334.30 requirements

[jerrynoel]

We have some contractors that think that they can have an 18" loop of NM between the device or lighting box and the first staple, because the staple is only 12" away from the cable connector in the box. The only locations that specifically mentions a measurement along the sheath is A: the Exception under 314.17 (C). And that is only for a plastic 1-gang box. B:The other is 312.5(C) which is specific to cables entering raceways.
Anyone have access to a definitive interpretation regarding this? Our municipal rule is that the code must be very specific and admissible in court. In other words, the "neat and workmanlike manner" is a subjective rule and not enforceable.

 

[Dennis Alwon]

IMO, those guys are pushing the purpose of the rule. The rule is 12" from the box but the purpose is to prevent wires from sticking out of the wall and getting pinched by sheetrock etc. The section below states that nm cable shall be supported and secured by staples at intervals not exceeding 12" from the box. How, pray tell, is nm cable supported 12" from the box. I think it is clear. By their interpretation I can have 4' of wire curled up as long as a staple is within 12". Ridiculous argument IMO.

334.30 Securing and Supporting. Nonmetallic-sheathed
cable shall be supported and secured by staples, cable ties,
straps, hangers, or similar fittings designed and installed so
as not to damage the cable, at intervals not exceeding 1.4 m
(41⁄2 ft) and within 300 mm (12 in.) of every outlet box,
junction box, cabinet, or fitting. Flat cables shall not be
stapled on edge.

 

[jerrynoel]

Dennis, I agree completely. They are trying to parse words to get away from doing a quality install. But without something in writing from a member of the code making panel ( I don't have any of their email addresses), we can't do anything. Same goes for EMT. They could come out from a box, go 2', have a double 90 bend and by the time they get to the 3' radius, could have 7' of raceway.

 

[iwire]

First let me make clear I agree with Dennis about the intent and the rule.

That said

They are trying to parse words to get away from doing a quality install

Is that really the case or are they trying to provide slack in case the conductors get hit by the drywall guys rotozip?

I tend to think it is more about that and I do not see a safety issue in leaving some slack. It can be a huge pain to fix cut off conductors if there is no slack and that leads to non-compliant ways of 'fixing it'.

What safety issue do you see that will be covered by the drywall?

 

[jerrynoel]

Is that really the case or are they trying to provide slack in case the conductors get hit by the drywall guys rotozip?

I tend to think it is more about that and I do not see a safety issue in leaving some slack. It can be a huge pain to fix cut off conductors if there is no slack and that leads to non-compliant ways of 'fixing it'.

What safety issue do you see that will be covered by the drywall?

For installs where the cable enters a pan box, we let that slide because of roto-zips. However when they do it next to a recessed can, there is no danger to the conductors.

 

[Dennis Alwon]

Jerry if you really see an issue with what they are doing then, by all means, have your department make a judgment call. The ec will have to either change it or appeal to the higher ups. It is not your job to provide the formal interpretation by a cmp member.

However, if you think this is a minor battle and not a safety issue then let it be. IMO, there is usually plenty of room to access the can box with a 12" loop.

I might add that Wac makes a smaller can where if you install the can and have a 12" whip you cannot access the jb. We just installed them but I figured out that the can is meant to be installed separate from the frame so you just leave the wires hanging down and there will be more than 12" of slack in the ceiling.

 

[JFletcher]

Welcome to the forum,


It's a service loop and there should be zero issue with leaving one. It's actually a more quality install imo. and they dont violate 334.30. If there is a staple within 12" of the box, it's good. there is nothing that says the wire must be pulled like a banjo string between that staple and the box, it's just usually done that way with NM because it looks a bit neater.

OP, how many electrical boxes have you seen where the conductors are impossibly short, and pigtailing every thing results in an ugly mess of wirenuts that are smashed back in the box? I've seen countless. That's why the loop is there; to prevent that kind of thing down the road. and in case they get rotozipped, tho there are box guards to prevent that.

 

[GoldDigger]

Especially handy to have where you have to pull the can out to get to the junction box!

mobile

 

[iwire]

It's a service loop and there should be zero issue with leaving one. It's actually a more quality install imo.

I agree 100%.

and they dont violate 334.30.

I strongly disagree here.

If there is a staple within 12" of the box, it's good. there is nothing that says the wire must be pulled like a banjo string between that staple and the box, it's just usually done that way with NM because it looks a bit neater.

IMO the intent of the code section is 'pulled like a banjo string between that staple and the box'.

If I read it your way I could hang a 250' loop of cable between the staple and the box.

how many electrical boxes have you seen where the conductors are impossibly short, and pigtailing every thing results in an ugly mess of wirenuts that are smashed back in the box?

