2kW lighting circuit!!

[YanisTheYak]

Hi

I've just started to rewire our house - everything is new after extensive refurbishment.

We have decided that we would like the kitchen and lounge to have recessed lighting probably the LV version.

I've done a few calculations and adding up all the lights for the downstairs section of the house I get
somewhere around 2000W (20 Halogens @ 50W, and 10 bulbs @ 100W)

Using W=V*A...

2000=240*A => A=8.5 amp (ish)

way over the 5 or 6 amp of a normal lighting circuit.

My first thoughts were to split the downstairs lighting circuit into two, trouble is I have the same problem upstairs - the entire upstairs requires recessed lighting as it is a loft conversion. So I would end up with 4 lighting circuits - fine except I have already used up all 11 fuse ways on the consumer unit.

I am now starting to think about beefing up the lighting circuit and using 2.5mmsq wire and a 15 amp MCB at the consumer unit, as long as I use the corrected rated components and junction box wiring I should avoid overloading. I can't actually see anything wrong with this approach but does anyone out there know a reason why this would be a bad way to proceed?

Any comments greatly appreciated

Ian

 

[spark]

You will have a hard time terminating the 2.5mm cables in certain lighting accessories. If you have any 2-way switching, you'd have to try to get hold of some 3core+earth 2.5mm cable (I've never seen it before). There are lots of I reasons why I wouldn't recommend using 2.5mm cable for lighting. Why don't you use a 10A circuit breaker if you're stuck for space in the consumer unit? If you wire it in 1.5mm cable a 10A MCB will be fine, you just won't have much room for manouvre if you want to put more lights on the circuit. Just for your peace of mind, 1.5mm T&E will take 19.5amps installing it in a typical house (open&clipped direct or embedded directly in building materials), even worst case scenario (enclosed in an insulated wall) it is capable of taking 14amps.

 

[breezer]

If you use low volltage lights (you said you may) your calculatoins will be different since you will only need to worry about the primary side of the transformer.

another thought if you do use lv lights get dimable transformers

 

[YanisTheYak]

Thanks for your responses. I wasn't sure what the maximum rating of 1.5mmsq was. I'll proceed with that.

As for dimmer compatable transformers I've already bought ones that should be OK with a dimmer.

Cheers!

 

[spyder]

be sure when you get your dimmers they are electronic (expensive) ones as the normal dimmers wont work.