Stacking MC cables and NEC 330.15

Tainted

Tainted

Senior Member
Location
New York
Occupation
Engineer (PE)
I need to run a lot of cables to apartments.

In the 2020 NEC, 330.15 says I need run exposed cable closely to the surface of the building finish:

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Does this mean I cannot run cables with hanger supports like in the picture below? What if I want to stack cables on top of each other, how can I comply with 330.15 if I want to stack cables if I cannot use hanger supports?
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Article 100 gives this for the definition of exposed

Exposed (as applied to wiring methods). On or attached to the surface or behind panels designed to allow access. (CMP-1)

MC run similar to the picture you posted is done all the time. If there is a violation it will be something related to local amendments in your area.
 
ActionDave said:
Article 100 gives this for the definition of exposed

Exposed (as applied to wiring methods). On or attached to the surface or behind panels designed to allow access. (CMP-1)

MC run similar to the picture you posted is done all the time. If there is a violation it will be something related to local amendments in your area.
Click to expand...

I see but I'm not sure if I'm misinterpreting the code. The picture I provided shows that the cable hangs on the support in mid air and does not follow the surface of the building finish as required by the code. Wouldn't this be a violation?

What exactly is meant by "shall closely follow the surface of the building finish"
 
ActionDave said:
When you are strapping MC to a wall or ceiling you have to follow the surfaces, you can't go halfway up the wall and then make a forty five degree jump to the ceiling.
Click to expand...
What I am going to do is use uni-strut on the wall to install stacked MC cable, then run cables up close to the ceiling and transition to hanger supports. When I transition to hanger supports I am not strapping the MC cables to the ceiling because I am strapping them onto the hanger supports. Doesn't this violate 330.15?

My interpretation to "shall closely follow the surface of the building finish" is that the cables need to be strapped and supported at the surface of the building finish which means you cannot have hanger support? Because with hanger support you're not strapping the cables at the building finish.
 
Since MC cable is permitted to be installed in cable tray you could install a basket type cable tray on those hangers and install as many MC cables as 392.22 allows.
 
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