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Old 11-27-2011, 08:34 PM   #1
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Flexible Conduit for GFCI/AFCI


I am wondering if any flexible conduit exists that would allow compliance with 210.8 and/or 210.12 to allow protection to be put in place at the first outlet of the circuit.

Breaker box is in the basement and I am looking to add 2, 20 Amp circuits to the basement and the initial 25 feet or so of the cable run is along the same path. As such, I would like to use conduit and 12/2 NM cable to run from the box to the first receptacle. However, do to ease of transport (I don't have a trunk to easily hold 10 foot lengths) and installation, I would prefer to be able to use some type of flexible steel conduit. HD and Lowes have the steel conduit that comes in "rolls" and the steel APPEARS to be identical to that used with MC cable, however, I do not know if this would be code compliant.

If flexible conduit isn't available that would comply with the code, I am considering simply using MC cable do to the ease of transport and installation.

Any suggestions?

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Old 11-28-2011, 10:55 AM   #2
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Flexible Conduit for GFCI/AFCI


Couple things come into play with your proposal. What code cycle are you using?

Neither 2008 nor 2011 codes require GFCI circuits to be protected in conduit to the first receptacle, section 210.8.

Section 210.12
The flexible conduit you’re speaking of sounds like it could be ‘Flexible Metal Conduit’ (FMC). According to the 2008 code, it cannot be used for the protection of the circuit between the panel and the first receptacle. 2011 code says you can use it, but it has to be encased in no less than 2” of concrete for the portion that runs between the panel and the first receptacle outlet. And though the code doesn’t specifically state that portion has to comply with 250.118 (Types of Equipment Grounding Conductors), I believe that is the intention of the code (look at 2011:210.12 (A) Exceptions 1 & 3), which means that portion cannot be over 6 feet long, to qualify as an equipment grounding conductor. Another problem with doing it this way, is finding a AFCI receptacle. I’m not sure any manufacturer is making them, or whether they have a UL listing. Last I heard was the manufacturers were willing to make them, but there wasn’t a demand in the market, so no-one has.

The way I read 2008 & 2011 about using MC cable:
2008: 210.12 (B) Excpt 1 says ‘steel armored cable’, meeting the requirements of 250.118. I believe steel armored MC that qualifies as an EGC is available, I don’t believe it’s very common. (I know they make MC where the sheathing qualifies as an EGC, I just don’t remember if it’s steel or aluminum).
2011:Mentions MC, but again I believe the intention is for it to meet the requirements of 250.118. (see 2011:210.12(A) excpt #3 for a better wording of the intention).

Long story short…why are you wanting to do it this way? At ~$40 for a AFCI breaker, it’s cheaper and easier to use a breaker than going this other route. Again, finding a AFCI receptacle is probably going to be more difficult.

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Old 11-28-2011, 12:08 PM   #3
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Flexible Conduit for GFCI/AFCI


First off, my mind decided to combined the GFCI and AFCI sections of the code requirements together. I am actually needing GFCI protection as the circuits will be running through the basement into the garage and there will be 2 of them. I am going through a brainstorming exercise of the best way to get power there in a code compliant manner and several ideas have popped into my head.

With your important point that NM cable could be run directy without any conduit it potentially solves most of the problems I was comtemplating as I can simply run 2 runs of NM 12/2 into the garage and install a GFCI receptacle as the first outlet on each circuit.

The only concern that I have here is properly securing the NM cable as the most efficient run of cable would run along the foundation but BEHIND 2 storage rooms that have been built out in the basement. The conduit concept first came into play when I realized that I really had no way of securing the cable behind the rooms, so I was thinking of running some conduit behind the rooms to run the cable through. This led to the issue with running NM cable through conduit which based on some searching appears to be a debated topic of which I cannot really find any place in the code that states it is not allowed. In turn, I started considering just using flexible conduit all the way from the box to the garage and using THHN and possibly wiring it as a MWBC using a double pole 20 amp breaker. I've also tossed in the idea of a using a subpanel protected by a 30A GFCI breaker at the main (I posted a separate question as to whether this was code compliant, 215.9 I believe would allow this).

So I guess my real problem is that I am an overthinker and like the theory of the design too much :-).

Any insight into what you feel the best way might be would be welcomed. Please keep in mind that securing NM cable for about a 10-15 foot span would be close to impossible.
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Old 11-28-2011, 12:14 PM   #4
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Flexible Conduit for GFCI/AFCI


Romex inside conduit is not an issue.
I would not worry about the 10/15 feet where you can not staple the wire up.
I would run a 10/3 with ground and install a 4 circuit subpanel.
Protect the circuits with a gfci receptacle at the first location and call it good.
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Old 11-28-2011, 12:29 PM   #5
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Flexible Conduit for GFCI/AFCI


Cables that are fished are not required to meet the same requirements for being secured.
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Old 11-28-2011, 01:18 PM   #6
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Flexible Conduit for GFCI/AFCI


Thanks all.

Final plan...

NM 10/3 from main box to subpanel in garage, no conduit.

NM 12/2 from subpanel to GFCI outlets from the 2 new breakers. Enclosuring the 12/2 in 3/4 inch FMC simply to protect against damage in the semi-hostile Garage environment would not be an issue and I'm done.
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Old 11-28-2011, 01:23 PM   #7
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Flexible Conduit for GFCI/AFCI


And since I have your attention...

I was also considering adding power to a detached shed...

For this I could use EMT conduit buried at least 18 inches, with THWN 10 gauge wire feeding a subpanel in the shed, standard double pole 30 Amp breaker in the main box with GFCI receptacles from the sub and standard breakers for the lighting?

I also believe I could use NM 10/3 from the breaker box to the exit point of the house where I could use a J-box to transition from NM 10/3 to THWN in conduit leading outside preventing the need to run conduit inside the house.

All correct?
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Old 11-28-2011, 03:24 PM   #8
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Flexible Conduit for GFCI/AFCI


i would not use emt buried, i would use pvc or a simple 10/3 uf cable, with uf cable no need for junction box
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Old 11-28-2011, 03:25 PM   #9
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Flexible Conduit for GFCI/AFCI


Quote:
Originally Posted by dcapone View Post
And since I have your attention...

I was also considering adding power to a detached shed...

For this I could use EMT conduit buried at least 18 inches, with THWN 10 gauge wire feeding a subpanel in the shed, standard double pole 30 Amp breaker in the main box with GFCI receptacles from the sub and standard breakers for the lighting?

I also believe I could use NM 10/3 from the breaker box to the exit point of the house where I could use a J-box to transition from NM 10/3 to THWN in conduit leading outside preventing the need to run conduit inside the house.

All correct?
Yes, but use pvc.
You also need 2 ground rods at the shed, and you need a disconnect at the shed.
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Old 11-29-2011, 08:49 AM   #10
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Flexible Conduit for GFCI/AFCI


Do you need 30 amps out in the shed? If you put a sub-panel out in the shed, then it’s a feeder and needs 2 grounds rods as jbfan mentioned. If you only need 20 amps, then you can use 12/3 as a multiwire branch circuit (unless you need 10/3 for voltage drop), and not put in a sub-panel, use a 2-pole switch as the disconnect. Then you don’t have to put in ground rods.

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