Multiconductor NM Cable On Concrete Floor

[OhioAviator]

Hello all,

I have a situation that I'm just not sure if it meets NEC and OSHA requirements. The situation is this...
We have an 18" aluminum cable ladder with 6" side rails and 9" rung spacing. This cable ladder is fastened to 5/8" Unistrut, which itself is fastened to a concrete floor. Installed in the cable ladder are several power cables, a divider, and several multiconductor NM cables. About 3 feet away from the end of the cable ladder, the electrical contractor dipped the multiconductor NM control cables down underneath the cable ladder and continued the run of control cables along the concrete floor (running underneath the cable ladder) where they terminate via box connectors into a control cabinet.

I wish I could paste an image from my computer hard drive of what I'm describing, but apparently, I'm not permitted to do that.

Basically, my question is... are NM multiconductor control cables permitted to lay on a concrete floor even though it's protected by a cable ladder immediately above?

Thanks in advance!

 

[BN4537]

NM cable is not permitted to be installed where "subject to physical damage".

"Subject to physical damage" is a subjective interpretation. If it's not likely to get hit, stepped on, run over, or damaged by a weed eater, I would be ok with it. Others here would say that you need to put it in a conduit. If you need a clearer answer for where you are at, contact your local electrical inspector and find out what he thinks is "subject to physical damage".

Now, you have described concrete and metal structures... is this a wood framed building? Because in non-combustible buildings (steel and concrete), normally NM cable needs to be located inside a wall where it can be protected from fire by the drywall.

Edit: By NM multiconductor control cables, do you mean Romex or more like some kind of CAT 6 low-voltage wiring?

 

[Gregg Harris]

NM can be run in a ladder tray provided it is rated for it.

NEC 392.3 and 334.10(4)

 

[Paul Sweet]

If the cable tray has 9" x 18" holes between rungs it would be easy for somebody to step on the NM. It sounds like a major tripping hazard, as well as making the path of travel non-accessible.