Can I attach NM to edge of joists in an inaccessible location?

[Flicker]

Hello:

I have an apartment building where I periodically run new circuits to add a washer, dryer and dishwasher.

I have been running the new NM in the crawl space and I have been attaching the NM to the bottom edge of the joists.

I just read in 334.15(C) Exposed Work:

(In Unfinished Basements and Crawlspaces. "Where cable is run at angles with joists in unfinished basements and crawl spaces, it shall be permissible to secure cables not smaller than two 6 AWG or three 8 AWG conductors directly to the lower edges of the joists. Smaller cables shall be run either through bored holes in joists or on running boards."

The crawl space is quite low at only about 3 feet high. And also, the only access to the crawl is through a screened small access hole in the foundation which only a maintenance person would choose to squeeze into.

I was wondering what 334.15 (c) was attempting to protect against?

I have read about the risk of someone using the NM as a clothes line or it receiving an impact, but in my situation, there is not enough height or access for either of those things to happen.

When I run these circuits, I would prefer not to have to install running boards, or have to drill holes in the joists along an indirect route since running the NM the most direct route is physically painful enough as I have to crawl on my stomach from often a distant access point to where the wire needs to go.

Does the code allow attaching on the ends of the joists in such a low and hard to reach location?

If not, what is the code trying to protect against in this situation?

Thanks.

 

[tkb]

So 334.15(B) says that you can't run you NM cable on the underside of the joists in a crawlspaces and you want to know if it applies to you?

Yes it does. It is a violation.

The reason why it is a requirement is, it's in the code.

 

[Flicker]

So 334.15(B) says that you can't run you NM cable on the underside of the joists in a crawlspaces and you want to know if it applies to you?

Yes it does. It is a violation.

The reason why it is a requirement is, it's in the code.

Since it is possible that I am misinterpreting the code or the code may have exceptions, I wanted to confirm that it applies in my situation.

Especially, since I do not see what the increased risk is in such a small space.

 

[Ponchik]

3' of crawl space?? That is a REALLY nice crawl space.

Yes you would be in violation if you install it without the running boards or without the holes.

IMO, I don't see the harm in running it underneath the joist, but it is what it is.

 

[JFletcher]

Is Washington state under the 2012 International Residential Code? In VA, we have this:

E3802.4 In unfinished basements.
Where Type SE or NM cable is run at angles with joists in unfinished basements, cable assemblies containing two or more conductors of sizes 6 AWG and larger and assemblies containing three or more conductors of sizes 8 AWG and larger shall not require additional protection where attached directly to the bottom of the joists. Smaller cables shall be run either through bored holes in joists or on running boards. Type NM or SE cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with Table E3802.1. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the where cable enters the raceway. The sheath of the Type NM or SE cable shall extend through the conduit or tubing and into the outlet or device box not less than 1/4 inch (6.4 mm). The cable shall be secured within 12 inches (305 mm) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor complying with Section E3908.13.

Here, crawlspaces are exempt from 335.15(C). May be the same there; you'll have to check.

eta: If the joists are open (not insulated), I find it easier and neater to drill holes thru the joists than carry around pocket full of staples, having to hammer them in laying on my back, and getting junk in my eyes, or disturbing the ever present mole/spider crickets who jump everywhere when approached/scared. With a sharp bit and good drill, how long does it take to drill 30 or so 7/8" holes anyway?

Second eta: how are other cables run in the crawlspace? If they are routinely stapled perpendicular under joists, chances are it's okay.

 

[user 100]

Since it is possible that I am misinterpreting the code or the code may have exceptions, I wanted to confirm that it applies in my situation.

Especially, since I do not see what the increased risk is in such a small space.

The risk ( dog getting in there somehow and tugging on it with his teeth, clumsy guy gripping it and pulling it loose while trying to work on the plumbing if it too is routed under there) may be infinitely small but it's still there- just about the only remotely plausible scenarios, however ridiculous. Just wait until it comes up about whether or not this is damp loc thus prohibiting nm entirely. (I don't think it is btw)

I agree w/ the others about 334-Just install the running boards and be done with it.

 

[Flicker]

Here, crawlspaces are exempt from 335.15(C). May be the same there; you'll have to check.

