arc fault and EMT

[mfphillipps]

Within residential dwelling, if my entire run (panel to plug) of conductor is in EMT, is an arc fault protection needed?

 

[Dennis Alwon]

If there are no other devices on the circuit then, you would not need any afci

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.

 

[Jerramundi]

If there are no other devices on the circuit then, you would not need any afci

I don't mean to question the Gods (haha), but are you sure? Would that first outlet still not have to be AFCI protected per 210.12?

I believe all your quote is doing is providing you the ability to do AFCI protection (line-load style) at the first opening as opposed to at the panel... but installing a listed AFCI device at the first opening and doing line-load protection still protects that first outlet w/ the device itself... and the line-load set-up for the rest of the branch circuit (if there is one).

I would argue that first opening still requires AFCI protection per 210.12... unless you have a local amendment like Chicago does which says AFCI is not necessary for hard conduit installations.

 

[mfphillipps]

250.118... so does that mean if my entire circuit is in EMT and metal boxes, I do not need a AFCI at any point?

 

[Dennis Alwon]

No you still need afci for the receptacles to protect anything plugged in to it.

 

[Dennis Alwon]

I don't mean to question the Gods (haha), but are you sure? Would that first outlet still not have to be AFCI protected per 210.12?

I believe all your quote is doing is providing you the ability to do AFCI protection (line-load style) at the first opening as opposed to at the panel... but installing a listed AFCI device at the first opening and doing line-load protection still protects that first outlet w/ the device itself... and the line-load set-up for the rest of the branch circuit (if there is one).

I would argue that first opening still requires AFCI protection per 210.12... unless you have a local amendment like Chicago does which says AFCI is not necessary for hard conduit installations.

You are correct. What I wrote did not come out properly.... The afci is still needed at the receptacle itself. The afci is not needed at the panel..

 

[Jerramundi]

250.118... so does that mean if my entire circuit is in EMT and metal boxes, I do not need a AFCI at any point?

250.118 is Types of Equipment Grounding Conductors (EGC's). It basically allows you to use the EMT itself as a ground fault current path as opposed to a wire type EGC. It is NOT permission to NOT do AFCI protection.

Dennis' quote, which is actually 210.12(A)(5), is part of 210.12 - Arc Fault Circuit Interrupter Protection.

It allows you provide AFCI protection for the circuit at the first opening with an AFCI device, as opposed to an AFCI breaker at the panel, if you follow the requirements of 250.118.

But, the first part of 210.12 requires AFCI protection for ALL 120V, single phase, 15 and 20 amp branch circuit suppling outlets or devices installed in particular areas within a dwelling unit... which at this point is pretty much everywhere... but not literally.

I would argue you are still required to provide AFCI protection per 210.12.

 

[mfphillipps]

Got it. Thank you.

 

[hbiss]

It allows you provide AFCI protection for the circuit at the first opening with an AFCI device, as opposed to an AFCI breaker at the panel, if you follow the requirements of 250.118.

And why would anybody want to do that instead of a breaker unless you had to?

No you still need afci for the receptacles to protect anything plugged in to it.

As well as the receptacle itself.

-Hal

 

[Jerramundi]

And why would anybody want to do that instead of a breaker unless you had to?

Well, it is cheaper than the breaker in most cases, but one heck of a logistical nightmare to have protection methods scattered throughout the house.

I used them for one customer who hired me to add ceiling fans to his bedrooms, but had an old FP panel that he didn't wanna replace at the time despite my recommendation to do so, so I installed AFCI's in the first openings.

 

[jaggedben]

What about lighting fixtures with no replaceable bulbs (e.g LED)? Surely those don't require AFCI if the metal raceway is used.

 

[packersparky]

What about lighting fixtures with no replaceable bulbs (e.g LED)? Surely those don't require AFCI if the metal raceway is used.

