Spray Foam & Romex

[Alwayslearningelec]

So hoping I can get a little help/advice here.

Had my attic ceiling spray foam insulation done. All along the perimeter it becomes pretty tights. I had a bunch romex run along the rafters which they completely covered with the spray foam. I mean like 4+ inches of spray foam encapsulating the romex cables.

Is this dangerous and could this cause overheating. They said they do this all the time. Thanks.

 

[petersonra]

How is this much different than putting fiberglass insulation over top of Romex?

 

[Alwayslearningelec]

How is this much different than putting fiberglass insulation over top of Romex?

Ok, good point.

 

[electrofelon]

How is this much different than putting fiberglass insulation over top of Romex?

Ok, good point.

The counter argument is that spray foam is a much better insulator and prevents all convection, unlike fiberglass.

 

[infinity]

For individual runs of cable there is no issue.

 

[Dennis Alwon]

I have seen it many times and with nm rated at 60C I don't think it is an issue.

 

[electrofelon]

I seem to remember some testing on this, but I can't remember where or what the result was.

 

[ActionDave]

I seem to remember some testing on this, but I can't remember where or what the result was.

Somebody took some romexs, stuffed them a hole in some wood and added spray foam and then ran max current through it. That's how we ended up with that stupid rule about romex in holes with spray foam.

 

[ActionDave]

So hoping I can get a little help/advice here.

Had my attic ceiling spray foam insulation done. All along the perimeter it becomes pretty tights. I had a bunch romex run along the rafters which they completely covered with the spray foam. I mean like 4+ inches of spray foam encapsulating the romex cables.

Is this dangerous and could this cause overheating. They said they do this all the time. Thanks.

I wouldn't worry about it a bit.

 

[sparky1118]

It's done around here all the time with new homes. Personally I hate that stuff. But it is required to meet the energy rating.

Sent from my SM-G998U using Tapatalk

 

[Hv&Lv]

I had mine insulated like that a few years ago also.
Same scenario.
Didn’t consider it a problem because the interior of the attic was about 140f. The spray foam encapsulating the romex is keeping it cooler now

 

[Knuckle Dragger]

I wouldn't worry about it.
Note: Closed cell spray foam can get warm to hot while curing. It's been known to be the cause of some house fires if not applied properly.

 

[ptonsparky]

I have it on all the poured basement walls. NM sprayed tight. Ten years or so and still good. I’ll let you all know if there is a problem, providing I survive the smoke.

 

[Fred B]

I think any concern over foam use and NM related to heating on the conductors may have some merit dont know for sure, but fiberglass batting or even blown in has air movement throughout the wiring space and even around the boxes. That air movement is why the change to foaming for energy code compliance, but I also think it is another cause of "sick home" syndrome that is becoming more common from lack of fresh air.

Rant alert!
Good luck having to change anything after spray foaming has been done. I've even seen substantial infiltration of foam into the blue boxes used for NM.
Try to explain to HO when they ask for another outlet be put in and how long it'll now take after foaming done and that foam will need to be dug out to make that change.
I swear some of these guys go out of their way to get coverage onto the wire that are set up for lighting drops that isn't even close to the roofline that they are spraying. I've even found protector plates laying on the floor after the foam guy shaves the excess foam from the wall (now where was that wire that needed the plate?).
Really bad on older home renovation that is only 2x4 construction, been told the only way they meet the energy code requirements is with cavity completely filled with foam.
Any ideas that makes it easier to make changes or additions after foaming done? Or do we need to start wiring after the foam guys are done? Or start piping everything on insulated walls or ceilings?

 

[goldstar]

I understand there is probably little or no impact on the cable(s) regarding insulation value. However, you'll always get that ONE EI that will tell you that there may be a "chemical reaction" of the foam when in contact with the cable and whether you have any documentation stating that it doesn't have that reaction. I sometimes get the same question when I use a silicone sealer where SE cable enters the top of a meter pan instead of using duct seal. I simply ask them to cite a Code section.

 

[LarryFine]

Any ideas that makes it easier to make changes or additions after foaming done? Or do we need to start wiring after the foam guys are done? Or start piping everything on insulated walls or ceilings?

Conduit is the only real future-proofing.

 

[electrofelon]

Here on the northeast, spray foam has been pretty much the standard for quite a while now. I have not had any problems and would not insulate a house any other way.