GFCI, AFCI for Furnace

[kwired]

A furnace would be an outlet, correct?

Furnace itself is not an outlet, there is an outlet somewhere in the application though. exact location maybe a little debatable but at some point you do have wiring that is part of the utilization equipment and wiring that is part of the branch circuit. Wherever the dividing line is between those two is the outlet location.

 

[mbrooke]

No, it merely receives its power from one. The outlet for a hard-wired furnace would be either the J-box where the wiring emerges from the wall (if there is one) or the end of the wiring that enter's the furnace's wiring compartment.

Would code allow wiring into the furnace, to a side mounted switch and then to the hook up wires? I know that probably the dumbest thing ever said on this forum, but my brain is doing gymnastics around the AFCI requirements.

 

[mbrooke]

Furnace itself is not an outlet, there is an outlet somewhere in the application though. exact location maybe a little debatable but at some point you do have wiring that is part of the utilization equipment and wiring that is part of the branch circuit. Wherever the dividing line is between those two is the outlet location.

I'd say so.

 

[Dennis Alwon]

Would code allow wiring into the furnace, to a side mounted switch and then to the hook up wires? I know that probably the dumbest thing ever said on this forum, but my brain is doing gymnastics around the AFCI requirements.

You can do whatever you want but the fact is the circuit will need an afci.

 

[al hildenbrand]

Would code allow wiring into the furnace, to a side mounted switch and then to the hook up wires? I know that probably the dumbest thing ever said on this forum, but my brain is doing gymnastics around the AFCI requirements.

Pay close attention to the use of the Article 100 term "device" in 2017 NEC 210.12(A). . . . "outlet or device" . . . FYI, up here in the cold north, putting a plain old snap switch in a box on the side of the furnace is the way it is done.

 

[augie47]

I posed the question based on an actual inspection where the appliance was fed directly from the panel. The discussion made it to a CMP member. His answer is obviously still just an opinion but a bi more valuable than mine as he is involved in the writing of the Code.
His opinion is that AFCI would not be required as, again his opinion, there is no "outlet". He feels it is a Code oversight and 210-.12 will eventually have "utilization equipment" added to" "outlets and devices". I posted it to provoke thought and realize opinions and enforcement will vary.

 

[mbrooke]

You can do whatever you want but the fact is the circuit will need an afci.

Hoping there was a loop hole somewhere in the code.

 

[al hildenbrand]

His opinion is that AFCI would not be required as, again his opinion, there is no "outlet". He feels it is a Code oversight and 210-.12 will eventually have "utilization equipment" added to" "outlets and devices".

"there is no outlet."

Wow. Just wow.

:jawdrop:

 

[goldstar]

Aside from all the NEC Bible discussion about this, who among you (and let's have a show of hands) would want an AFCI protected circuit on their furnace during a winter snow storm when it's about 6 degrees outside ? Code requirement or not, this is a bad idea IMHO.

 

[ptonsparky]

Aside from all the NEC Bible discussion about this, who among you (and let's have a show of hands) would want an AFCI protected circuit on their furnace during a winter snow storm when it's about 6 degrees outside ? Code requirement or not, this is a bad idea IMHO.

Given the assumption that AFCIs do work, who would rather it trip during a winter storm, or suffer the resulting fire without one?

 

[StarCat]

Goldstar, I am glad someone is being REAL about this.
In Sincerity

Star

 

[Dennis Alwon]

Aside from all the NEC Bible discussion about this, who among you (and let's have a show of hands) would want an AFCI protected circuit on their furnace during a winter snow storm when it's about 6 degrees outside ? Code requirement or not, this is a bad idea IMHO.

This is the same argument we heard about gfci on refrigerators. I admit it does appear to be overdone and I would love to know what the statistics are for furnaces causing fires and would an afci have helped.

 

[kwired]

Given the assumption that AFCIs do work, who would rather it trip during a winter storm, or suffer the resulting fire without one?

Given the assumption that AFCI's do work, isn't one of main reasons it is required to protect the entire branch circuit because of vulnerabilities in NM cable? After all they have allowed metallic wiring methods then AFCI at first outlet.

If reasoning is because of vulnerability of NM cable then why not AFCI requirement for all NM cable regardless of circuit voltage/current rating?

Also in the furnace application, about the only thing that is much risk for electrical fire (presuming good installation and maintenance) is more likely in the supply circuit, the furnace itself would probably contain anything that occurred within.

If anything this is another case where it would likely contain anything long enough for GFPE to catch it once it starts producing fault current.

I don't believe such an appliance is all that likely to start a fire as a result of arcing, not that arcing can't occur, but will likely be contained enough it won't spread before it either develops a ground fault and trips OCPD or burns itself out. At 120 volts to ground it probably burns itself out most cases.

