MC cable in raceways

[Little Bill]

Fourth (more significant with NM than with MC), comes the argument of whether or not the unsheathed wire is allowed if it is not properly labelled along its length to indicate the underlying wire type or whether a cut sheet or other documentation of the wire type is sufficient.

I can't speak to every brand of MC cable but the 2-3 brands I buy here are all printed/labeled on the individual conductors under the armor. Just like any THWN-2 conductors are.

 

[Smart $]

I can't speak to every brand of MC cable but the 2-3 brands I buy here are all printed/labeled on the individual conductors under the armor. Just like any THWN-2 conductors are.

Even with that aside, from a bigger-picture kind of perspective, which would you consider the better wire protector: spiral-wrapped interlocked armor or EMT?

 

[peter d]

Even with that aside, from a bigger-picture kind of perspective, which would you consider the better wire protector: spiral-wrapped interlocked armor or EMT?

:roll:

That really is irrelevant. Obviously, if there was a need for physical protection, then MC would not be a good choice.

 

[Strathead]

So in regards to the last paragraph in 358.22 and section 310.(A)(7) you think they mean to run MC cable in a raceway with the jacket?

I think that 310 is absolutely referring to unstripped MC run in conduit. However I think that most of the questions you refer to are asking exactly what you are answering. Also, it is refreshing to see decent work that isn’t as nit picky about minor things like the 5 foot rule that we often digress to on this forum.

 

[Smart $]

:roll:

That really is irrelevant. Obviously, if there was a need for physical protection, then MC would not be a good choice.

It's not irrelevant from a bigger-picture perspective. From a physical protection standpoint, EMT is better. From most any other standpoint, EMT is better. Armor is only better in flexibility, and that quality lends to an easier installation.

Face it. The issues brought up by GoldDigger are nit picking.

 

[Smart $]

I think that 310 is absolutely referring to unstripped MC run in conduit. However I think that most of the questions you refer to are asking exactly what you are answering. Also, it is refreshing to see decent work that isn’t as nit picky about minor things like the 5 foot rule that we often digress to on this forum.

Raceways are required to be installed complete. iwire posed the question and it has gone unanswered... If MC is required to be run in the raceway unstripped, how do you terminate the MC?

 

[peter d]

It's not irrelevant from a bigger-picture perspective. From a physical protection standpoint, EMT is better. From most any other standpoint, EMT is better. Armor is only better in flexibility, and that quality lends to an easier installation.

Face it. The issues brought up by GoldDigger are nit picking.

You go ahead and run all the EMT you want then. Here in the real world, we use MC for just such a situation that Iwire had.

I actually worked on a similar job last winter. We had to install a panel in a school building about 175' away from the electric room. The only ways to get there was run EMT across a high gym ceiling which necessitated a lift, lots labor, and coring through several block walls. Or, we could run large MC (2/4) through a very crowded but accessible drop ceiling. We ran the MC cable.

 

[Smart $]

You go ahead and run all the EMT you want then. Here in the real world, we use MC for just such a situation that Iwire had.

I actually worked on a similar job last winter. We had to install a panel in a school building about 175' away from the electric room. The only ways to get there was run EMT across a high gym ceiling which necessitated a lift, lots labor, and coring through several block walls. Or, we could run large MC (2/4) through a very crowded but accessible drop ceiling. We ran the MC cable.

I'm not talking EMT vs. MC. I'm talking armor-stripped MC cable wires in EMT at either or both ends of the MC.

 

[peter d]

I'm not talking EMT vs. MC. I'm talking armor-stripped MC cable wires in EMT at either or both ends of the MC.

I think Iwire already asked a good question in regard to that. If we can't strip MC cable because the conductors are part of a listed assembly, then are we allowed to strip it and terminate it in a panel or a junction box?

 

[Strathead]

Raceways are required to be installed complete. iwire posed the question and it has gone unanswered... If MC is required to be run in the raceway unstripped, how do you terminate the MC?

Where doe it say it has to be terminated? What I make my guys do is put a redhead (anti short bushing in the end and tape with electrical tape, but I think that is just good work practice. I feel it just needs to be strapped within 1 foot of where it enters the raceway.

 

[iwire]

Where does it say it has to be terminated?

300.15

What I make my guys do is put a redhead (anti short bushing in the end and tape with electrical tape, but I think that is just good work practice.

I do it that way as well with some sort of fitting that grabs the armor but strictly speaking that rarely complies with 300.15.

 

[Smart $]

Where doe it say it has to be terminated? What I make my guys do is put a redhead (anti short bushing in the end and tape with electrical tape, but I think that is just good work practice. I feel it just needs to be strapped within 1 foot of where it enters the raceway.

