Sub Panel conductors - Feeders or branch circuit conductors

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csoc64

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Feeding a 60A garage sub-panel (main lug panel). 60A breaker is located in the 200A main breaker panel. Are the conductors feeding the MLO sub-panel from the load side of the 60A breaker considered feeders or branch circuit conductors? Feeder - "All circuit conductors between the service equipment...and the final branch-circuit overcurrent device". Here, there is no "final branch-circuit overcurrent device" because I am feeding a MLO panel. Would I need to supply a 60A breaker in the garage sub-panel and feed that breaker for this definition to apply? Branch Circuit - "The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s)." Is the MLO panel considered an "outlet" supplying "utilization equipment"?
 

Dennis Alwon

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Chapel Hill, NC
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Retired Electrical Contractor
Is the garage attached or detached?

No main necessary if it is attached and if detached you either need a main or use the 6 disconnect rule. The conductors to the sub panel is a feeder since there is overcurrent protective device after the conductors. The wires from the final overcurrent protective device are the branch circuits
 

csoc64

Senior Member
Location
northeast
Is the garage attached or detached?

No main necessary if it is attached and if detached you either need a main or use the 6 disconnect rule. The conductors to the sub panel is a feeder since there is overcurrent protective device after the conductors. The wires from the final overcurrent protective device are the branch circuits
Garage is detached. So if I use a main at the sub panel, does that now make the conductors branch circuit conductors?
 

augie47

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State Electrical Inspector (Retired)
Branch Ckt.jpg

As stated, a branch circuit refers to conductors after the final over-current device
 

ActionDave

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Durango, CO, 10 h 20 min from the winged horses.
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Feeding a 60A garage sub-panel (main lug panel). 60A breaker is located in the 200A main breaker panel. Are the conductors feeding the MLO sub-panel from the load side of the 60A breaker considered feeders or branch circuit conductors? Feeder - "All circuit conductors between the service equipment...and the final branch-circuit overcurrent device". Here, there is no "final branch-circuit overcurrent device" because I am feeding a MLO panel.....
Feeders go to your MLO panel. The branch circuits start after the individual branch circuits breakers in your MLO panel.
 

csoc64

Senior Member
Location
northeast
Feeders go to your MLO panel. The branch circuits start after the individual branch circuits breakers in your MLO panel.
OK. Got it. Next question. I am feeding with SER, which will be run exposed through a basement and garage and will not be installed in any thermal insulation. Am I correct that I can use values from 75C column from 310.15(B)(16) (due to terminal ratings of 75C) and feed this with #4 aluminum SER?
 

augie47

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Tennessee
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State Electrical Inspector (Retired)
OK. Got it. Next question. I am feeding with SER, which will be run exposed through a basement and garage and will not be installed in any thermal insulation. Am I correct that I can use values from 75C column from 310.15(B)(16) (due to terminal ratings of 75C) and feed this with #4 aluminum SER?

#4 Al should be fine. Does your feeder go underground to the detached garage ?
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
Yes, but I transition (in the existing garage) to #6 THHN copper to feed the new garage through underground PVC raceway.


Sounds good to go. Remember at the garage you will also need 2 ground rods or one of the other electrodes mentioned in art. 250
 
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