Generator feeder

[pete m.]

Looking for opinions.

Would the feeder from an on-site generator (702) be able to utilize table 310.15(B)(6) for sizing since the generator will be feeding the entire single family dwelling load?

It seems to me that table 310.15(B)(6) would be applicable. I can't locate anything to the contrary.

The generator does have a 100 amp breaker.

Pete

 

[chuck1727]

generator feeders

generator feeders

I believe you are correct. According to 445.13 (ampacity of conductors for generators), it is permitted to size the neutral conductor in accordance with 220.61 which talks about feeder and service neutral loads. If they are using feeder or service calculations for the neutral I think it would be safe to use 310.15(B)(6) which is also refering to feeder and service conductors for the feed.

 

[ceb58]

Is the utility service 100amp? What is the calc. load under art.220?

 

[hurk27]

The only generator I know that has a 100 amp breaker is a 20kw, if this is true then it will only produce 83.3 amps, so a #4 is fine even not using 310.15(B)(6)??? might be a problem with using SE cable with a 60? rating?

 

[pete m.]

Is the utility service 100amp? What is the calc. load under art.220?

The service is 200 amp. The load the generator is feeding is well under the 20kw output via a 125 amp transfer device located in the service panel.

Pete

 

[iwire]

The service is 200 amp. The load the generator is feeding is well under the 20kw output via a 125 amp transfer device located in the service panel.

Pete

In that case there is no question that you cannot use 310.15(B)(6).

To use table 310.15(B)(6) the feeder would have to carry the entire load of the house.

 

[ceb58]

In that case there is no question that you cannot use 310.15(B)(6).

To use table 310.15(B)(6) the feeder would have to carry the entire load of the house.

Agree with Bob, you cannot use the table. Your wire must be sized to the OCP which would be the 100amp on the gen.