Hi,
I have been searching around to get an explanation why this is an issue with some inspectors wheres others have another opinion on where the branch circuit begins from the perspective of NEC and UL508A panels. :dunce:
The problem is when it comes to having several branch circuits breakers in series. Some inspectors point out that the branch circuits begins after the last branch circuit breaker due to the code says so.
I do not understand why it is an issue to not begin at the first branch circuit breaker. There the branch begins and all circuit breakers after this branch circuit breaker is just additional protection for specific circuits within its branch.
I have been speaking to two guys at UL and also been in contact with Intertek. As I understands it is an issue if you strict go by the wording in the code/standard.
NFPA 70:
Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent
device.
Why do I want to have two branch circuit breakers in-line.
To get as quick as possible the branch circuit spacing per distances in UL508A §10.
To protect the EMI filter for the panel.
Power switch -> CB1 -> EMI -> CB(x) -> Motor controller
After EMI filter there can be several CB's for several motor controllers.
How do you build your panels to follow the feeder description in NFPA 70 or NFPA79?
I have been searching around to get an explanation why this is an issue with some inspectors wheres others have another opinion on where the branch circuit begins from the perspective of NEC and UL508A panels. :dunce:
The problem is when it comes to having several branch circuits breakers in series. Some inspectors point out that the branch circuits begins after the last branch circuit breaker due to the code says so.
I do not understand why it is an issue to not begin at the first branch circuit breaker. There the branch begins and all circuit breakers after this branch circuit breaker is just additional protection for specific circuits within its branch.
I have been speaking to two guys at UL and also been in contact with Intertek. As I understands it is an issue if you strict go by the wording in the code/standard.
NFPA 70:
Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent
device.
Why do I want to have two branch circuit breakers in-line.
To get as quick as possible the branch circuit spacing per distances in UL508A §10.
To protect the EMI filter for the panel.
Power switch -> CB1 -> EMI -> CB(x) -> Motor controller
After EMI filter there can be several CB's for several motor controllers.
How do you build your panels to follow the feeder description in NFPA 70 or NFPA79?