15 downlights and 10 wall lights help

[paul kilbey]

hi I got my c&g 2330 level 2 and 2392 and just started my c&g level 3 and ive just been ask to do a small job in a converted garage which is 33 ft x 10 ft and has a flat roof any trips


ive got to run the wires for the following

15 down lights on 3 dimmers
10 wall lights on 2 dimmers
2 spot lights on 1 switch
2 outside lights on pir and switch
1 light with switch for store cupboard

thanks paul

 

[c123]

15 downlights and 10 wall lights in a garage. how many watts do they require each?

 

[paul kilbey]

working on the fact that the down lights are 230v it will be about 3000
watts

 

[Mac]

That is a lot of lights mate.I think i would have to run 2 circuits

 

[High Tower]

thats 30 units i wouldnt want to see more than 10-15 units on a supply, even with diversity applied

 

[c123]

yep there are alot of lights you defintely need new circuits. remember power divided by voltage gives you current and 230 v downlighters really suck it big time.

 

[paul kilbey]

thanks guys will run it on two circuits but should i put them both on 10amp mcb or will they be ok on 6amp?

 

[andekoch]

I work on 100w per bulb so 30x100=3000w P=VI so current draw is 3000/230=13A split over 2 circuits means 13/2=6.5A per circuit if equally split so no 2 x 6A mcb's will not be fine in theory (in practice they will probably not trip due to diversity and the bulbs not being 100W but then there are startup peaks etc (which may be overcome by using a type c breaker).

Use the P=VI formulae and the number of lights per circuit and you can work out the mcb size.

Once you know the mcb you will use then select the cable size to make sure it is ok and take note of the derating due to your installation method.

cheers

 

[dixon9]

hi I got my c&g 2330 level 2 and 2392 and just started my c&g level 3 and ive just been ask to do a small job in a converted garage which is 33 ft x 10 ft and has a flat roof any trips


ive got to run the wires for the following

15 down lights on 3 dimmers
10 wall lights on 2 dimmers
2 spot lights on 1 switch
2 outside lights on pir and switch
1 light with switch for store cupboard

thanks paul

Some dimmers only work with a max of 200W - if the lamps are 50W x 5 for each dimmer then watch that - if they are 35W then you are fine.

(Sorry if I´m teaching you to suck eggs here).

 

[patricklondon]

good luck sounds like a nice little starter job. just be aware it will probably take a good bit longer than you expect so include that in your estimate for time