How does it enter the raceway if the raceway is installed complete?

 

[Smart $]

I think Iwire already asked a good question in regard to that. If we can't strip MC cable because the conductors are part of a listed assembly, then are we allowed to strip it and terminate it in a panel or a junction box?

Logic prevails.

But I am left wondering if you can stay on subject in any conversation?

 

[iwire]

Nice looking work Iwire.

Quick question.



Is that approved? Or just SOP in your area? I rarely work with MC cable. My entire plant is RAC.

Thanks.

Regarding the solid wire used to secure the cables.

Not really SOP, typically in hidden areas we use tie wraps or 16 AWG steel bailing wire, but the 3/3 is a bit heavy for the tie wraps I had and I did not have bailing wire. So the solid 10 was handy, it is very strongly secured.

In exposed areas we use MC i hole clips, EMT clips or minnis, or if on strut we will use strut clips to hold bundles of 3 or 4 cables.

The inspectors around here are pretty good about what we use as long as it is in fact secure. Some of the listed products such as Caddy CJ-6 MC / NM cable supports are incredibly flimsy so I tend to avoid them.

 

[Strathead]

300.15




I do it that way as well with some sort of fitting that grabs the armor but strictly speaking that rarely complies with 300.15.

I don't read 300.15 that way at all.

 

[Strathead]

How does it enter the raceway if the raceway is installed complete?

Why is it so necessary to get so ridiculously picky here? Article states that MC is allowed to be installed in raceway. It doesn't say conductors stripped out of MC may be... I don't feel your question has any merit. For example, when you run SEU in a trench but it must be enclosed in a raceway where it extends up from the ground how do you do that with your same argument. Give me a break.

 

[iwire]

I don't read 300.15 that way at all.

How do you read it?



Part of 300.15

Where the wiring method is conduit, tubing, Type AC
cable, Type MC cable, Type MI cable, nonmetallic-sheathed
cable, or other cables, a box or conduit body shall be installed
at each conductor splice point, outlet point, switch point, junction
point, termination point, or pull point, unless otherwise
permitted in 300.15(A) through (L).

The conduit terminates at the cable, therefore 300.15 requires a box or a fitting.

Fittings must be used as listed.


Remember, I do this all the time so I am 'on your side' but there are some code issues in my pictures.

 

[peter d]

:slaphead::slaphead:

 

[Carultch]

Here's a couple of solutions I've done for this situation. It happened when I inherited PVC Conduits from the rough-in, when my application requires the wire to be enclosed in metal.

 

[iwire]

If you accept that MC cable with the sheath removed is still MC cable, do you also accept that NM cable with the sheath removed is still NM cable?

Yes.

If so, you could not run stripped NM in a wet area even if the individual wires were listed for wet use.

I don't do that.

My strongest argument is that there is a UL specification for MC cable, and what the NEC refers to is something that meets that UL standard.
Once the sheath is removed, you do not have that UL listed and identified product anymore.

And that does not fly because that means I cannot ever strip any cable sheeth to enter an enclsure.

Not even the insulation to make a connection could be removed. Any UL specification for a cable is going to include insulation of the conductor.

Entirely separate from the question of whether the individual conductors, still twisted or untwisted, can be used in a particular way, is the question of whether it is still the wiring method that is referred to in the NEC articles and tables, namely MC.

Its listed as acceptable in the cable, tubing and conduit sections. All of those are wiring methods.

If a particular location allows you to use MC because the wires are protected well enough from physical damage (open stud walls in a garage, for example), are you also allowed to use stripped MC in that location?
(It's still MC, right?)

That is a good question, I will have to ponder that one.

If you put stripped MC into a raceway, do you still have to both secure and support it at regular intervals? (It's still MC, right?)

Stripped or unstripped the support section applies and both the cable and conduit articles say we can do it. So that is just an issue with the .30s of cable sections.

The .30s also conflict with 334.15(C)



Part of 334.15(C) 2014 NEC

Nonmetallic-sheathed cable installed on the
wall of an unfinished basement shall be permitted to be
installed in a listed conduit or tubing or shall be protected
in accordance with 300.4. Conduit or tubing shall be provided
with a suitable insulating bushing or adapter at the
point the cable enters the raceway. The sheath of the
nonmetallic-sheathed cable shall extend through the conduit
or tubing and into the outlet or device box not less than
6 mm (V-1- in.). The cable shall be secured within 300 mm
(12 in.) of the point where the cable enters the conduit or
tubing.