Help Needed!!

[Sparky_2607]

Hi there, first post so be gentle!

Now i have had some work set by my college and I just needed your help to check wht i have done is right. So the question is:

How many lights (60 and 100W) can you run off a 6 amp MCB in a domestic home?

Now I have worked it out to be,

230*6 = 1380

1380/60 = 23

1380/100 = 13.8

so

60W is 23 lights in a domestic home

100W is 13 lights in a domestic home


So i ask you, is this correct and if not, could you direct me as to where i have gone wrong?

Many Thanks (sorry its long winded)

 

[Sparky_2607]

Anyone able to help?

 

[Ceekay]

Hi Sparky,

You dont need any help, what you have done is correct. We used to say 1KW (1000 watts) was 4amp just for ease but on actual figues using 230v you are spot on. Obviously a standard 1.5mm square twin and earth will carry considerably more amps than that so could in theory be fused at a higher rating if more load was required depending on exactly what type of lighting was involved etc.

 

[Risteard]

You should assume 100W at each point (not 60W).

Although, with application of diversity you could increase what you are supplying from a 6A circuit breaker.

 

[Ceekay]

Yep sorry about that, Risteard is right. Although your calculations are correct the regs (including the on-site guide) state you should assume a min of 100w at each point. Should have remembered they always try to catch you with that one. Long time ago.

 

[ezzzekiel]

Dont think they will expect diversity to be applied either

 

[SirKit Breaker]

Sparky 2607, i agree with your calcs, but just to keep you on your toes I will throw one back to you. Which 6a MCB would you use in that installation and why?, Type B,C or D.

Cheers..........Howard

 

[Sparky_2607]

Type B as these are mainly used for domestic and light commercial lighting?