protecting NM cable in pole barns, and unfinished garages

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Stevenfyeager

Senior Member
Location
United States, Indiana
Occupation
electrical contractor
Is it required to protect NM cable in pole barns? In unfinished garages? Once I had an inspector have me use conduit to protect NM cable in a actual barn (where livestock could be) up to 8 feet high. Thank you.
 
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MAC702

Senior Member
Location
Clark County, NV
Haven't checked a recent book, but this is what I remember, as I found on this post from 2000*: Where the NM cable may be exposed to physical damage, Section 336-6(b) requires that the cable be protected. This protection can be by installing it in conduit, electrical metallic tubing (EMT), Schedule 80 PVC, pipe, guard strips, listed surface metal or nonmetallic raceways, or by any other means that will provide suitable protection for the cable.

*From here: http://www.ecmag.com/section/codes-...nonmetallic-sheathed-cable-exposed-or-raceway

That should give you some thought until I or someone can check the current book to make sure.
 
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kwired

kwired

Electron manager
Location
NE Nebraska
If livestock are intended to be present ordinary NM cable isn't permitted to be used per 547.5. NMC (if you can find such a thing) is allowed, otherwise most use UF cable, if they are going to use a cable wiring method.

Protection of pretty much all wiring methods from animals is a good design decision regardless of what NEC may otherwise say for those 547 applications.

Otherwise you see some differences from one place to another in what the AHJ's may want or call physical protection in such applications where the cable will be left exposed.
 
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retirede

Senior Member
Location
Illinois
I live in a rural area and would guess I've been in nearly 100 pole barns. Some used for animals, some machinery storage, some workshops..... Every one I remember being in that had exposed NM, showed some level of damage to the wiring. I wouldn't do it even if allowed.
 
kwired

kwired

Electron manager
Location
NE Nebraska
retirede said:
I live in a rural area and would guess I've been in nearly 100 pole barns. Some used for animals, some machinery storage, some workshops..... Every one I remember being in that had exposed NM, showed some level of damage to the wiring. I wouldn't do it even if allowed.
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Worse yet is partially exposed NM, rodents seem to find the concealed spots and remove covering from the cable/insulation from conductors.
 
kwired

kwired

Electron manager
Location
NE Nebraska
retirede said:
Doesn't even have to be a concealed spot! If they can get to it, they'll chew on it.
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Correct, but I seem to find more damage in concealed spots then I do in open spots. They will spend more time in a place they think is safe then they will in an open space where predators may spot them.
 
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blkmagik21

Senior Member
Location
Kennewick
I've seen a mouse run into an open KO in a panel then found him when opening up a j box. He ran through the conduit that had wires in it.


Sent from my iPhone using Tapatalk
 
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