Does the code defy it's own definition of the word feeder?

J

jes25

Senior Member
Location
Midwest
Occupation
Electrician
I present to you an excerpt 695.6(A)(2):

(2) Feeders.
Fire pump supply conductors on the load side of the final disconnecting means and overcurrent device(s) permitted by 695.4(B) or conductors that connect directly to an on-site standby generator shall comply with.........

My question is, by definition how can conductors on the load side of the final disconnecting means and overcurrent device(s) be a Feeder as the heading indicates?
 
Because they are on the line side of the fire pump controller and the conductors from the fire pump controller to the fire pump motor will be the motor branch circuit conductors.
 
don_resqcapt19 said:
Because they are on the line side of the fire pump controller and the conductors from the fire pump controller to the fire pump motor will be the motor branch circuit conductors.
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Fair enough and thanks for the reply. I assume that fire pump controller always has an OCPD in it for that to work with the definitions?

After carefully rereading the entire paragraph together, I think I get it but "feeder" and "load side of the final disconnecting means and overcurrent device" don't go together at first look.
 
I tried to get the definition to make an exception when the feeder is connected to a single piece of equipment. For instance, the wire run for an ac unit from a panel to a fused disconnect is a feeder and the branch circuit is the conduction from the disconnect to the ac. However, if the disconnect is unfused then the entire run is a branch circuit. It makes a difference in some cases.

When I spoke with a code panel member he said he would treat the entire run as a branch circuit regardless of it having overcurrent protective device or not.

If that what he believes then why not make the exception. It is one area that is lacking in my opinion.

I realize the original poster's question was not about ac units.
 
Dennis Alwon said:
I tried to get the definition to make an exception when the feeder is connected to a single piece of equipment. For instance, the wire run for an ac unit from a panel to a fused disconnect is a feeder and the branch circuit is the conduction from the disconnect to the ac. However, if the disconnect is unfused then the entire run is a branch circuit. It makes a difference in some cases.
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Oh, can you give a case where it does make a difference? I'm not aware of any.

Cheers, Wayne
 
Dennis Alwon said:
Yeah, I used to have one but as usual my old brain can't recall right now. I believe it had something to do with motors.
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Pretty sure that it is a common misconception, I'm not aware of any allowance for a branch circuit supplying just one motor than isn't also present for a feeder supplying just one motor.

Cheers, Wayne
 
Running a feeder to an ac unit and having disconnects would allow the required receptacle to be fed from the feeder. Running an ac branch circuit would not allow the receptacle to be supplied from the ac branch circuit
 
wwhitney said:
Oh, can you give a case where it does make a difference? I'm not aware of any.

Cheers, Wayne
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Suppose I had a Fire Pump Controller without OCPD in it and I said the wires feeding it were by definition branch circuits. Then, suppose I said 695.6(A)(2) doesn't apply because it's under the heading "Feeders" and as such I don't need to encase the raceway in concrete. Now that makes a big difference.

That was essentially the root of my initial question.
 
Eddie702 said:
Running a feeder to an ac unit and having disconnects would allow the required receptacle to be fed from the feeder. Running an ac branch circuit would not allow the receptacle to be supplied from the ac branch circuit
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Well, that example is outside of my comparison of a branch circuit supplying only one motor (or piece of HVAC equipment) vs a feeder supplying the same. The receptacle is a second load. Dennis's proposed change would not have applied to the feeder supplying both the disconnect and the receptacle.

But as to your comparison, say the MOCP is 20A or less, and the MCA is maybe 12A or less. Is there any prohibition on using a 20A breaker supplying #12 conductors which supply both the receptacle and the A/C disconnect? The disconnect would have smaller fuses if the MOCP is below 20A. The #12 conductors would be a branch circuit with respect to the receptacle and, if the disconnect is fused, a feeder with respect to the A/C.

Cheers, Wayne
 
@wwhitney As far as I know a feeder can have a reduced neutral but a branch circuit cannot except for ranges and dryers. So I could potentially run a smaller neutral to a piece of equipment as a feeder but then would have to upsize the neutral from the disconnect to the equipment. Am I wrong there?
 
Dennis Alwon said:
@wwhitney As far as I know a feeder can have a reduced neutral but a branch circuit cannot except for ranges and dryers. So I could potentially run a smaller neutral to a piece of equipment as a feeder but then would have to upsize the neutral from the disconnect to the equipment. Am I wrong there?
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No, that's a good example, thank you. Although I'm not sure what type of real world equipment would require an MWBC and would also list its L-L (or L-L-L) load separately from its L-N load.

This example, though, is one where it is advantageous to consider the conductors to be a feeder rather than a branch circuit. Your proposal would only have been beneficial if you have a case where it is advantageous to consider the conductors to be a branch circuit rather than a feeder. Do you have any examples of that scenario?

Cheers, Wayne
 
wwhitney said:
Before I consider your question, does such a thing exist? Don seemed to suggest it does not.

Cheers, Wayne
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Not sure on that. If anyone does a lot of fire pumps I'd be interested to know if they exist without OCPD in them. Mu suspicion is that they do exist and may even be common.....but I'm speculating.
 
wwhitney said:
No, that's a good example, thank you. Although I'm not sure what type of real world equipment would require an MWBC and would also list its L-L (or L-L-L) load separately from its L-N load.

This example, though, is one where it is advantageous to consider the conductors to be a feeder rather than a branch circuit. Your proposal would only have been beneficial if you have a case where it is advantageous to consider the conductors to be a branch circuit rather than a feeder. Do you have any examples of that scenario?

Cheers, Wayne
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Of course not....haha I figured someone might somewhere in this crazy electrical world.
 
wwhitney said:
No, that's a good example, thank you. Although I'm not sure what type of real world equipment would require an MWBC and would also list its L-L (or L-L-L) load separately from its L-N load.

This example, though, is one where it is advantageous to consider the conductors to be a feeder rather than a branch circuit. Your proposal would only have been beneficial if you have a case where it is advantageous to consider the conductors to be a branch circuit rather than a feeder. Do you have any examples of that scenario?

Cheers, Wayne
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What about an outside hot tub that needs a neutral? That may be an example
 
wwhitney said:
Well, that example is outside of my comparison of a branch circuit supplying only one motor (or piece of HVAC equipment) vs a feeder supplying the same. The receptacle is a second load. Dennis's proposed change would not have applied to the feeder supplying both the disconnect and the receptacle.

But as to your comparison, say the MOCP is 20A or less, and the MCA is maybe 12A or less. Is there any prohibition on using a 20A breaker supplying #12 conductors which supply both the receptacle and the A/C disconnect? The disconnect would have smaller fuses if the MOCP is below 20A. The #12 conductors would be a branch circuit with respect to the receptacle and, if the disconnect is fused, a feeder with respect to the A/C.

Cheers, Wayne
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Well now that I think about it most newer condensing furnaces require a 120 volt circuit for the furnace and a condensate pump is usually allowed to be on the same circuit whether hard wired or plugged in to a receptacle. But that is related equipment. But on a outdoor condensing unit the receptacle is required for servicing the equipment not for related equipment.

The purpose as we all know is to discourage the use of cheater cords to run vacuum pumps and other related service equipment.

I started in 73' and worked on a lot of roof top equipment and it was a real PITA because there were no roof top receptacles back then and you would have to string 100s of feet of cord or use a cheater cord. On 480 volt you were screwed. I can remember using a small transformer a few times.

Finally the code required receptacles first it was 75', then 50', the 25' which I think is a little crazy. Everyone has a 50' extension cord and I think 50' is reasonable JMHO
 
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