Question on a 2011 handbook Exhibit on Crawlspace cables

[Dennis Alwon]

Thanks to Speedskater, I found the thread I deleted in a cached version. I am now attempting to repost the thread.

Would somebody mind reading page 297 of the 2011 handbook and explain to me what this means as far as stapling cables to the bottoms of floor joists in a crawl space? EXHIBIT 300.2

iT seems to me they are prohibiting stapling to the bottoms of floor joists generally. only if there is a guard strip next to them or they are on a board. did something seriously change things?

Same as it was in 2008 code 334.15 (C)

that explains it. i dont read anything cept Handbooks and Comic books. if it aint got pictures, then forget it.


So, now that we have established that it is wrong to staple 12-2 to bottoms of floor joists, IS ANYBODY OUT THERE ACTUALLY BEEN COMPLYING WITH THIS?
This sounds like the biggest PANT LOAD i've ever heard of. i have not stopped and i have never been called on it, ever. have you? i think this is just absolutely absurd. It just can't be that the only reason i havent been nailed on this is because not even one single inspector went under the house??? WHAT possible reason could this actually serve? Yes another code rule that has no concept of reality. Really? drill holes in the floor joists? you KNOW that AINT gonna happen. sorry, i know nobody here wrote the codebook.

(Crawl spaces) was added in 2008 code

Does anyone on here know what caused the codemakers to change this. Where is the hazard in this? Rats doing pullups?

Mike Holt wrote the proposal:

7-58 Log #2399 NEC-P07 Final Action: Accept
(334.15)
__________________________________________________ __________
Submitter: Mike Holt, Mike Holt Enterprises
Recommendation: Revise text to read:
334.15 Exposed Work. In exposed work, except as provided in 300.11(A), cable shall be installed as specified in 334.15(A) through (C).
(A) Remain unchanged.
(B) Remain unchanged.
(C) In Unfinished Basements and Crawl Spaces . Where cable is run at angels 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. NM cable used on a wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing. Conduit or tubing shall utilize a nonmetallic bushing or adapter at the point the cable enters the raceway. Metal conduit and tubings and metal outlet boxes shall be grounded.
Substantiation: The code differentiates between an unfinished basement in different areas of the code, such as in 210.8(A). This code section, however, does not give any direction as to the requirements for a crawl space. Because the same dangers exist in both unfinished basements and crawl spaces, this subsection should be changed to include both locations.
Panel Meeting Action: Accept
Number Eligible to Vote: 14
Ballot Results: Affirmative: 13 Negative: 1
Explanation of Negative:
BROWN, H.: We disagree with the panel action to accept this proposal.
This proposal will allow for cables not smaller than two 6 AWG or three 8 AWG conductors to become fastened directly to the lower edges of joists (in a crawl space). A “crawl space” is not defined in the code. Without placing “height restrictions” or defining a “crawl space” this provision will quickly become a safety issue.
For example: A crawl space may exist beneath a building on a conventional foundation. An individual would have to navigate under surface mounted wiring, (possibly in a “tight” space), while attempting to move around under the building. The individual could “snag” the wiring, and pull it away from its fastening. “Tight spaces” are already an impediment to performing work. Surface mounted cables should not be located in these types of spaces. Without defining “crawl space”, there are no guidelines or restrictions for allowing a lessening of the current rules. The existing installation requirements
provide that the cables must pass through bored holes. This has been an accepted practice for many years, as it provides for a safe installation of the product. Are we becoming too lazy to bore holes to protect our wiring method? Let’s continue to give the consumer, the service technicians, and everyone else (pest control, etc.) a safe and efficient electrical installation.

VA amended this and deleted the requirement for crawl spaces.

 

[Dennis Alwon]

Here is the thread where Ryan, a Mike Holt moderator takes responsibility :grin: for the proposal that was accepted. Post #18

Here is the raceway by Arlington.

 

[LarryFine]

Here is the raceway by Arlington.

Using that method can certainly cause one to use a lot more cable, or use a lot of the trough.

It's enough to make one forgo most under-floor wiring and bore studs more, or run overhead more.

 

[Dennis Alwon]

Using that method can certainly cause one to use a lot more cable, or use a lot of the trough.

It's enough to make one forgo most under-floor wiring and bore studs more, or run overhead more.

I agree. It isn't cheap either. Fortunately your state and mine has amended this section.

 

[Bullcub145]

Makes you wonder how much companies like arlington are enjoying this code update. It seems that they are the only people who like this update.

 

[LarryFine]

Makes you wonder how much companies like arlington are enjoying this code update. It seems that they are the only people who like this update.

Horrors! Not the Kenny-clamp conspiracy again! :grin:

 

[fisherelectric]

Where can I find the amendments Va has made to the 2008 NEC?

 

[Dennis Alwon]

Where can I find the amendments Va has made to the 2008 NEC?

I believe this is the document. Check out page 68 at the bottom--- crawl spaces is omitted.

68. Change Section E3802.4 to read:
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. NM 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 NM or SE cable sheath 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.

 

[renosteinke]

Looks like this is something sure to be revisited in 2014.

The justification that was always given- even in NFPA documents- for requiring firring strips was that someone might use the cables to hange clothes on. That's kind of hard to do in a crawl space.

