AmpsOverVolts
Member
- Location
- California
- Occupation
- Electrician
I am installing PV arrays that all feed to switchgear that then lands on the supply-side of the MSB.
According to 705.28(C)(2) the neutral used for instrumentation can be sized according to 250.102 (no longer the EGC).
So according to this if I have a 6 parallel runs of 500kcmil than my neutral should be:
6x500000=3000000x.125=375000 which equals a 400kcmil.
However my question has to do with if each run of the parallel is going to need a 400kcmil or can i parallel this so that 375000/6 = 625000 which would equal a #2?
now what is throwing me off is according to 2.15.2(A)(2) for feeders the grounded conductor will not be smaller than 250.122, but for neutrals we can also size according to calculated load for a smaller neutral 220.61 ( though I don't have that so i am going for a minimum sizing). Also if I follow 705.11(B) leads to 230.30 to 250.24(C) which says that each raceway essential will be treated separately when calculating for the grounded conductors in parallel which would mean according to 250.102 I would need a 1/0?
so do I need a 400kcmil? a #2? or a 1/0?
i referenced this for some of my thought process:
www.electricalcodeacademy.net
According to 705.28(C)(2) the neutral used for instrumentation can be sized according to 250.102 (no longer the EGC).
So according to this if I have a 6 parallel runs of 500kcmil than my neutral should be:
6x500000=3000000x.125=375000 which equals a 400kcmil.
However my question has to do with if each run of the parallel is going to need a 400kcmil or can i parallel this so that 375000/6 = 625000 which would equal a #2?
now what is throwing me off is according to 2.15.2(A)(2) for feeders the grounded conductor will not be smaller than 250.122, but for neutrals we can also size according to calculated load for a smaller neutral 220.61 ( though I don't have that so i am going for a minimum sizing). Also if I follow 705.11(B) leads to 230.30 to 250.24(C) which says that each raceway essential will be treated separately when calculating for the grounded conductors in parallel which would mean according to 250.102 I would need a 1/0?
so do I need a 400kcmil? a #2? or a 1/0?
i referenced this for some of my thought process:
Sizing Neutrals (Grounded) in a Parallel Service Explained
We are often obsessed with electrical calculations that seem to say one thing but end up meaning something else altogether. One example of this may appear when sizing the grounded (neutral) conductor on a service with parallel ungrounded conductors.In this article, we will examine the thought...
www.electricalcodeacademy.net