NM cable protection

[NEC Inspector]

Reallly foam insulation, has to all be covered. I did not know that. Doesn’t matter if it’s close cell or open cell.

Nope, and it doesn't matter if it's spray foam or sheet foam or what - it's pretty much all bad. Even normal Great Stuff out of the can for filling holes and gaps.

There are allegedly some foams that are treated and made safe to leave exposed, but I have never seen it aside from the "fire rated" foam in the can - it's not really fire rated, just rated to be exposed without an ignition barrier.

 

[AC\DC]

ooooooo—- I got to fix my garage lol

 

[jim dungar]

If there is an area where the foam is allowed to be exposed (I have never seen one), then the NM cable is in no danger because it would never have any people anywhere near it.

I have yet, in the past 15 years, to be in a basement that does not have uncovered closed cell insulation sprayed on the rim boards (between the foundation and the flooring) and any NM cables that happen to be there.
This is a quote, probably a little dated, from an insulating contractor "the IRC allows spray foam at the rim joist area to be left exposed, without any protective drywall. The relevant provisions can be found in section R316.5.11 (this can be found in all versions of the IRC, from 2009 through 2018)."

 

[garbo]

When I started wiring houses in '82, the conductors in the NM cable were covered with TW insulation. That's 60 C or 140 F. This is in Orlando, FL where in the summer, I can pretty much bet that the temperature in the attic can exceed 140 F. This means that my 14-2 home runs in the attic can not have even .5 amp of current flowing through them without exceeding their temperature limitations. And here I thought I always did quality wiring jobs!

Often wondered why it took foot dragging NEC at least15 years to make NM cable manufacturer's to switch over to the far superior what appears to be THHN insulation. My electrician dad bought home a sample of THHN or THWN ( not sure if it was dual rated back then ) around 1967. My Vo Tech shop teacher never saw it and when my dad placed an order for a dozen rools to test it owner of the industrial electric supply house did not know what he was talking about. Supply house owner called wire company and ripped them a new one. Supply house apologized and somebody paid to have a few roo!s fast shipped. First year that THWN appeared some contractors were using #14 gauge THWN on 20 amp circuit breaker because it was rated for believe 105 degrees C in dry area's. While I'm on a rant how did testing labs pass so many different brands of 50 amp flimsy 240 volt receptacle that appears a large # burn up within a year while feeding EV chargers. Steve wonder would have performed a better testing procedure.

 

[letgomywago]

Often wondered why it took foot dragging NEC at least15 years to make NM cable manufacturer's to switch over to the far superior what appears to be THHN insulation. My electrician dad bought home a sample of THHN or THWN ( not sure if it was dual rated back then ) around 1967. My Vo Tech shop teacher never saw it and when my dad placed an order for a dozen rools to test it owner of the industrial electric supply house did not know what he was talking about. Supply house owner called wire company and ripped them a new one. Supply house apologized and somebody paid to have a few roo!s fast shipped. First year that THWN appeared some contractors were using #14 gauge THWN on 20 amp circuit breaker because it was rated for believe 105 degrees C in dry area's. While I'm on a rant how did testing labs pass so many different brands of 50 amp flimsy 240 volt receptacle that appears a large # burn up within a year while feeding EV chargers. Steve wonder would have performed a better testing procedure.

I like Stevie wonder tennis fake ad he did for SNL even he sees the humor in this kind of joke

 

[NEC Inspector]

I have yet, in the past 15 years, to be in a basement that does not have uncovered closed cell insulation sprayed on the rim boards (between the foundation and the flooring) and any NM cables that happen to be there.
This is a quote, probably a little dated, from an insulating contractor "the IRC allows spray foam at the rim joist area to be left exposed, without any protective drywall. The relevant provisions can be found in section R316.5.11 (this can be found in all versions of the IRC, from 2009 through 2018)."

Good point. Still correct in the 2024 edition, they just moved the section number to 303.5.11

CHAPTER 3 BUILDING PLANNING - 2024 INTERNATIONAL RESIDENTIAL CODE (IRC)

ICC Digital Codes is the largest provider of model codes, custom codes and standards used worldwide to construct safe, sustainable, affordable and resilient structures.

codes.iccsafe.org

As long as they can meet the flame spread index of 25 or less. For some reason, most people I have confronted would rather cover the foam then give me the specs on what they used to make sure it complies. I have always pretty much assumed that what is used locally doesn't comply for that reason, but it certainly could.