Clarification on "branch circuit" and "feeder" with regards to 2011 ed. 250.32(A)

[MRKN]

Clarification on "branch circuit" and "feeder" with regards to 2011 ed. 250.32(A)

Hi,

Per Exhibit 250.18, referenced in the 2011 ed. 250.32(A) Exception item (shown attached), I am a little confused as to the use of the word "branch circuit". It seems to be that by definition, if you are using a branch circuit to supply a sub panel, or any OCPD as shown in the Exhibit, it is no longer a branch circuit, but a feeder.

Please advise.

 

[Smart $]

... if you are using a branch circuit to supply a sub panel, or any OCPD as shown in the Exhibit, it is no longer a branch circuit, but a feeder.

Please advise.

Correct. By definition a branch circuit originates at the last overcurrent protection device (ocpd), excluding supplementary ocpd.

Any conductor between the branch circuit ocpd and service disconnect is a feeder or feeder tap.

 

[m sleem]

It is a feeder or circuit not a branch circuit.

 

[MRKN]

I am with you guys. As shown in Exhibit 250.18 from the 2011 NEC Handbook (my attached picture from the original post), it appears there is a 2nd breaker in the remote building's sub panel. The commentary following the exception provides this exhibit as an example of the exception to 250.32(A):

"Exception: A grounding electrode shall not be required
where only a single branch circuit, including a multiwire
branch circuit, supplies the building or structure and the
branch circuit includes an equipment grounding conductor
for grounding the normally non?current-carrying metal
parts of equipment."

Hence the source of my confusion.

 

[david luchini]

I am with you guys. To be specific then (Exhibit 250.18 from the 2011 NEC Handbook), as shown in my attached picture from the original post, it appears there is a 2nd breaker in the remote building's sub panel. Hence the source of my confusion.

I don't think they intend to show an overcurrent device at the remote building, just a disconnecting means.

 

[MRKN]

I don't think they intend to show an overcurrent device at the remote building, just a disconnecting means.

That would explain it. I am not used to seeing that symbol used for anything other than a breaker.

 

[Smart $]

That would explain it. I am not used to seeing that symbol used for anything other than a breaker.

Agree. Depicts a circuit breaker... not a switch.

 

[GoldDigger]

I don't think they intend to show an overcurrent device at the remote building, just a disconnecting means.

The person who wrote the commentary may not have been thinking that an in-line OCPD, not supplying anything but the one circuit, really became the demarcation between a feeder and a branch circuit.
Or possibly the OCPD at the disconnect is just a supplementary OCPD rather than one which meets NEC requirements to be a branch circuit protective device?

How much further can we twist the logic on this, I wonder?

Definitely something worth thinking about. A multi-breaker panel at the remote end would certainly make it a feeder.

 

[jwelectric]

Look real close and see if it is not a two wire circuit with an equipment grounding conductor that is connected to the enclosure.

The breaker is nothing more than the 225.31 requirement that fulfills the requirement of 225.39 (A) although the exception to 225.36 will allow for a single pole, a set of three or four way switches the breaker would not constitute a feeder.

 

[MRKN]

Look real close and see if it is not a two wire circuit with an equipment grounding conductor that is connected to the enclosure.

The breaker is nothing more than the 225.31 requirement that fulfills the requirement of 225.39 (A) although the exception to 225.36 will allow for a single pole, a set of three or four way switches the breaker would not constitute a feeder.

I agree with you, yet there does still seem to be a contradiction with the strict definition of branch circuit and feeder provided in the NEC. However, I think this is where engineering judgement comes into play.
Since it's only a diagram it's nothing that important, just got me thinking.

 

[jim dungar]

I am not used to seeing that symbol used for anything other than a breaker.

We use that symbol for molded case circuit breakers and molded case switches to differentiate them from 'open blade' switches.

 

[fmtjfw]

This is the problem with using the Handbook. The pictures don't cover all the instances and in some case, I believe, are just plain wrong. End of Rant:rant: