NM-B protection from physical damage

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badjeepr

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Exposed type NM-B cable has been accepted as "protected from physical damage" above a heighth of 8'but i cannot find this rule written anywhere. Article 334-15B states protection "where necessary". Is it left up the the AHJ?
 
The rule for protecting exposed NM cable from physical damage is 334.15.

The 8' rule that I believe you are talking about if for direct-buried conductors emerging from grade. (See 300.5(D)(1))

Chris
 
badjeepr said:
Exposed type NM-B cable has been accepted as "protected from physical damage" above a heighth of 8'but i cannot find this rule written anywhere. Article 334-15B states protection "where necessary". Is it left up the the AHJ?
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Outdoors is bottom 8 feet, just like Chris pointed to in 300.5(D)(1).
Indoors on the wall, is protected "where necessary" [334.15(B)] as you stated, which is up to interpretation.
. . And where conduit is not deemed necessary, 334.15(A) says: "closely follow the surface of the building finish or of running boards".
Indoors on the ceiling, between ceiling joists is 334.15(C) and doesn't require protection.
 
badjeepr said:
Exposed type NM-B cable has been accepted as "protected from physical damage" above a heighth of 8'but i cannot find this rule written anywhere. Article 334-15B states protection "where necessary". Is it left up the the AHJ?
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Could be a local code.
 
I just had to laugh at that.

I have had a few inspectors mention the 8' rule here in the bay area. I never bothered to see if it really is an amendment - I just make sure the romex is always protected from damage.

~Matt
 
peter d said:
I put an electric fence around all my NM cable jobs.
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Never thought of that... usually people dont mess with it to begin with, but for the few that have crazy axe wielding parties, guess it cant hurt to play it safe.
 
not sure where your located, but I know that in Oregon that is the case and its found in the Oregon Specialty Code as an ammend. to 334
 
what are some of your favorite local amendments to the code that actually make for a

what are some of your favorite local amendments to the code that actually make for a

good job.
no flex below 2.42m [or something] meters
don't forget
one cable - one hole. :roll:
what are some of your favorite local amendments to the code that actually make for a good job.

i heard that nyc is only hard pipe and mc cable. that's great!
 
wyreman said:
good job.
don't forget
one cable - one hole. :roll:
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What locality are you referring to for the one cable one hole rule? Some believe this rule applies in San Francisco, but it doesn't.

The 8' rule for romex is a local code here though.

There is also a six foot maximum rule for exposed flex but you can run it in the wall any length you want.
 
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wyreman said:
what are some of your favorite local amendments to the code that actually make for a good job.
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In Ohio before we went to state control only, many of the cities had a rule that set coupling conduit runs were required to have an equipment grounding conductor [sized per 250.122, of course].
 
set coupling conduit runs ​


don't you think these are better than compression fittings?
 
peter d said:
I put an electric fence around all my NM cable jobs.
Click to expand...

isn't an electric fence just a heavy capacitor hanging on the barbed wire?
any farmers out there?

i heard of one guy says he used to be able to run a drill off a cold water pipe and the power inductively generated under a high voltage line :roll:
who knows?
 
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