A lot and that is why I think leaving slack is a good idea, just not really within the NEC requirements.

I would hope that if the loop is made in a way that keeps it from being damaged by the drywallers that the inspector would exercise this part of 90.4

permit alternative methods where it is assured that equivalent objectives can be achieved

Or even easier, just not notice it.

In my area they are pretty loose with that 12" rule as long as the cable is safe.

 

[ActionDave]

For installs where the cable enters a pan box, we let that slide because of roto-zips. However when they do it next to a recessed can, there is no danger to the conductors.

If we are talking about romexes going into a recessed can then I would give the guys a break. When I was wiring houses I would strip and twist my romexes outside the box before making them in the can j box. It was so much easier. It meant that there was some extra slack looping up after the staple, but it never killed anyone or started a fire.

It's one thing to enforce the rules to make sure things are safe, it's quite another to enforce one's idea of good taste.

 

[JFletcher]

I agree 100%.



I strongly disagree here.




IMO the intent of the code section is 'pulled like a banjo string between that staple and the box'.

If I read it your way I could hang a 250' loop of cable between the staple and the box.



A lot and that is why I think leaving slack is a good idea, just not really within the NEC requirements.

I would hope that if the loop is made in a way that keeps it from being damaged by the drywallers that the inspector would exercise this part of 90.4



Or even easier, just not notice it.

In my area they are pretty loose with that 12" rule as long as the cable is safe.

334.30 does not mention wire distance, just within 12" of the box (something else is 8" within single gang boxes w/o clamps tho I forget the section). I get what you are saying about the huge (250') service loop; Im sure there are other sections that would prevent that. Ive never seen anyone leave more than a short S-loop in NM, for practicality and monetary reasons.

300.14 is the section that deals with conductor length in a box, and having to splice everything blows actual or "real world" box fill, even tho wirenuts and splices arent counted by the NEC toward that. I thought there was another section that allowed you to bypass 300.14 if the conductor length was svsilsblr outside the box, tho I cant find it; it would only work with NM anyway

eta: maybe I am thinking of 334.30(C) with devices w/o outlet boxes (like in trailers). Those require a loop to permit replacement. That NM must be looped in one situation but forbidden in another makes zero sense to me. We are also allowed to fish walls (no securing) and one could run a 1000' of NM thru stud holes horizontally without staple number one.

 

[Dennis Alwon]

334.30 does not mention wire distance, just within 12" of the box (something else is 8" within single gang boxes w/o clamps tho I forget the section). I get what you are saying about the huge (250') service loop; Im sure there are other sections that would prevent that. Ive never seen anyone leave more than a short S-loop in NM, for practicality and monetary reasons.

300.14 is the section that deals with conductor length in a box, and having to splice everything blows actual or "real world" box fill, even tho wirenuts and splices arent counted by the NEC toward that. I thought there was another section that allowed you to bypass 300.14 if the conductor length was svsilsblr outside the box, tho I cant find it; it would only work with NM anyway

eta: maybe I am thinking of 334.30(C) with devices w/o outlet boxes (like in trailers). Those require a loop to permit replacement. That NM must be looped in one situation but forbidden in another makes zero sense to me. We are also allowed to fish walls (no securing) and one could run a 1000' of NM thru stud holes horizontally without staple number one.

In my opinion, it does mention wire distance. Take out all the verbiage that is not relevant to this situation... The cable must be supported within twelve inches of the box. Now if you can honestly say the cable is supported within 12" with 36" of cable in a loop then I believe you are incorrect and pushing the wording to suit the situation.

Nonmetallic-sheathed
cable shall be supported and secured by staples
within 300 mm (12 in.) of every outlet box,

 

[JFletcher]

In my opinion, it does mention wire distance. Take out all the verbiage that is not relevant to this situation... The cable must be supported within twelve inches of the box. Now if you can honestly say the cable is supported within 12" with 36" of cable in a loop then I believe you are incorrect and pushing the wording to suit the situation.

Pushing the wording does not equate to violating the wording. If you were an inspector, and the NM staple was 11.5" from the box, vertically, are you going to red-tag it because the hypoteneuse of the distance of the cable from the staple to the box opening is 12.4"? That is basically a banjo string.

If the staple were 3" from the box and there was an 8" S loop, would that be kosher? The wire is stapled within 12" of the box and so is the total free run.

this is another section of the code that I think is incredibly poorly worded and contradictory to other sections.

 

[al hildenbrand]

Dennis,

Nonmetallic-sheathed
cable shall be supported and secured by staples
within 300 mm (12 in.) of every outlet box,

Your edit of the language still doesn't say what you want (intend) it to say. The measurement is simply NOT referenced to anything except the staple and the box.

As much as I read, in this thread, the "intention" is to measure only along the sheath of the cable between the staple and the box, the actual enforceable language of the published NEC does not say that.

This, then, is where those in favor of the "intention" say the words don't matter, do what I mean.

 

[Dennis Alwon]

Pushing the wording does not equate to violating the wording. If you were an inspector, and the NM staple was 11.5" from the box, vertically, are you going to red-tag it because the hypoteneuse of the distance of the cable from the staple to the box opening is 12.4"? That is basically a banjo string..

Let's not talk 1/2" or whether I would pass it. I am talking code rules.

If the staple were 3" from the box and there was an 8" S loop, would that be kosher? The wire is stapled within 12" of the box and so is the total free run.

Yes, it would be kosher because there is a staple and less than 12" of wire from the fixture. Nothing says the wire must be flat. Ever hook up a can in a ceiling with 24" on center trusses? It is difficult to get 12" but you can even if the staple is measure at an angle... It is free wire that we are dealing with.

this is another section of the code that I think is incredibly poorly worded and contradictory to other sections.

I disagree... You are making it more difficult than it is, IMO.. Seriously do you really think the intent is to have 3' of wire flopping around with a staple 6" away from the box. That makes no sense at all.


Obviously, we will have to agree to disagree. Back to the op-- I am not sure I would worry about those 18" if they are protected and not likely to get pull down and possibly hit by a nail or something. More importantly, I would tell the installer that their interpretation is incorrect but if they could give me a valid reason why I should allow more than 12" free than I would probably say ok. A valid reason would be if the can design was such that 12" wouldn't work if one had to access the jb at a later date.

 

[JFletcher]

Let's not talk 1/2" or whether I would pass it. I am talking code rules.

Yes, it would be kosher because there is a staple and less than 12" of wire from the fixture. Nothing says the wire must be flat. Ever hook up a can in a ceiling with 24" on center trusses? It is difficult to get 12" but you can even if the staple is measure at an angle... It is free wire that we are dealing with.

I disagree... You are making it more difficult than it is, IMO.. Seriously do you really think the intent is to have 3' of wire flopping around with a staple 6" away from the box. That makes no sense at all.


Obviously, we will have to agree to disagree. Back to the op-- I am not sure I would worry about those 18" if they are protected and not likely to get pull down and possibly hit by a nail or something. More importantly, I would tell the installer that their interpretation is incorrect but if they could give me a valid reason why I should allow more than 12" free than I would probably say ok. A valid reason would be if the can design was such that 12" wouldn't work if one had to access the jb at a later date.

So, I'll just put my NM staple as close to the box as possible (say, 4") and put the remainder of that 12" (which would be 8") as a service loop. Have we really accomplished anything there?

I do bring up that 1/2" and you as inspector because we have to draw the line somewhere. As I read 334.30, I dont see how I could fail a box with a staple within 12" of it. The Code doesnt specify wire distance between that staple and the box, or total wire distance between the staple and that box, etc. Im not making it more difficult. It literally says there must be a staple or other means within 12" of the box. It does NOT say the wire length between said staple and box must be 12" or less.

eta: if I worked for you, would you reprimand or fire me for putting in service loops?

 

[Dennis Alwon]

No, I wouldn't fire you but I would tell you to make sure there isn't more than 12" of cable between the staple and the box. Why? because you will probably fail in some areas around here.


I am sorry but I cannot understand your thinking on this. If you allow this in a ceiling for a can you will have to allow a staple 6" from a switch box with 4' of cable looped. Now there are 3 cables in that box... will you allow all 3 cables with a 4' loop?

 

[Dennis Alwon]

I am using the 4' because nm must be stapled every 4'-- so the rule for a staple 12" from a box is assinine if 4' is allow to be looped.

 

[al hildenbrand]

If you allow this in a ceiling for a can you will have to allow a staple 6" from a switch box with 4' of cable looped. Now there are 3 cables in that box... will you allow all 3 cables with a 4' loop?

And yet if the NM is fished there is absolutely NO limit on the unsupported length between the last support and the box. Hmmmmm. What's different? A clamp on the NM sheath at the box.

If your slippery slope to 3 cables with 4' loops in open construction were truly an issue, it couldn't be done in a fished situation either. In my opinion.

 

[Dennis Alwon]

And yet if the NM is fished there is absolutely NO limit on the unsupported length between the last support and the box. Hmmmmm. What's different? A clamp on the NM sheath at the box.

If your slippery slope to 3 cables with 4' loops in open construction were truly an issue, it couldn't be done in a fished situation either. In my opinion.

Totally disagree. There is much more damage that can be done to a cable unsupported at those lengths when the sheetrock is not installed. You can't seriously compare the two situations.