600A Single family service conductor size

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steve11777

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I’m looking for some help on calculating the conductor size for a single phase 120/240V single family service. 310.12 only seems to go up to 400A for a single-family service calculation. Would I need to use 310.16 instead of 310.12? I would be installing parallel conductors so could I use table 310.12 and say each conductor will be 300A and do parallel 350MCM AL? If I go by 310.16 it looks like I need parallel 500MCM AL.
 
Good point they can afford the wire but as electricians we always do the minimum required. So it looks like it will be parallel 500 AL if I go by 310.16.
 
TVA rates are still favorable so it's not unusual for us to see power guzzlers such as hot tubs, electric pool water heaters, fast charge EV chargers, instant water heaters to name a few. We see some modest size homes (5,000 sq ft+) loaded with goodies that require services above 400 amp
 
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JoeStillman said:
An all-electric house with 2 kitchens, 2 laundries, and 2 water heaters would have to be 24,000 ft² to need a 600A service.
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You can't say that. You don't know what kind of heating system. Houses with all electric heat and heat pumps can be quite an extensive draw. On demand electric water heaters can draw 80-100 amps alone then 2 or 3 car chargers, etc. Maybe 600 amp is overkill but who knows.

I did a 12,000 sq. ft house with a 600 amp service and maybe I could have gotten by with a 400 amp service but houses like that you never know what they will add. I did a remo on a large home and the steam shower had a 100 amp load..
 
steve11777 said:
It is a high end house with a indoor pool. Lots of HVCA equipment and pool equipment too. When money is no object people can get carried away.
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Last house I did with 600A service had an indoor pool too - with a humidity control system and VRF heat pumps. I forget the square footage, but it was for the owner of an NFL team.
 
Dennis Alwon said:
You can't say that. You don't know what kind of heating system. Houses with all electric heat and heat pumps can be quite an extensive draw. On demand electric water heaters can draw 80-100 amps alone then 2 or 3 car chargers, etc. Maybe 600 amp is overkill but who knows.

I did a 12,000 sq. ft house with a 600 amp service and maybe I could have gotten by with a 400 amp service but houses like that you never know what they will add. I did a remo on a large home and the steam shower had a 100 amp load..
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I figured 2.5 W/ft² for heat pumps, based on my empirical, lived-experience. We're just wagging it here after all. But you're right, I never thought of including car charger(s)!
 
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