Size of service conductors

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dce

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You have a two gang meter for two 100 amp services; it has a #2 seu cable running from the meter up to the point of attactment; it has to be replaced; so can I replace it with the same size or what?
I do realize it has been like that but was it right in the first place. 230.42 (A) says the service entrance conductors can be sized for the sum of the noncontinuous load plus 125% of the continuous load. But 230.42 (B) says that in addition to part 230.42 (A) The minumum ampacity of the ungrounded conductors shall not be less than the rating of the service disconnecting means. My thoughts are as long as the conductors from the meter up were sized to carry the total load of the service and the conductors from the meters to the service panels were sized to that unit load and were sized to the service disconnecting means it is correct. Am I over looking something?

Thanks
 
T. 310.15(B)(6) can be used to size 3 wire 1Ph service conductors for two family dwells.


Are you inspecting this, or doing the work?
 
dce said:
You have a two gang meter for two 100 amp services; it has a #2 seu cable running from the meter up to the point of attactment; it has to be replaced; so can I replace it with the same size or what?
I do realize it has been like that but was it right in the first place. 230.42 (A) says the service entrance conductors can be sized for the sum of the noncontinuous load plus 125% of the continuous load. But 230.42 (B) says that in addition to part 230.42 (A) The minumum ampacity of the ungrounded conductors shall not be less than the rating of the service disconnecting means. My thoughts are as long as the conductors from the meter up were sized to carry the total load of the service and the conductors from the meters to the service panels were sized to that unit load and were sized to the service disconnecting means it is correct. Am I over looking something?

Thanks
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You didn't read through the end of 230.42(B)

(B) Specific Installations. In addition to the requirements
of 230.42(A), the minimum ampacity for ungrounded conductors
for specific installations shall not be less than the
rating of the service disconnecting means specified in
230.79(A) through (D).

It says the ampacity can't be less the the rating of disconnects specified in 230.79(A) through (D).


230.79 Rating of Service Disconnecting Means. The service
disconnecting means shall have a rating not less than
the calculated load to be carried, determined in accordance
with Part III, IV, or V of Article 220, as applicable. In no
case shall the rating be lower than specified in 230.79(A),
(B), (C), or (D).
(A) One-Circuit Installations. For installations to supply
only limited loads of a single branch circuit, the service
disconnecting means shall have a rating of not less than 15
amperes.
(B) Two-Circuit Installations. For installations consisting
of not more than two 2-wire branch circuits, the service
disconnecting means shall have a rating of not less than 30
amperes.
(C) One-Family Dwellings. For a one-family dwelling,
the service disconnecting means shall have a rating of not
less than 100 amperes, 3-wire.
(D) All Others. For all other installations, the service disconnecting
means shall have a rating of not less than 60
amperes.
 
I see, It is correct then as long as conductors from the meters up to the service drop are sized for the load of both units. I thought it was but I read part (B) and like you are saying I did not read it completely. Then I starting questioning myself.

Thanks,
 
Yes I will be inspecting it, I think I am correct in this but when I read part (B) I did not read it completely and then questioned myself.

Thanks
 
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