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Old 11-19-2007, 04:42 AM   #16
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Just you fellas in the US have such a thing called a Maximum Demand calculation? In Australia, it is a part of the Wiring Rules & must be adhered to.

Generally speaking, a standard single story 3 bedroom home that occupies no more than 5 people, will have a standard 80 Amp supply (at 240v single phase). Of course, this translates to about 160 Amps at 120v single phase.

If in doubt, the electrician performs a Maximum Demand calculation, which can be done using a few different methods.


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Old 11-19-2007, 05:58 AM   #17
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Sure, we do what is similarly called a "demand load calculation", or "load calc" for short. This is Article 220 in our NEC.

We don't use the 80a@240v = 160a@120v analogy though. This is really a meaningless number over here.
Residentially it's just 100A service, 150A, 200A, and 400A (really 320A) services.
120/240v single phase is assumed for residential.
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Old 11-19-2007, 08:29 AM   #18
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I heard from 2 sources now that our local POCO will not allow less than a 200a service on any residence. 100a services allowed only for freestanding signs and in multiple occupancy dwellings like apartment/co op complexes.

IMHO it's overkill when a residence is heating, cooking, and clothes drying with gas, but there are no exceptions when alternate fuels are available and utilized. I do agree however that an underground service should be 200a, even if the lower 1/2 was only 100.
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Old 11-19-2007, 12:13 PM   #19
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here our POCO useally ask min of 100 amp 1 supply for all loads [ both resdentail and commercal]

but for 3 it will usally ask for 200 amp but no longer provide delta connection for new comusters.

but instering twist with UG [ underground ] service it automatically 200 amp [or larger]reguard which phase system you use.

Merci, Marc


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