is possible, I don't know what cables are connected to the outside light as I haven't removed the old light yet, all I know is it is wired off the lighting circuit and is operated via a switch in the kitchen.

Any advice greatly appreciated
Thanks

 

[Spark123]

It depends how much other load there is on the lighting circuit as to wether or not there is sufficient capacity to run a 500w PIR light. (You can try to apply what is called diversity i.e. not all lights will be on at the same time, but I always take this with a pinch of salt).
Is this light for security purposes? Would a 150w one do the job? Some lights have a built in facility where you switch them off and back on within a few seconds they stop on.

 

[ColJack]

as far as i know it's against the building regs to fit anything over a 150W PIR to your house these days?

 

[bernardgreen]

Some lights have a built in facility where you switch them off and back on within a few seconds they stop on.

And come on after short power cuts and stay on till daylight. Unless you life in an area where power cuts hardly ever happen avoid this method of over ride to ON. Your nieghbours will appreciate the difference

So if possible buy a PIR without the overide. Replace the existing 2 core plus earth cable with three core plus earth and change the switch to a two gang switch ( two switches on one plate ) and then the over ride ON can be achieved with the second switch linking live to switched live.

 

[ColJack]

and how often do you get mains "blips" in your supply? I'd talk to your DNO if it's that common..

a "short power cut" needs to be less than a few seconds to overide a light..

please don't advise the OP to start changing cables, from his questions he's not capable of that...

 

[bernardgreen]

and how often do you get mains "blips" in your supply? I'd talk to your DNO if it's that common.. a "short power cut" needs to be less than a few seconds to overide a light..

There is a village a couple of miles from here which gets short cuts three or four times a month. One by one the PIRs are being changed to non overide types. DNO once waffled about it being auto-reclosing after a fault had occured and then instantly cleared itself. Locals suspect the network cannot cope with new building developments.

please don't advise the OP to start changing cables, from his questions he's not capable of that...

I was being optomistic. Perhaps he can advise the electrician to do it.