I have seen 277 volts to ground continue to arc many times, can't recall ever seeing 120 to ground not clearing itself, yet they push the code to use these products on 120 volt circuits:ashamed:

 

[ptonsparky]

Given the assumption that AFCI's do work, isn't one of main reasons it is required to protect the entire branch circuit because of vulnerabilities in NM cable? After all they have allowed metallic wiring methods then AFCI at first outlet.

If reasoning is because of vulnerability of NM cable then why not AFCI requirement for all NM cable regardless of circuit voltage/current rating?

Also in the furnace application, about the only thing that is much risk for electrical fire (presuming good installation and maintenance) is more likely in the supply circuit, the furnace itself would probably contain anything that occurred within.

If anything this is another case where it would likely contain anything long enough for GFPE to catch it once it starts producing fault current.

I don't believe such an appliance is all that likely to start a fire as a result of arcing, not that arcing can't occur, but will likely be contained enough it won't spread before it either develops a ground fault and trips OCPD or burns itself out. At 120 volts to ground it probably burns itself out most cases.

I have seen 277 volts to ground continue to arc many times, can't recall ever seeing 120 to ground not clearing itself, yet they push the code to use these products on 120 volt circuits:ashamed:

I agree pretty much with all of what you say, but the argument against GFCIs or AFCIs tripping while actually doing the job they are designed for, is weak. IMO, of course.

 

[mlnk]

Per 2017 NEC all outlets in the garage and outdoors are not required to be AFCI protected, except a laundry area in the garage requires AFCI protection. Since the FAU is not mentioned, I think if in the garage or in a utility enclosure that opens into the garage or to the exterior, it is not required to have AFCI protection. The circuits running to these areas do not need to be in metallic conduit either. Up for debate is a FAU enclosure which opens into the dwelling unit. I think this is not a closet or storeroom, so still not required, but some inspectors may disagree. I do not know why people are talking about RMC...the requirement for fire alarms, home security, and snow and ice melting is metallic conduit so flex, EMT, AC, and MC will comply. Of course any connection to a FAU is an outlet...an outlet which I believe in most locations, does not require AFCI.

 

[al hildenbrand]

Aside from all the NEC Bible discussion about this, who among you (and let's have a show of hands) would want an AFCI protected circuit on their furnace during a winter snow storm when it's about 6 degrees outside ? Code requirement or not, this is a bad idea IMHO.

I am inclined to agree. The furnace, itself, is awky enough, without adding the solid-state-safety-sniffer to the control of the branch circuit overcurrent protective device. The manufacturer refusal to explain, in technical detail, their solutions to the Grand Concept of AFCI has always stuck in my craw, and still unsettles me.

 

[Dennis Alwon]

I do not know why people are talking about RMC...the requirement for fire alarms, home security, and snow and ice melting is metallic conduit so flex, EMT, AC, and MC will comply. Of course any connection to a FAU is an outlet...an outlet which I believe in most locations, does not require AFCI.

The rmc comes from one of the methods listed in 210.12

(5) If RMC, IMC, EMT, Type MC, or steel-armored Type AC
cables meeting the requirements of 250.118, metal wireways,
metal auxiliary gutters, and metal outlet and junction
boxes are installed for the portion of the branch
circuit between the branch-circuit overcurrent device and
the first outlet, it shall be permitted to install a listed
outlet branch-circuit type AFCI at the first outlet to
provide protection for the remaining portion of the
branch circuit.

 

[mbrooke]

Given the assumption that AFCIs do work, who would rather it trip during a winter storm, or suffer the resulting fire without one?

But your not going to prevent a fire with one. The breaker is still going to trip fast enough on a short circuit and arcing is the end stage of joule heating- not the beginning. NFPA just aims at being the personification of this:

 

[mbrooke]

This is the same argument we heard about gfci on refrigerators.

Said argument may be rooted in scientific reason as well as statistics or lack their of:

Where "f" plays the red herring.

 

[goldstar]

Given the assumption that AFCIs do work, who would rather it trip during a winter storm, or suffer the resulting fire without one?

You pose a good argument. However, the key word in your argument is ASSUMPTION. If you stop and think about this for a moment, if there's a direct run of NM cable from the breaker panel to the furnace, where is the most likely place an arc fault could occur (aside from a staple through the wire) ? It's going to either be at the disconnect switch for the furnace or at the breaker. In either case could the wire heat up to a point where the insulation burns off and causes a fire ? I doubt anything inside the furnace would trip an AF breaker but I'm sure we've all seen switches on vacuum cleaners trip AF breakers. I'm not disputing what the Code states. I can read it like everyone else but I think there should be an exception in some cases IMHO.