how do you size service conductors for a 2 family house?

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wirenut3 said:
He did caution me to watch out for the size of my LB's if I use them, in my first call to them.
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That's a good point. Typically LB's have conductor size restrictions that are smaller than the allowable fill of the conduit.
 
infinity said:
Although you may be correct that the #4/0's are large enough without a load calc you would simply be guessing. This may or may not get past the inspector. The original poster should ask him what he requires. I've had some ask for load calc.'s or for the service entrance conductors feeding the two meter stack to be as large as the addition of the two service main OCPD's.
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Did you mean that the inspector could ask that the conductors feeding the panels have to be as large as the conductors coming down to the meters?

Wouldn't skeffibew1's use of the mains at the meterpan preclude that possibility? As they would be SER's at that point?
 
wirenut3 said:
Did you mean that the inspector could ask that the conductors feeding the panels have to be as large as the conductors coming down to the meters?

Wouldn't skeffibew1's use of the mains at the meterpan preclude that possibility? As they would be SER's at that point?
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The inspector needs to know if the conductors feeding the two meter stack are large enough to handle the connected load. One way to do this is to perform a load calculation. The other is to simply install conductors that are large enough for the worst possible case scenario which would be the total of the two loads.

For example, a fairly standard installation if you had a two family, would be a two meter stack with two 100 amp panels one for each apartment. You could simply use a set of 200 amp conductors to feed the meters and everyone is happy. Or go the longer route and perform a load calculation and maybe save some money by using smaller conductors to feed the meter stack.
 
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