Is anyone aware of Pierce County, Washington exempting crawl spaces?

eta: If the joists are open (not insulated), I find it easier and neater to drill holes thru the joists than carry around pocket full of staples, having to hammer them in laying on my back, and getting junk in my eyes, or disturbing the ever present mole/spider crickets who jump everywhere when approached/scared. With a sharp bit and good drill, how long does it take to drill 30 or so 7/8" holes anyway?

Second eta: how are other cables run in the crawlspace? If they are routinely stapled perpendicular under joists, chances are it's okay.

I agree but the joists are insulated and all of the existing wiring was original before insulation and when the install could be done from above without any crawling so it is not on the bottom of the joists.

This may sound nuts to some of you but one compromise solution appears to be that I could run the 20a, 20a, and 30a circuits on 8/3, 8/3 and 8/3 w ground (for the dryer) and then it appears that I am allowed attached to the bottom of the joists.

I did the math and the extra wire costs will be about $55 and that very well may be worth it to avoid the extra crawling.

Does anyone see a problem with running the 8/3?

 

[JFletcher]

Is anyone aware of Pierce County, Washington exempting crawl spaces?



I agree but the joists are insulated and all of the existing wiring was original before insulation and when the install could be done from above without any crawling so it is not on the bottom of the joists.

This may sound nuts to some of you but one compromise solution appears to be that I could run the 20a, 20a, and 30a circuits on 8/3, 8/3 and 8/3 w ground (for the dryer) and then it appears that I am allowed attached to the bottom of the joists.

I did the math and the extra wire costs will be about $55 and that very well may be worth it to avoid the extra crawling.

Does anyone see a problem with running the 8/3?

I'd find out first what code WA is under. I know there are several active members here from WA state who can probably answer that.

You could also get a helper and some 1x2s to install running boards. there cant be much distance involved if you're talking about just a $55 increase of wire cost running 8ga vs 12/12/10. Buy $15 worth of lumber, pay some kid $20 for the half hour to install it, you come out ahead over buying big wire which will have to be pigtailed (more time involved for you in a tight space).

For $55 you could also buy some really awesome kneepads which will be with you on future jobs.

eta: I found this for you:

http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_38_par013.htm

"E3802.4 In unfinished basements and crawl spaces.
Where type NM or SE cable is run at angles with joists in unfinished basements and crawl spaces, cable assemblies containing two or more conductors of sizes 6 AWG and larger and assemblies containing three or more conductors of sizes 8 AWG and larger shall not require additional protection where attached directly to the bottom of the joists. Smaller cables shall be run either through bored holes in joists or on running boards. Type NM or SE cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with Table E3802.1. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point where the cable enters the raceway. The sheath of the Type NM or SE cable shall extend through the conduit or tubing and into the outlet or device box not less than 1/4 inch (6.4 mm). The cable shall be secured within 12 inches (305 mm) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor complying with Section E3908.13.

So you have to bore holes, use running boards, or larger cable. You could also go parallel to the joists out to the band board (or center support beam), go across that, and back to the washer, dryer, etc parallel to a joist and be compliant but that will not be a straight shot - more crawling

 

[user 100]

I'd find out first what code WA is under. I know there are several active members here from WA state who can probably answer that.

You could also get a helper and some 1x2s to install running boards. there cant be much distance involved if you're talking about just a $55 increase of wire cost running 8ga vs 12/12/10. Buy $15 worth of lumber, pay some kid $20 for the half hour to install it, you come out ahead over buying big wire which will have to be pigtailed (more time involved for you in a tight space).

X2- Nothing wrong with Flickers plan, but just something "ugh" about using #8 for those amperages in a residence.

 

[Sierrasparky]

Is anyone aware of Pierce County, Washington exempting crawl spaces?



I agree but the joists are insulated and all of the existing wiring was original before insulation and when the install could be done from above without any crawling so it is not on the bottom of the joists.

This may sound nuts to some of you but one compromise solution appears to be that I could run the 20a, 20a, and 30a circuits on 8/3, 8/3 and 8/3 w ground (for the dryer) and then it appears that I am allowed attached to the bottom of the joists.

I did the math and the extra wire costs will be about $55 and that very well may be worth it to avoid the extra crawling.

