Feeder or branch circuit

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RampyElectric

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Location
Liberty SC
OK.... 4 wires run to a sub panel.....2 hots 1 neutral 1 ground.....is it a branch circuit or a feeder. The sub panel supplies 2or more branch circuits.

In one state I failed inspection because I installed it as a branch, now in SC Im being told I have to reduce the breaker size because its a branch circuit

Is Mr Holland in the house?
 
C

cpal

Senior Member
Location
MA
this should be pretty "cut and dry" per the definitions in art 100

It sounds as if your feeder 2 hots a neut (grounded) and EGC is a Feeder

between the service eq and the final ocpd (branch circuit)
 
roger

roger

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Location
Fl
Occupation
Retired Electrician
Rampy, as Charlie points out, your answer is in the definitions and has nothing to do with OCPD size.

If I run conductors from a 200 amp breaker to a 200 amp fused disconnect it is a feeder.

When I run 200 amp conductors from the 200 amp fused disconnect above to an outlet it is a branch circuit.

Roger
 
charlie b

charlie b

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Location
Lockport, IL
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Retired Electrical Engineer
Here's a simple (if not precisely correct in all aspects, but still good enough for everyday use) way to look at it. Start at the final load, and look back along the wires. As soon as you seen an overcurrent device, you know that that wire you just followed upstream is a branch circuit wire. From that overcurrent device further upstream, everything is a feeder, until you get to the supplying utility.
 
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cpal

Senior Member
Location
MA
this should be pretty "cut and dry" per the definitions in art 100

It sounds as if your feeder 2 hots a neut (grounded) and EGC is a Feeder

between the service eq and the final ocpd (branch circuit)
 
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cpal

Senior Member
Location
MA
Sorry for the double post

Rampy in or area if the inspector is unclear verbally we can request the violation in writing.

if you have that option it may give you a code article to start from
 
roger

roger

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Location
Fl
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What was the size of the conductors?

Roger
 
1793

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
Conductor size...

Conductor size...

RampyElectric said:
He wouldnt let me use a 100amp breaker....he said it had to be 85.....WHAT?!
Click to expand...

Could the Inspector be questioning the size of the conductors used between the two panels?
 
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jeff43222

Senior Member
Location
Minneapolis, Minnesota
RampyElectric said:
Thats exactly what I said, so the inspector said I should look a few pages before 310.16 and I would find the answer? What the heck is he talkin about!?
Click to expand...
My guess is he's talking about T310.15(B)(6), which covers ampacities for service feeders. We covered this in a previous thread, and I think the consensus was that if the feeder was the main power to a dwelling unit, T310.15(B)(6) applied, but if the feeder was (for example) from a house's main panel to the subpanel in the detached garage, then you can't use T310.15(B)(6).

Given the numbers you are talking about, my guess is you used #4 Cu for a feeder to a subpanel and thought T310.15(B)(6) allowed a 100A breaker to protect it, but the inspector probably said that the feeder in question wasn't a service feeder, so T310.16 limits you to an 85A breaker.
 
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jeff43222

Senior Member
Location
Minneapolis, Minnesota
I considered the possibility of #2 Al, but I noticed the ampacity for it was a bit different than for #4 Cu in T310.16. When he mentioned the inspector said 85A, I figured he was using #4 Cu since that's the exact value in the table.
 
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