300w FLOODLIGHT WIRING INTO MAIN RING

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Hello

I've just taken advantage of the Homebase 10% discount and bought a 300w floodlight with PIR for the rear garden.

I have managed to fix it to the wall and connect a twin and earth wire from the floodlight to a 5amp FCU. I was then going to get its supply from the ceiling rose in the utility room when I read the instructions and discovered that this is not recommended and that the supply should be obtained by breaking into the main ring.

The only problem is, what is the main ring? is it the supply wire to the ceiling rose? or not and how do you know which is the main ring and break into it?

Please help.

Thanks.

 

[spark]

They probably recommend you don't use your lighting circuit because it may in some cases overload it; 300W is roughly equivilant to adding 5 more typical lights to the lighting circuit. You could be safe depending how your lighting circuit is at the moment. The ring main is the power circuit generally supplying socket outlets in domestic premises. You will usually have (depending on the size of your house) a ring for upstairs and a ring for downstairs. Some house are wired to give a ring for the front and a ring for the back and you may also have a ring just for the kitchen. How many lights (and what rating is each of them) are on the lighting circuit you had intended to use?

 

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The house is a terraced property which was rewired about 15 years ago. The consumer unit shows that there are two rings for the lighting circuit, one for upstairs and one for downstairs. There is only one ring for all the sockets in the house.

The lighting circuit downstairs is the one I intended to use and has 7 lights each rated at between 60-100w. The total rate currently for the whole of the downstairs lights is 660w. Upstairs there are 4 lights each one rated at 100w, in total 400w.

Please advise if I should go ahead as planned.

If you advise that I should break into the main ring, can I just connect the supply wire for the floodlight from the FCU to any socket within the house?

Thanks.

 

[spark]

You can use your downstairs lighting circuit (not a lighting ring but I knew what you meant) in that case; even if every light on the circuit is on at the same time (including the flood), it will still be less than 1kW which is fine, even on a 6A breaker.

 

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Thanks for all your help Spark, sincerely appreciated.

Regards: Jason