Yes it would require AFCI protection. The section requiring it is what Dennis posted in post #2

 

[jaggedben]

Yes it would require AFCI protection. The section requiring it is what Dennis posted in post #2

Did they mean to do that? I mean it seems ridiculous.

 

[Fred B]

Excuse the stupid question. Regarding requirements listed in 210.12(A) I'm familiar with product listed in (1) and (4), but what are the other products listed in (2) and (3)? What makes product in (2) different than (1) that it requires additional protection at first outlet box with use of (2)? Is there a clear recognizable difference between seemingly similar products? It would seem to be an important need to be able to recognize these products to avoid noncompliance.

 

[Dennis Alwon]

Excuse the stupid question. Regarding requirements listed in 210.12(A) I'm familiar with product listed in (1) and (4), but what are the other products listed in (2) and (3)? What makes product in (2) different than (1) that it requires additional protection at first outlet box with use of (2)? Is there a clear recognizable difference between seemingly similar products? It would seem to be an important need to be able to recognize these products to avoid noncompliance.

For a long time these devices weren't even on the market but I have heard they are or will be. I actually wrote a proposal to do away with that section but obviously they knew more than I did. It seems quite ridiculous to me to use 2 devices instead of one. I am not sure why this product is made or where it would be beneficial.

 

[augie47]

Excuse the stupid question. Regarding requirements listed in 210.12(A) I'm familiar with product listed in (1) and (4), but what are the other products listed in (2) and (3)? What makes product in (2) different than (1) that it requires additional protection at first outlet box with use of (2)? Is there a clear recognizable difference between seemingly similar products? It would seem to be an important need to be able to recognize these products to avoid noncompliance.

The product in (2) is a "listed branch circuit/feeder type AFCI". These were the 1st generation AFCIs before the "combination"

 

[Jerramundi]

For a long time these devices weren't even on the market but I have heard they are or will be. I actually wrote a proposal to do away with that section but obviously they knew more than I did. It seems quite ridiculous to me to use 2 devices instead of one. I am not sure why this product is made or where it would be beneficial.

Yea. I always wondered about that too. (1) An AFCI breaker + (2) a listed AFCI device at the first opening.. always seemed redundant to me.
I've always done one or the other and just ignored the other parts of 210.12

 

[Jerramundi]

Did they mean to do that? I mean it seems ridiculous.

Lighting, smoke detectors, everything that's 120V and within the listed areas of a dwelling unit. It's clear in the verbiage when they say it has to protect the branch circuit wiring feeding the outlet (outlet meaning any point at which the wires are accessible such as a junction box or light fixture, not just the receptacle).

Seems pretty explicit and intentional to me.
If you think about what an AFCI is protecting against, that is parallel and series arcs in the wiring, it makes sense... theoretically anyway. I don't want to open Pandora's box and start a debate about AFCI requirements, lol.

 

[jaggedben]

Lighting, smoke detectors, everything that's 120V and within the listed areas of a dwelling unit. It's clear in the verbiage when they say it has to protect the branch circuit wiring feeding the outlet (outlet meaning any point at which the wires are accessible such as a junction box or light fixture, not just the receptacle).

A juction box is not a outlet. Read the Article 100 definition.

Seems pretty explicit and intentional to me.
If you think about what an AFCI is protecting against, that is parallel and series arcs in the wiring, it makes sense... theoretically anyway. I don't want to open Pandora's box and start a debate about AFCI requirements, lol.

If wiring protected by metal wiring methods does not have to be protected, then why do I need protection at the outlet the if the circuit never extends beyond such wiring methods? The protection requirement makes some sense if the device is a receptacle, or a light fixture with exposed live parts in the socket when a bulb is removed (or into which someone can screw an old fashioned ungrounded receptacle). It doesn't make any sense if the device at the final box is the end use of the circuit. It seems like they didn't think of this.

 

[hbiss]

If wiring protected by metal wiring methods does not have to be protected,

Yes it does.

-Hal