NM conductors in MC?

[flywright52]

I need a 12/2 short whip (4-5 ft) on a residential job requiring MC. I have quite a bit of 3/8" MC sheath. Can I make my own MC cable by pulling the conductors (black, white, bare) out of NM cable and putting that in the empty MC sheath? I can't find any restrictions in the 2005 NEC (art. 330 or references) that would prevent it.

 

[luckylerado]

348.20 Size.
(A) Minimum. FMC less than metric designator 16 (trade
size 1⁄2) shall not be used unless permitted in 348.20(A)(1)
through (A)(5) for metric designator 12 (trade size 3⁄8).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not in excess of 1.8 m (6 ft) for any of the
following uses:
a. For utilization equipment
b. As part of a listed assembly
c. For tap connections to luminaires as permitted in
410.117(C)
(3) For manufactured wiring systems as permitted in
604.6(A)
(4) In hoistways as permitted in 620.21(A)(1)
(5) As part of a listed assembly to connect wired luminaire
sections as permitted in 410.137(C)

Why 2005 and why is MC a requirement for a residential job?

 

[flywright52]

Bad verbiage on my part. It's not really a requirement. I replaced the main panel for HO. The outlets for his work bench were run out of the bottom of the GFI for the service panel. I am adding a new circuit for the workbench outlets and thought I would use MC from the panel to the first outlet (GFI) since it would be difficult to use EMT for the routing. Code should be 2008 in this area, but I did not have one handy.

 

[Dennis Alwon]

The conductors in NM cable are not marked so technically it is not compliant to take them out of the NM jacket and install the conductors in another raceway.

 

[Strathead]

I need a 12/2 short whip (4-5 ft) on a residential job requiring MC. I have quite a bit of 3/8" MC sheath. Can I make my own MC cable by pulling the conductors (black, white, bare) out of NM cable and putting that in the empty MC sheath? I can't find any restrictions in the 2005 NEC (art. 330 or references) that would prevent it.

The real answer is going to be no, for a multitude of reasons. MC sheath is not a raceway. NM conductors aren't listed. Conduit fill requirements, locations 3/8 flex (if it was) is allowed. Do I see any problem with it? No, except if the inspector catches me and makes me come back and change it. At the same time, the cost savings could only be pennies, so it would only be a last minute decision to use what I have on hand.

 

[flywright52]

348.20 Size.
(A) Minimum. FMC less than metric designator 16 (trade
size 1⁄2) shall not be used unless permitted in 348.20(A)(1)
through (A)(5) for metric designator 12 (trade size 3⁄8).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not in excess of 1.8 m (6 ft) for any of the
following uses:
a. For utilization equipment
b. As part of a listed assembly
c. For tap connections to luminaires as permitted in
410.117(C)
(3) For manufactured wiring systems as permitted in
604.6(A)
(4) In hoistways as permitted in 620.21(A)(1)
(5) As part of a listed assembly to connect wired luminaire
sections as permitted in 410.137(C)

Why 2005 and why is MC a requirement for a residential job?

Thanks luckylerado. It didn't click with me that I was looking at the wrong article for FMC! http://forums.mikeholt.com/images/smilies/what.gif
Since this is feeding a branch circuit and none of the exceptions listed, 3/8" was the wrong choice in the first place.

Nick

 

[cowboyjwc]

I had someone do that awhile back and as an inspector I can tell you that it just look's like hack work.

 

[flywright52]

Thanks everyone for your inputs. In the end, I went with EMT