Service Sizing

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peterkent

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After using Art. 220 to compute the load for a small apartment, my calculation yields 63A.
Does the NEC permit the use of a 60A service(if so, what article) or is a 100A service required?

Thanks in advance
 
230.79(C) & (D) 100 amp for a one family dwelling, for all others 60 amp
 
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peterkent said:
After using Art. 220 to compute the load for a small apartment, my calculation yields 63A.
Does the NEC permit the use of a 60A service(if so, what article) or is a 100A service required?

Thanks in advance
Click to expand...

If the calculation is 63 amps you need at least a 63 amp service.

If it where me I might check over my calculations and find a 3 amp mistake.


augie47 said:
230.79(C) & (D) 100 amp for a one family dwelling, for all others 60 amp
Click to expand...

That is the disconnecting means only, not the service size.


Usually one in the same with breakers but use a fusible switch and anything goes.:)
 
iwire said:
If the calculation is 63 amps you need at least a 63 amp service.

If it where me I might check over my calculations and find a 3 amp mistake.




That is the disconnecting means only, not the service size.


Usually one in the same with breakers but use a fusible switch and anything goes.:)
Click to expand...

If the calculated load is 63 amps, why would anyone even think about trying to get away with a 60A service?
 
If your initial computation was for 63 amps I would not try to get it any lower. While it would be code compliant if the calculated load was under 60 amps the calculation methods in the code does not give much latidude for additional loads and no one wants to see problems in the future with the work you do today.
 
iwire said:
If the calculation is 63 amps you need at least a 63 amp service.

If it where me I might check over my calculations and find a 3 amp mistake.
Click to expand...

I would not disagree that you may find a way to lose 3 amps but then again it could go the other way and I would like to say the code book is a minimum and if the calculation is 1 amp above 60 amps then I would size my service accordingly.
 
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