NM Question

[jwelectric]

You could remove the outer jacket from the NM cables and install the conductors within the nipple but now you may have an issue...

For a volley of references to fail such an installation, look at my last post in this thread. What do you think? Am I stretching it, or interpreting the quoted sections appropriately?

Great job George.

 

[77401]

Has anyone out there actually had a situation where they stipped the sheath on NM, other than tailing in device and junction boxes?

Let me see if I can give an example...Up north, Install a receptacle in an unfinished basement on the exterior Cement wall. The romex enters into a 1/2" EMT with a (not sure of the name) Set screw connector that has a romex clamp on it, (a romex to Emt coupling?). down the EMT to a handy box.
Yes we strip the insulation.

Down South here....Feeding the A/C condensor on the outside of the house, fed with an 8/2 Romex. Same hook up thru the 1/2" EMT to the Pull out Disconnect.

If you don't need the outer covering strip it off. I've never ever seen an inspection fail for stripping off the outer covering in a conduit as long as the covering is on when it enters.

 

[jwelectric]

317.4(B) states that a cable MUST be secured to a box
312.5(C) states that a cable MUST be secured to the enclosure

I can?t help what has passed or not passed it is a violation to strip the sheathing off NM cable and install it in a raceway.

 

[77401]

317.4(B) states that a cable MUST be secured to a box
312.5(C) states that a cable MUST be secured to the enclosure

I can?t help what has passed or not passed it is a violation to strip the sheathing off NM cable and install it in a raceway.

317??? Not in my code book
312.5c is about protection of the cable

Can you explain "cable must be secured to the Enclosure"

2005 NEC???

 

[bjp_ne_elec]

312.5(C) Exception - doesn't this allow the NM not to be secured to the enclosure as one of the expceptions?

jw - I'm also interested in hearing how you secure cables to enclosures, etc.

And again - does anyone out there have a photo that would help clear my understanding of what the Exception to 312.5(C) is all about.

Thanks

Brett

 

[jwelectric]

317??? Not in my code book
312.5c is about protection of the cable

Can you explain "cable must be secured to the Enclosure"

2005 NEC???

312.5(C) Cables. Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.
314.17(C) Where nonmetallic-sheathed cable or multiconductor Type UF cable is used, the sheath shall extend not less than 6 mm (? in.) inside the box and beyond any cable clamp. In all instances, all permitted wiring methods shall be secured to the boxes.

My bad on the ?317? it was a type-o.

Notice the very last sentence of 314.17(C), In all instances, all permitted wiring methods shall be secured to the boxes.

If a panel in surface mounted there is an exception found in 312.5(C) that will allow a chase to be used under restrictions.
In 334.15(C) we are allowed to install NM cable is a conduit to protect the cable.

334.15(C) NM cable used on a wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing. Conduit or tubing shall utilize a nonmetallic bushing or adapter at the point the cable enters the raceway. Metal conduit and tubings and metal outlet boxes shall be grounded.

In all cases to install the NM cable in the conduit for protection it is required to be a surface mount installation on the inside of the building.

 

[jwelectric]

312.5(C) Exception - doesn't this allow the NM not to be secured to the enclosure as one of the expceptions?

(e) The cable sheath is continuous through the raceway and extends into the enclosure beyond the fitting not less than 6 mm (? in.).

jw - I'm also interested in hearing how you secure cables to enclosures, etc.

With a clamp

And again - does anyone out there have a photo that would help clear my understanding of what the Exception to 312.5(C) is all about.

Thanks

Brett

No I don't have a picture of this type of installation but I will find one

 

[George Stolz]

312.5(C) Exception - doesn't this allow the NM not to be secured to the enclosure as one of the expceptions?

Yes. But when we are handed ten provisions in that exception (three are concealed in the opening sentence), all of which must be observed to use the exception, I would call that a "tall" exception to the rule.

I'm also interested in hearing how you secure cables to enclosures, etc.

Personally, I recess panels, and install plastic romex connectors.

If I have to surface mount a panel, then I install a running board and secure the romex within 12" of the panel, and use romex connectors.

And again - does anyone out there have a photo that would help clear my understanding of what the Exception to 312.5(C) is all about.

I don't have a photo, but I can give you a verbal, maybe that might help?

I use a ram-set to mount an indoor panel to the wall of a basement. I now have to run the cables into the panel, but my jurisdiction (say, San Francisco) does not allow romex under 8' to be exposed at all, it must be sleeved in a conduit. This presents me with a problem, because (the main rule of) 312.5(C) says that the cables must be secured to (clamped to) the enclosure.

I'd like to use a 2" or 2.5" EMT right up the wall.

