Anyone heard the the affect that spray foam has on romex?
Have a customer that had her whole walk in attic sprayed full of it. Romex cable, etc...

Thanks...

NEMA issues a "white paper" some time ago on the topic. The short version? No need to change anything .... the foam will not harm the cable, and derating remains the same.

Ok. Thanks for info..

The only time it becomes an issue is if a couple cables are bundled in the foam or going through a penetration sealed with foam. You treat it like a raceway at that point. (you derate)
334.80

I've seen PVC react with foam but AFAIK it affects the foam rather than the PVC. The end result is that both stick together. Probably plasticisers from the PVC soften the foam and make it sticky. That's why you should never store vintage equipment in its original box without separating any cords from the foam. Now that I think of it the RF cable of the Commodore C-16 I sold some time ago did have melted spots from the packaging!

Apparently Canada had a bad run with spray foam and romex about 10 years ago.. it was destroying the jacket on the romex.

http://safetyauthority.ca/sites/def...%20Polyurethane%20Spray%20Form%20Ins.pdf

There were some issues with foam related to the chemical contained in the product that I recall from time past.

NM jacket becoming soft and 'melting', similar to what happens with a non-latex base primer used in fire restoration jobs.

Time to check out Dougs link

Yes but i am confused Greg....

334.80 forbids 310.15 A 2 EX. & requires 310.15 B 3>>>



338.80 in part reads>


Most of our installs are required to have fire caulk between floors and/or units. These holes might be 4-5" in length, not 24" , so can i take it the 24" is relevant here?

I ask , because local code 'lore' seems to think otherwise, or perhaps said firecaulk does not work well for mutli-wires?


~S~

But they are talking about mechanical strain, not thermal damage

~S~

Sparky, I agree the fairly new 334.80 does not really make a lot of sense.
The NEMA, study often cited, even makes it more confusing since it really just refers to the foam not damaging the jacket. I see nothing that indicates short sections in foam would overheat.

http://gfretwell.com/electrical/NEMA%20Romex%20in%20foam%20study.pdf

But rulz is rulz.

Greg:
Insulation is usually not installed until after 'rough' electrical approval, followed by a framing approval. As the ECs are long gone, after completion of rough wiring, who is to 'see' the insulation job. Spray foam in this discussion.

The Ecs usually are not back on site until trim out time. The inspectors are not back till final.

I understand the inspection issue but if you know they are spraying foam, you will see the violation coming at the rough. Since the holes have to be draft stopped, those will be obvious. I suppose the question is what would constitute "spacing" in these penetrations? If you just pushed the RX apart and jammed something in between them,(Romex jacket, stick of wood or whatever)is that spacing?
Certainly if the EC had collected some pieces of duct board, left over from the HVAC guys and jammed some in between RX in the holes, he has met the intent of the code assuming there is any wiggle room at all.
You should be drilling more holes anyway if you have that much RX in one hole. I guess the issue comes up most right above the panel where you have a whole bunch of cables in the same spot. That has always been troubling, one way or the other. Again, as long as each cable has some space around it when they pump in the foam, no problem as I see it. It is only when they are "installed without maintaining spacing" that 334.80 comes in.

Gentlemen,

338.40 applies to over 24"

yes/no....

~S~

Also, 312.5(C)EX. is commonly utilized , especially in all those prefabs we pass by everyday

Juxtapose to 338.40 please.....if it isolated from foam via pipe ...etc....

~S~

338.40?

I don't have that one

334.80, pardon my dyslexia Greg....:( ~S~

334.80 does not say 24" anywhere. The only reference to 310.15 is to the table and the exception that does not apply.

Scenario then....

312.5(C) EX , 2---2" sch 40 pipes from basement panel , run up to but not penetrating ceiling, meets all of provisions a-g

2 larger holes are drilled , about a dozen rx conductors each hole, down into pipes/panel.

These bored holes go thru 2x4 plate & decking , for a total of 4"

The ONLY place where they can be seen as 'bundled' is withing this 4" passage

This is the foamed

What code is violated please?

~S~

~s~
Based on what you stated, IMHO.....no issues

Unfortunately 334.80 does not specify a distance. If they are bundled in a bored hole in wood and foamed in, that is a violation.

Do I agree? No ... but that is the way they wrote it and I have been in a number of inspector meetings who agree it is what they say, as stupid as it sounds. I suppose you can 90.4 it.
I have not looked at the proposals since but it would be interesting to see what NFPA says.

I have been digging through dusty ROPs all evening and I came up with 3 that seem appropriate to what NFPA is thinking.

This is the initial 2005 proposal substantiation.




Our old buddy Mike Holt suggested that they should just drop the whole paragraph for the 2008 pointing out these are only bundled for 3-4" in the foam (with a lot of other verbiage) He got this response



Frederick Hartwell proposed it again for the 2011 and got this



Nobody addressed it for the 2014

I am still trying to track down that report they used to justify the original 2005 change but the NFPA web site is miserable. Putting something in their search bar does not seem to affect the 30 pages of hits that it responds with.

How so?


334.80 will end up @ Table 310.15(B)(3)(a) , where under 24" is not a problem

~S~

Table 310.15(B)(3)(a) does not mention "24" or any other length. 334.80 refers to the table not the article.
If you read the comments in the ROP it is clear NFPA is concerned about that 3" section that is buried in foam and they say it does act differently than wires in a pipe.
I would still like to see the study that prompted the change in 2005 but I have not found it yet.

This is a first for me then Greg

Since when has the NEC required a table w/o requiring the applicable codes to it ?

