Thread: NM romex

Is it allowed to route two NM cables ontop of each other as shown in the photo? I'm thinking its not allowed.

Also, NM romex is not rated for exterior use, should be in an approved conduit, correct?

And , yes, I caught the wire splices!

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They can remove that wiring when they tear down that poorly constructed deck.

Originally Posted by brianmiller

Is it allowed to route two NM cables ontop of each other as shown in the photo? I'm thinking its not allowed.

I believe most flat crown NM cable staples are approved for use with one or two 'flat' cables (i.e., two conductor cables, thee conductor cables are 'round') as shown.

Also, NM romex is not rated for exterior use, should be in an approved conduit, correct?

Partially correct.

NM cable is not rated for exterior use, correct. NM cable should not be installed along the exterior even if in conduit.

One would need to use an approved insulation, such as UF cable. UF cable is similar to NM cable in that both are non-metallic cables, however, NM cable has a non-metallic sheath with the conductors inside wrapped in paper, whereas UF cable has conductors with insulation rated for being wet which are embedded in an outer sheath which is molded around the conductors totally isolating the conductor from each other. When you try to strip UF cable back, the difference becomes readily apparent as it does not strip back like NM cable does.

UF cable will also be sunlight resistant.

Not so fast Jerry. NM is allowed exterior if: Is in a normally dry location not subject to sunlight.
One application would be under an awning in a liquidtite raceway.
Will admit there are very few instances where an exterior application meets all the criteria.
Bob Smit, County EI

Originally Posted by bob smit

Not so fast Jerry. NM is allowed exterior if: Is in a normally dry location not subject to sunlight.
One application would be under an awning in a liquidtite raceway.
Will admit there are very few instances where an exterior application meets all the criteria.
Bob Smit, County EI

Thats not considered "exposed" then is it?

Rick; No mention of 'exposed'. Was referring to Jerry's remark, 'NM should not be run along exterior even if in conduit'.
As a blanket statement that would not necessarily be true.
As is applied to the particular application pictured in this thread, it is true.
Bob Smit, County EI

Originally Posted by bob smit

Not so fast Jerry. NM is allowed exterior if: Is in a normally dry location not subject to sunlight.
One application would be under an awning in a liquidtite raceway.
Will admit there are very few instances where an exterior application meets all the criteria.
Bob Smit, County EI

Bob,

You are describing a "damp location", not a normally dry location.

- Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.

- Location, Dry. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.

- Location, Wet. Installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

- 334.12 Uses Not Permitted.
- - (B) Types NM and NMS. Types NM and NMS cables shall not be used under the following conditions or in the following locations:
- - - (4) In wet or damp locations

Most AHJ's, including this one, consider my description as a normally dry location if protected under an awning as such and in an enclosed "liquidtight raceway" as I mentioned.
The cable, if it could talk, would say 'this is really dry in here'.

The installation I described fits the criteria and the intent.
Bob Smit, County EI

Originally Posted by bob smit

Most AHJ's, including this one, consider my description as a normally dry location if protected under an awning as such and in an enclosed "liquidtight raceway" as I mentioned.
The cable, if it could talk, would say 'this is really dry in here'.

The installation I described fits the criteria and the intent.
Bob Smit, County EI

"The location", which is what we are talking about, being outside under that porch, is a "damp location" REGARDLESS of any raceway, which is why NM is not allowed outside EVEN IF in a raceway.

The location shown in the photo, which is what is being discussed, is a "wet location", and as such:
- 300.9 Raceways in Wet Locations Above Grade.
- - Where raceways are installed in wet locations abovegrade, the interior of these raceways shall be considered to be a wet location. Insulated conductors and cables installed in raceways in wet locations abovegrade shall comply with 310.8(C).

There were enough AHJ who interpreted the code incorrectly that the code making panels SPECIFICALLY included that in the 2008 code to try to help unconfuse those AHJ who thought that way.

Guess that did not work on all those confused AHJ?

WE confused AHJ's consider in our juristiction that it is the 'enviorment' in which the cable itself is in. In the case I discribed, it is normally dry if not always dry.
Again Jerry, it is the intent; which is that the cable is not subject to normally damp.
Important to remember that the CMP's consider at times not to give clearence to a piticular installation as it might be taking liberties not condusive to the intent.

This is why: 90.4 'AHJ may waive specific requirements in this Code or permit alternate methods where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety'.

This is where all the additional education were required to maintain including semanars and such to be informed of the intent of the Code, becomes necessary.

A little common sense goes along way when working with contractors and this is such a case.
OK if we don't agree on this one Jerry.
Bob Smit, County EI

Originally Posted by bob smit

A little common sense goes along way when working with contractors and this is such a case.

And that common sense says, yes, there may be condensation collecting in that raceway, and, yes, that condensation make that raceway *not* a "dry location", regardless whether or not the raceway is liquid tight conduit or not.

Common sense needs to be applied with ... common sense.

It is okay to have that opinion Jerry.
I'll speak and form my opinion as to decades of experience as a sparky.
Bob Smit, County EI

Originally Posted by bob smit

decades of experience as a sparky.

That also applies to sparky's from the decades when no grounds where used, no GFCI protection was installed, and knob and tube was the preferred method - change, better methods, recognizing safer methods, etc., all that stuff happens over time, resulting in changed opinions based on new experience ... it is called learning and keeping an open mind for new ideas, ideas which were rejected out-of-hand a few years ago but which are now being accepted by the leading majority.

Yep, your choice for sure.

Grounding conductors, gfci's, cable assemblies as opposed to K & T, and limiting NM locations, all good things.
Bob Smit, County EI