Does anyone see a problem with running the 8/3?

Yes there could be issue with ground wire size.

 

[Dennis Alwon]

NC also has an amendment that allows us to staple to the bottom of joist in crawl spaces. However I have wired for many years and we always squared off the wires. There is usually a sill plate, beam in the middle or something to nail to that would satisfy code. It will use more wire for sure but it is easier, imo than installing running boards.

 

[ActionDave]

Can somebody please find something for CMPs to do and still feel important?

Can somebody please find something for CMPs to do and still feel important?

Look at what we are talking about to try and comply with a recent code change! We have fifty plus years of safe installations of romex in crawl spaces. Then, all of a sudden, Poof!, we need a change.

What's even worse is the justification for the code change:
Safety? No
Failures? No
It was to bring consistency in the code language between basements and crawl spaces.

What's even worse than that is the instigator of the change.

 

[JFletcher]

Look at what we are talking about to try and comply with a recent code change! We have fifty plus years of safe installations of romex in crawl spaces. Then, all of a sudden, Poof!, we need a change.

What's even worse is the justification for the code change:
Safety? No
Failures? No
It was to bring consistency in the code language between basements and crawl spaces.

What's even worse than that is the instigator of the change.

How recent a code change for small cables in crawlspaces not being able to be stapled under joists perpendicular? My 08 NEC has that rule.

(eta: seems that crawlspaces were added in the 08 cycle)

Also, what/who brought that change, and why? wouldnt it have been simpler to define the differences between a crawlspace and basement?

 

[Dennis Alwon]

Look at what we are talking about to try and comply with a recent code change! We have fifty plus years of safe installations of romex in crawl spaces. Then, all of a sudden, Poof!, we need a change.

What's even worse is the justification for the code change:
Safety? No
Failures? No
It was to bring consistency in the code language between basements and crawl spaces.

What's even worse than that is the instigator of the change.

I think one of our members wrote this change- I believe it was Ryan

 

[kwired]

The risk ( dog getting in there somehow and tugging on it with his teeth, clumsy guy gripping it and pulling it loose while trying to work on the plumbing if it too is routed under there) may be infinitely small but it's still there- just about the only remotely plausible scenarios, however ridiculous. Just wait until it comes up about whether or not this is damp loc thus prohibiting nm entirely. (I don't think it is btw)

I agree w/ the others about 334-Just install the running boards and be done with it.

But none of those conditions you mentioned will ever be able to happen if we drilled holes through those framing members and installed those cables 1-1/4 to 2 inches higher from the crawlspace floor.

This is a rule I admit to ignore at times, especially in a crawlspace that already had wiring attached to bottom of framing members.

 

[jap]

But none of those conditions you mentioned will ever be able to happen if we drilled holes through those framing members and installed those cables 1-1/4 to 2 inches higher from the crawlspace floor.

This is a rule I admit to ignore at times, especially in a crawlspace that already had wiring attached to bottom of framing members.

I wouldn't say I ignore it but the thought of drilling holes in perfectly good floorjoists don't compute for me.
I have unknowingly did the same thing as the OP and didn't know it was a violation until I seen it in the code sometime later, Not that I'd go back and change it.
The only reason I could come up with for myself for this rule was that the tension that would be needed to keep the smaller cable tight up against the underside of the floorjoists might somehow affect the cable over time, otherwise, to me none of the other reasons stated don't make a bit of sense to me.

JAP>

 

[jap]

And furthermore , my dog is dumb. Once he got the crawl hole cover off with my phillip screwdriver he'd jump up and bite the wiring regardless of whether it was stapled to the bottom or run through bored holes.

JAP>

 

[jumper]

And furthermore , my dog is dumb. Once he got the crawl hole cover off with my phillip screwdriver he'd jump up and bite the wiring regardless of whether it was stapled to the bottom or run through bored holes.

JAP>

Let's be real here, if the dog is smart enough to get the cover off with a screwdriver, there is no reason to believe he would be stupid enough to bite the wires.

 

[jap]

You don't know my dog.

JAP>

 

[ActionDave]

I think one of our members wrote this change- I believe it was Ryan

It was. Silly, irritating code change.