Double feeders

[hhsting]

Attached sketch meter stack has 2000A main breaker and 250A feeder breaker from meter stack feed two feeders as shown. One going to 100A disco and another going to second 100A disco. Feeder size is 3#350 + 4GRD.

Question:
1. If meter stack is inside building then I see no reason why two feeders cannot be from same feeder breaker. It’s not a tap but splice no tap rules. Am I correct or incorrect?

2. If meter stack is outside the building then I am not sure if I can have two feeders going into building. What are your thoughts?

 

[winnie]

1) Think about multiple breakers tapped off of a bus duct. You have a 'backbone' circuit supplied by a breaker, and then multiple breakers tapped off of this backbone. That is exactly what you have with two sets of wire fully protected at their ampacity by the supply breaker.

2) In general you can only have one service or feeder to a building (note there are a pile of exceptions) and at a building you need a single 'disconnect'. But....simply being outside does not mean the meter stack is a separate building; is the meter stack itself the 'disconnect' for the building? If you connect your runs of 350 kcmil together to form parallel conductors, then you make them into a single feeder.

3) When the circuit conductors are increased in size versus the minimum size for the circuit OCPD, you also have to increase the size of the EGC. I think the #4 GRD is too small.

-Jon

 

[Dennis Alwon]

If you have meters attached to the building then you can enter that same building with as many feeders as you want

 

[Dennis Alwon]

When the meters are detached from the building is when you have a problem.

 

[electrofelon]

Just curious do you know why the 350's are so large? Is it a long run? Prolly going to need to reduce that to land on a 100A disco.

 

[hhsting]

Just curious do you know why the 350's are so large? Is it a long run? Prolly going to need to reduce that to land on a 100A disco.

Correct primary disconnect is 1450 feet away from meter stack. Boy you all are sharp first post also pointed out to upsize EGC. I thank all of your input.

However I just found out that the circuit breaker lug in meter stack is only rated for one set of 350 kcmil not two sets 350 kcmil.

I would imagine this would be violation of NEC 2014 section 110.3(b). What do you think?

 

[electrofelon]

However I just found out that the circuit breaker lug in meter stack is only rated for one set of 350 kcmil not two sets 350 kcmil.

I would imagine this would be violation of NEC 2014 section 110.3(b). What do you think?

Well if you somehow were able to jam 2 350's into a lug made for 1 350, then yes that would be a code violation, but on the other hand you could prolly make a million dollars making a YouTube video on how you did it. . You will have to transition from one conductor to two using an appropriate connector.