what defines a FEEDER from BRANCH CIRCUIT

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Tom said
...was a feeder then it would require a grounding electrode system, if it was outside the building...
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This is not true unless it is a feeder to a seperate structure.

A fused A/C disconnect mounted outside of a building, does not require a grounding electrode system. Even given the NEC's loose interpretation of structure I can not rationalize calling an appliance a structure especially because 440.3(B) doesn't.
 
jim dungar said:
Tom said This is not true unless it is a feeder to a seperate structure.

A fused A/C disconnect mounted outside of a building, does not require a grounding electrode system. Even given the NEC's loose interpretation of structure I can not rationalize calling an appliance a structure especially because 440.3(B) doesn't.
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Jim if it's built or constructed it is struture.

The NEC considers lightpoles and sign posts structures, if a simple pole is a structure than IMO a remotely located HVAC unit must be as well.
 
If we are talking about an HVAC unit sitting beside the building, with line sets and electrical tethering it, serving the building, then I would not call it an independent structure. A disconnect (or panel) would usually be mounted on the served building, not on the HVAC unit.
 
iwire said:
Jim if it's built or constructed it is struture.

The NEC considers lightpoles and sign posts structures, if a simple pole is a structure than IMO a remotely located HVAC unit must be as well.
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So in your opinion are all hot tubs/spas, water fountains structures?

How about outdoor vending machines? What about the dryer on my back deck?

Am I violating the NEC every time I use my electric hedge trimmers that are fed by an extension cord?
 
Jim,
Most of those are "structures" per the NEC definition of that word. As I told Bob in an earlier post, we have to use the code language, and not the real world language. Most of those structures are not served by feeders, but by a single branch circuit and would not require a grounding electrode system.
Don
 
Don, you say most of my items are structures.

Please be specific which are and which aren't.

If the A/C unit is fed by a single circuit then wouldn't it also not need a ground electrode system.
 
I do not see the disconnect with overcurrent protection located outside the building that supplies the A/C unit as supplementary protection. The disconnect can be a pullout or a nonfused disconnect. The installation from the disconnect to the A/C unit is field installed and is not installed as per supplementary overcurrent considerations.
There is a feeder to the disconnect, than a branch circuit from the fused disconnect to the A/C unit.


An appliance is not that which is built, it is that which is manufactured.
 
Jim,
I don't see the cord and plug connected equipment as structures.
If the A/C unit is fed by a single circuit then wouldn't it also not need a ground electrode system.
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If it is fed by single branch circuit there is no requirement for a grounding electrode. Note, I am not saying that anyone installs grounding electrodes for things like this, just that the code wording can be read to require it.
Don
 
Pierre,
I do not see the disconnect with overcurrent protection located outside the building that supplies the A/C unit as supplementary protection. The disconnect can be a pullout or a nonfused disconnect. The installation from the disconnect to the A/C unit is field installed and is not installed as per supplementary overcurrent considerations. There is a feeder to the disconnect, than a branch circuit from the fused disconnect to the A/C unit.
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I agree that the fuses at the AC disconnect are not supplementary protection. I don't agree that the fused disconnect is installed to protect the supply side conductors to the disconnect, and I don't agree that the addition of the fused disconnect changes the line side conductors from branch circuit conductors to feeder conductors.
Don
 
Again, I am lost. I have read the replies, and don't know where people stand.

If the code description of a Branch Circuit and a Feeder are as follows:

Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).

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.

...then how do you guys come up with the things you say?

If a FUSED disconnect (non fused is a different story) is placed at the equipment, that is the 'final branch circuit overcurrent device'. Am I wrong? Are fuses overcurrent protection? Are they not located in a Branch Circuit? And are they not at the end, or 'final' for the circuit? Just because the fuses may not be THE OCPD, but it is still A OCPD.


I also believe that the Fuses located in the disconnect DO protect the line side conductors. The line side conductors will never see more current than the fuses allow. Unless they are tapped conductors, but then another code covers taps, and even then the taps that feed the disconnect will never see more than the fuses allow.
 
by Don
In many cases, if the conductors are feeders, they would have to be two sizes larger than if they are branch circuit conductors.
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Don, can you explain this statement please? I am not saying you are right or wrong, I am just curious to the statement. I don't know if you base this off a code rule or calculations or experience, because I am unsure.
Again, not labelling this as right OR wrong, I just would like a little more to back this statement, because I am having trouble finding it.

Thank you
 
I think the way to asnwer the feeder -vs- branch circuit issue is:

Would the wires be adequately protected if a non fused disconnect was used downstream? If so, its a branch circuit.

The reason a fuse is added would be because the item said fuses and not an HACR breaker. Article 440 allows any hermetic air conditioner can have overcurrent larger than the wire (up to the code limited percentage over) because the thermal cutout in the compressor helps to protect the wires.

In the case of a hot tub it is similar, you may have the correct size circuit, but it is not GFCI. A GFCI doesn't protect wires, but protects people. Putting a GFCI breaker based disconnect in line with this circuit shouldn't change it to a feeder. This is important because pool and spa feeders requires special wiring methods (insulated grounds, and conduit) whereas branch circuits aren't as restrictive.

The rules allowing an HVAC branch circuit to have a breaker larger than the wire ampacity only applies to branch circuits and not feeders. So again, it is important to determine if this is a feeder or a branch circuit in HVAC circuits. It seems kind of silly that this is the case, but it becomes less silly if you realize that putting a breaker on the end with different characteristics doesn't change things much.

I must admit though, that I don't know if a circuit using a circuit breaker is adequately protected if the HVAC appliance says fuses only. Is that fused disconnect added at the end protecting the wires, or the HVAC unit? If the breaker was the normal size for the installed wire, I'd say of course. But HVAC circuits typically are breaker over the normal 310.16 ampacity, so now I'm not sure (depends on the HVAC thermal cutout characteristics). If you installed an HVAC unit that allowed breakers and you used a disconnect with a breaker, then this is a branch circuit.
 
Steve,
If they are feeders the conductors have to be sized per the feeder OCPD. If they are branch circuit conductors the rating of the branch circuit OCPD can be greater than the rating of the branch circuit conductors. The rules that permit this only apply to branch circuits...not to feeders. If the nameplate says minimum circuit ampacity of 25 amps and maximum OCPD of 40 amps, if the circuit is a branch circuit, you can use #12 on a 40 amp breaker...if the circuit is a feeder you need #8 wire on that same 40 amp breaker.
Don
 
Now it's clear: if the wire is smaller than normally allowed on a certain breaker, then it must be a branch circuit.
 
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