~S~

I suppose the real answer is in the style manual somewhere but it seems clear NFPA is talking about >9 90c CC conductors in NM jackets in 3" of foam in a bored hole, in wood, just based on what CMP7 says in the ROPs

With all due respect Greg, In this situation a code ref for derating doesn't rate the privilege of a 90.4, it's far to cut/dry

Nor can i (et all EC's) be a competitive biz based on some study being batted around the CMP's.

Further, why would it be necessary for any CMP to reinvent the wheel foisting some 'study' when other countries /electrical codes (most are IEC spin offs) have already had a handle on the issue for decades?

IMHO, we have a system of deaf copperholic based rationale going on here....

~S~

I am just an old inspector, not an umpire.
I am not sure how I would deal with this in the field but I doubt it would come up. That is a lot of wire to get in a hole.
If you are taking out that big a hole, why not just take out a big slice (the structure was already away), lace out the cables on a wide running board and let them foam that in.

I'm an old EC that looks to my AHJ's for solid answers Greg.

In past cases like this it's considered the job (tax subsidized at that) of the NEC ,CMP.s ect to provide the tools needed for field decisions.

We have ,in the past, asked for formal interpretations from Batterymarch park.

Were you and i toe/toe on the job, i'm sure i'd suggest it.

In fact, just this exchange alone should inspire us toward such a goal, if you're game...:)

That said , the best ahj's look for ways to pass a job vs. failing it, so i appreciate your 'big slice' suggestion, and would like to up the ante' with a sleeve....to forgo any mass burial of nm in foam...>>>

I refer you to Chap 9 tables....where i can stuff as many nm's as i can fit in a piece of sch 40....



~S~

I am just reading what CMP 7 has said about the second paragraph of 334.80.
Your AHJ can read it any way they want and you are right, that is what matters. Just be aware, the next inspector who shows up may have actually read the ROP.
My wife is running into this where she works with the life safety officer. Things that were fine for 20 years suddenly became a violation when they went from county code enforcement to city code enforcement (different AHJ) with no changes to the language of the code.

I'm running into the same situation where I'm trying to upgrade a century-old installation but it appears that the AHJ would rather that I just leave it as a firetrap since I won't tear out structure that has served perfectly since the late 1800's...but doesn't meet the strict letter of this years' Code.

I've had the foam shoe on the other hoof as well....

I went a few rounds with an archy and his lighting lady here , who wished to have me install 12 cans in a vaulted ceiling, to be spray foamed.

They all backed up to a shingled roof as well .....

My concern was captive heat , from lamps , not the wiring.

There was a flurry of paperwork and manufacturers specs, re> can ,shingle & foam, bantered back/forth, but nothing to directly advocate the install of each in close proximity.

In my view, this should have been considered a listed assembly, or had a field rep visit, etc....

One can't be too careful as an EC, because almost everyone around an EC has either disclaimers(AIA 401 for archy's) or sovereign immunity (state officials)

I can count 12 'dots' in said roof when it snows here....:(

~Sparky, EC, still at large~

When I actually read the ROP comments it does look like they are saying embedding wire in foam degrades the ability to shed heat far more than just being in a cable jacket, a pipe or simply bundled together. This actually seemed to go back to an SE issue that came up where a bunch of them went through one hole and burned up. Granted 310.15(B)(6) might allow an SE to be overloaded to start with. (like 100a in a 4 ga).

I would like to have heard some of the arguments on your "can" fight.
"IC" does stand for insulation contact.
I suspect the first indication of a problem would be blinking lights as the thermal cycled. What that would be doing to the foam is another issue. I agree with you. Being slap up against fiberglass is not much of a problem but plastic foam can go right up.
I guess when we are all LEDs we won't care about luminaire heat that much ... as long as it is not an Edison base.

I'm sure their concerns have merit Greg, and i've read my share of domestic studies.

A few points about 'studies' would be, many are inconclusive, as science is repeatable , in the consideration of captive heat, it would be applicable to the end users.

For Ex, labs studies bundle conductors, and push them to 100/125% of rated capacity. Show me a resi-reality where this happens?

2ndly, I'm apt to ask who's dime the 'study' is on. Face it, we can ring up pro/con studies on anything.

Last but not least, I find the NEC to always play the isolative card. The issue of CCC's captive heat via insulation has been done by other systems for over a generation now Start here

The NEC being dwarfed by the IEC it (in part) it acknowledges should rightly be looking up their findings, not ignoring them, lest they've subvertly choosen to go the 'global warming' route here.







My queries about IC vs. spray foam resulted in a tirade between archy,foamer,roofer,lighting provider......

A lot of information was exchanged, much with conflicting 110.3(b) , for ex the lighting manufacturer's 'IC' ratings did not address spray foam immersion , but has the 'call a licensed spark' disclaimer

The spray foamer followed suit, with the spectre of differences in open/closed cell. This also has the carpenters involved as to where the captive 14%? (+-) moisture of kiln dried construct ends up.

We're talking more than just our trade here, i've been party to some reno's firehosing spray foam over antiquated installs of EVERY trade.

Last are LED's and the green machine. As i live in a state so blue it can be seen from space i've no choice but to bow down to our state dept of energy nazi's

Where this canard of LED's being non heat or low heat element started i do not know, but checking with the recent updates in 410 ,it appears at least that CMP viewed them correctly.

Just the heat sinks alone on some of the LED outlighting products should evidence this enough for the casual viewer...

The aforementioned lighting lady tried to foist this on me as well, as her offering were LED. As an aside, i've outfitted my entire home to LED, still get the 'you use too much juice' notices from our lovely energy monitors here

They're great for starting the wood stove....:)

~S~

I see at the end of February they sent out a revised bulletin looks the same to me

http://www.safetyauthority.ca/alert...nsulation-non-metallic-sheathed-cables-0