I'm in luck: as long as I adhere carefully to the exception, I can skip securing the cables to the enclosure.

 

[jwelectric]

Here is a link to a picture of how this panel is to be installed with explanations
http://i3.photobucket.com/albums/y63/jwelectric/PipePanel.jpg

 

[77401]

D ...Seal the opening...I just how it that accomplished.

 

[iwire]

D ...Seal the opening...I just how it that accomplished.

A few pages of a code book wadded up and stuffed in the pipe. :wink:


Duct seal would be my choice or spray foam.

 

[bjp_ne_elec]

Duct Seal.

I'd be afraid of the spray foam having an adverse reaction with the sheath of the NM.

You haven't used that, being in this trade. Use it to build up around burndy connectors when splicing - can form a nice smooth "ball" so that you can rubber tape the splice joint. Every electrician needs this in their truck.

 

[iwire]

I'd be afraid of the spray foam having an adverse reaction with the sheath of the NM.

In this area spray foam is often used around NM for sealing holes in non-fire rated construction.

Duct seal in a burndy?

That is a new one on me but sounds like a good way to smooth out the surface.

But I have pretty much stopped using split bolts in favor of newer methods.

 

[peter d]

But I have pretty much stopped using split bolts in favor of newer methods.

like solder, for instance? :lol:

 

[busman]

I don't have my Code Handbook with me today, but there is a section in the 1999 Handbook where it discusses the need for junction boxes. In this section the commentary specifically discusses the exception to the need for a JB where transitioning from cable to conduit and uses the example of a romex wired basement with a wall mounted receptacle. The commentary discusses stripping the sheathing from the romex and using a fitting to transition from romex to conduit. For me, this is a common method of wiring unfinished basements. Maybe someone with the Handbook could post this or I will when I get home.

Mark

 

[jwelectric]

2005 HANDBOOK
300.15(F) Fitting A fitting identified for the use shall be permitted in lieu of a box or conduit body where conductors are not spliced or terminated within the fitting. The fitting shall be accessible after installation.

Where a cable system makes a transition to a raceway to provide mechanical protection against damage, 300.15(F) permits the use of a fitting instead of a box. For example, where nonmetallic-sheathed cable that runs overhead on floor joists and drops down on a masonry wall to supply a receptacle needs to be protected from physical damage, a short length of raceway is installed to the outlet device box. The cable sheath is removed for the length of the raceway. The cable is then inserted in the raceway and secured by a combination fitting that is fastened to the end of the raceway.

But this contradicts

2005 NEC
310.11 Marking.
(A) Required Information. All conductors and cables shall be marked to indicate the following information, using the applicable method described in 310.11(B):
(1) The maximum rated voltage
(2) The proper type letter or letters for the type of wire or cable as specified elsewhere in this Code
(3) The manufacturer?s name, trademark, or other distinctive marking by which the organization responsible for the product can be readily identified
(4) The AWG size or circular mil area
FPN: See Conductor Properties, Table 8 of Chapter 9, for conductor area expressed in SI units for conductor sizes specified in AWG or circular mil area.
(5) Cable assemblies where the neutral conductor is smaller than the ungrounded conductors shall be so marked

When the sheathing is stripped off the conductors there is no marking on the conductors and is now in violation of 310.11.
The rule in NC is that the sheathing CANNOT be striped off.

 

[busman]

Mike,

Thanks for the assist. I'm not sure it is a contradiction. I would say that unless one were to strip back a very long length of sheathing from the cable, the conductor type can be identified by tracing them to the cable they emerge from. I see this as different than stripping out some romex to get pigtails or short runs and having no way to determing the type of the conductors.

All that said, if there is a local rule then that's clear enough.

Another thought is that bare conductors would also violate the marking rule.

Thanks again,

Mark

 

[mikeames]

When the insulation is striped off NM it is no longer considered a cable. It become individual conductors.

 

[infinity]

Mike,

Thanks for the assist. I'm not sure it is a contradiction. I would say that unless one were to strip back a very long length of sheathing from the cable, the conductor type can be identified by tracing them to the cable they emerge from. I see this as different than stripping out some romex to get pigtails or short runs and having no way to determing the type of the conductors.

All that said, if there is a local rule then that's clear enough.

Another thought is that bare conductors would also violate the marking rule.

Thanks again,

Mark

I agree with Mark. This entire argument is silly. If I can see the NM cable entering the conduit who really cares if the cable has it's outer covering removed. Even if it isn't removed, unless this is a glass conduit, I still can't see the outer jacket of the cable. :lol:

 

[M. D.]

With duct seal????
Mike good job!