What’s the difference between a feeder, a sub-feed and a branch circuit?
The question relates to what the service from the existing house panel to a new detached garage/shop would be called..
Any other pertinent and related information would be appreated.
Replies
not an electrician
1) The last point in a feed line is a current overprotection device. A circuit breaker, or a fuse, for example. The power line coming into your house that feeds the service panel is a feed line.
2) A sub-feed would come off the main panel and feed a sub panel with overcurrent protection. So the sub feed runs between two breakers. I've seen it referred to as a "sub feed" or just a "feed".
3) A branch circuit is what comes after the circuit breaker. There is no overcurrent protection anywhere on the branch. For a branch, the overcurrent protection is at the beginning of the branch, In the service panel.
Think of it as feeders feed into circuit breaker. Branches exit the circuit breaker. A line that has protection on both ends, ie, it exits a service panel to feed a sub-panel? That is sometimes called a sub-feed.
The NEC really only defines "feeder" and "Branch Circuit". A feeder is anything between the service disconnect and the last over current device, a branch circuit is beyond the last over current device to equipment served.
"Sub-feeder" might be a feeder after a feeder but it is not defined in the NEC and there are no special rules.