Securing NM-B in ICF walls

[rszimm]

I've never done an ICF structure before. I've got the cables all run in channels carved out of the foam (2-1/2" thick foam), but now I need to secure them 12" from the boxes and 4.5' along the horizontal runs. From what I've seen online, people tend to just put dabs of spray foam over them either along the whole run, or at the 12"/4.5' intervals. That seems to be pretty secure, but my reading of 334.30 doesn't seem to allow this. This is odd to me because a blob of spray foam seems to hold the cables far more securely than something like those plastic trees that are specifically listed to hold nm-b cables.

 

[infinity]

It's really up to the inspector to decide what is acceptable. I agree with you there are spray foams or adhesives that will hold the cable in place just fine.

 

[Dennis Alwon]

I believe we used staples but they don't hold well if you pull on it. You could always use those one hole straps.

 

[rszimm]

Staples into the concrete? The one hole straps tapconned into the concrete are probably my backup plan, but that's a lot more work than just blasting a blob of foam every 4', and I really don't think it's any more secure.

 

[rszimm]

Incidentally, I notice that the plumber ran his pex lines the same way I did and then just covered the whole run with foam, so that's probably a good indication as to what this particular inspector is likely to accept. Just wish the code had some specific guidance here...

 

[infinity]

There's probably a dozen different ways to do this. You could Ramset a strip of wood to the concrete and staple the NM cable to the wood.

 

[Dennis Alwon]

Staples into the concrete? The one hole straps tapconned into the concrete are probably my backup plan, but that's a lot more work than just blasting a blob of foam every 4', and I really don't think it's any more secure.

If it the stuff we used there was a bit of that foam there for the staple to catch