The artwork in the handbook seems to conflict with the code text. The text refers to 'where nails and screws are likely to penetrate.' I am having trouble imagining any situation where nails and screws would be driven through the 'side edges' of firring strips. IMO, the cable is better protected by being closer to the strips- not farther away. (For example, in an attic it's a lot harder to step on the cables if they're next to the wood).

The artwork also shows 'un-protected' cables stapled directly to the blocking.

The section discussed cable runs 'parallel' to framing members; the illustration shows cable that is parallel to the furring strips but at right angles to the framing members. Attaching cable directly to the bottom of the joist is not addressed.

While I am not opposed to drilling holes in framing members, I am leery of making it the 'default' method. Dimensional lumber, TJI's, and glulams all have specific requirements, and the 'correct' method for one is ofteh the exact method to avoid for another.

While on the topic, as for TJI's: I'd much rather see cable attached to the 'flange' than the web in parallel runs. The very act of pounding staples into the web is likely to destroy it- and we don't want to do that!

 

[iwire]

It has been posted already but people seem to overlook it.

Mike Holt put in the proposal, here is the substantiation.

Substantiation: The code differentiates between an unfinished basement in different areas of the code, such as in 210.8(A). This code section, however, does not give any direction as to the requirements for a crawl space. Because the same dangers exist in both unfinished basements and crawl spaces, this subsection should be changed to include both locations.

 

[roger]

It has been posted already but people seem to overlook it.

Mike Holt put in the proposal, here is the substantiation.

Substantiation: The code differentiates between an unfinished basement in different areas of the code, such as in 210.8(A). This code section, however, does not give any direction as to the requirements for a crawl space. Because the same dangers exist in both unfinished basements and crawl spaces, this subsection should be changed to include both locations.

I don't agree that the same dangers generally occur in crawl spaces and neither does the NC AHJ

Click here for NC's take on 334.15(C)



[FONT=Times New Roman,Times New Roman]Roger
[/FONT]

 

[iwire]

I don't agree that the same dangers generally occur in crawl spaces and neither does the NC AHJ

I think this along with Mike's proposal last code cycle to eliminate the uses of the grounded conductor as the grounding means at separate structures were both unneeded and simply done for the sake of conformity .... not safety. In both cases the substantiation did not present any evidence of real hazards, only imagined ones.

 

[roger]

In both cases the substantiation did not present any evidence of real hazards, only imagined ones.

Agreed.

Roger

 

[LarryFine]

While on the topic, as for TJI's: I'd much rather see cable attached to the 'flange' than the web in parallel runs. The very act of pounding staples into the web is likely to destroy it- and we don't want to do that!

Agreed, and that's what I do. Stackers do hang on the web okay, though.

 

[Dennis Alwon]

While on the topic, as for TJI's: I'd much rather see cable attached to the 'flange' than the web in parallel runs. The very act of pounding staples into the web is likely to destroy it- and we don't want to do that!

So how to you maintain 1 1/4" if you staple on the flange?

 

[stew]

agreed. and I also am of the opinion that the dangers are imagined or certainly worst case. I have been in hundreds of crawls and have never snagged a cable.

 

[renosteinke]

How to maintain 1-1/4" if you staple on the flange? Well, that's the problem, isn't it?

Or, at least ... I can see the issue making sense if the area is to be closed in. If, as in the case of your typical crawl space, there's no sense in closing in the joists - I believe it is simply silly to attempt to apply the 1-1/4" rule.

Indeed, is that not the very reason that the code language includes 'where nails or screws are likely to penetrate?'

I return to the artwork in the handbook, which seems to have no problem with cables secured to the bottom edges of the blocking. This is no less likely to interfere with 'closing in' than cables attached to the bottoms of the joists.

Likewise, the artwork has no issue with cables that are within the 1-1/4" of the imagined (future) enclosure- so long as those cables are at least an 1-1/4" from the furring. If the furring is there to protect the wire, the art makes no sense as you're not going to run a screw in the side edge of the furring. If the furring is there to attach drywall, the cables are still going to be just behind the drywall, completely unprotected from any errant screws.

Sometimes I wonder if the artwork is ever compared to the code it claims to illustrate. As drawn, the art makes no sense at all.

Off topic- a bit - .... best I can figure, in the case of TJI's, the only ways to run cables parallel to them is to screw mounts onto the flanges, 'bridge' the flanges and run the cables atop the bridging, or to 'weave' the cable through holes at 4-ft. intervals. If there was ever a place that needed a rule against staples, the web of a TJI is it! The installation of the staple (by hammer) will seriously weaken the web. (Each staple site would have to be considered as though it were a 2" hole) (Power driven staples MIGHT work acceptably).

Complying with the NEC, at the cost of bringing down the house, is not an option.

 

[Dennis Alwon]

Sure, in a crawl space that is a different issue but usually those joists are all over the house. If you have lots of homeruns running down one bay in a crawl space then that would be an issue. Using the stackers is great but those dang things are $.30 each.

 

[ActionDave]

I think this along with Mike's proposal last code cycle to eliminate the uses of the grounded conductor as the grounding means at separate structures were both unneeded and simply done for the sake of conformity .... not safety. In both cases the substantiation did not present any evidence of real hazards, only imagined ones.

And this is different from a long list of recent code changes, how?

 

[LarryFine]

So how to you maintain 1 1/4" if you staple on the flange?

On top of the bottom flange or on bottom of the top flange. That places the cable at least 1.5" from the nailing surface.