Maximum demand

[peteelecs]

When calculating the maximum demand say for a 3 bedroom house if you cannot use diversity for a 9.5 KW shower how can you keep the total with all other circuits to under 100 Amps? Am I misunderstanding something?

 

[GrannySmiff]

I have asked a similar question and found that its a use your judgment approach, maximum demand is not a 100% exact science as often different electricians will have different views on what the MD will actually be, whether it be by working it out strictly as the OSG states or being flexible and applying some common sense.

Go round your house see how much you could pull if you wanted, remembering also that if it is a 100A fuse from recollection of the time curve characteristics in the big red book you would need to pull something like 150A for 1 hour for it to go, not that I am suggesting you allow 150A to be the MD. Maximum demand is a can of worms, keep reading about it and come to your own sensible decision.

 

[gpz900jim]

you could add all your breakers together and multiply the total by 0.4, thats what i would do

 

[telectrix]

you could add all your breakers together and multiply the total by 0.4, thats what i would do

lot of us do the same. i multiply by 0.5 though in case i've added up wrong.

 

[IQ Electrical]

lot of us do the same. i multiply by 0.5 though in case i've added up wrong.

The good book states: "The use of other methods of determining maximum demand is not precluded where specified by a competent person"

 

[Guest123]

Well it's certainly the time of year that most of our max demand calcs get pushed to the limit. Everyone at home at the same time, heatings on, cooker is flat out, teenagers having 2 hour showers etc.

The proof is in the pudding as they say.