service panel question

[ROBERT YOUNG]

Is there a clearance for service panels from spray foam insulation?
The service panel is encapsulated on 4 exposed sides with spray foam insulation.33065

[Jerry Peck]

The real question is about the NM cables being embedded in the thermal insulation.

I am not sure about the panel being embedded in the insulation, but I don't see a problem with it installed in the insulation (albeit I am not sure how the testing is done - in free air or in insulation, but panels do get installed in walls which are insulated, so I would lean toward that not being the issue.

The known issue is the NM cables embedded in the thermal insulation and derating - see 334.80

[Raymond Wand]

Robert

As it relates to a Canadian Electrical Code issue since you are in Canada.

http://gfretwell.com/electrical/nema_romex_in_foam_study.pdf

I can also tell you that spray foam in a new house I just constructed was fully foamed and the ESA inspector approved everything.

Can's speak to foaming entirely around the panel, for my own liking I don't think that was a good idea.

Addendum
https://sameo416.wordpress.com/2013/01/18/derating-of-electrical-cables-in-thermal-insulation/

Best

[Grant Medich]

I noticed the embedded NM cables right away as well. As for the actual panel, I think we are looking at one of those situations where things don't look quite right, but there is little to support a significant concern.

I had spent a few years in commercial construction before migrating into residential projects. I am sometimes puzzled that certain product solutions are seldom used in residential construction.

Three which come to mind are mineral wool, fire-rated expanding foam insulation, and heat-expanding caulk. I have seen each of these used frequently in fire-break assemblies for both walls and floors. They are easy enough to find in any locality in which I have worked, and do not require more than basic knowledge of how they work to properly apply them.

Although they would not mitigate our concerns about the embedded NM cables, they would allow the panel to be insulated without other concerns.

[John Kogel]

This does raise the question - If exterior walls can be filled with spray foam, how can there be any objection to embedding the wiring in foam?

Wiring in an attic should be buried in the insulation as much as possible, as it is cooler in the summer months under the insulation than it will be in open air.

[Jerry Peck]

This does raise the question - If exterior walls can be filled with spray foam, how can there be any objection to embedding the wiring in foam?

Wiring in an attic should be buried in the insulation as much as possible, as it is cooler in the summer months under the insulation than it will be in open air.

The difference is that the wiring coming out of the panel is typically not paid the proper attention for maintaining spacing/not bundling, which in and of itself is a problem. Put that same workmanship lack of care in thermal insulation and the problem gets worse.


It is a common problem (and one which many pooh-paw, but which is in the code and in there for a reason) and that lack of maintaining spacing leads to derating issues.

Lack of maintaining spacing not in thermal insulation is based on 24 inches or greater length.

Lack of maintaining spacing in thermal insulation is based on the wiring being in thermal insulation.

It does not say 'spray foam,' it says 'thermal insulation', ANY insulation which has thermal values, i.e., fiberglass too.

[ROBERT YOUNG]

Much thanks for the reply everyone.
I thought, 1: fire and 2: maintenance would prohibit this practice.

I could not find anything in the NEC and was certainly perplexed.
Now, I am not stateside but, the issues of fire safety usually cross jurisdictions or one would hope.
When it came to CSA, they were approached by an individual that wrote an article with two colleagues on the subject. UK has taken a different approach.
Derating ampacity. Link removed.

Thanks again. Much appreciated.

[Jerry Peck]

"As I mused, the fire burned" https://sameo416.wordpress.com/

Leave the religious bunk out.

Much appreciated, thanks.

[Raymond Wand]

Robert

Further info.

Contrary view and study.

http://goodsonengineering.com/wp-content/uploads/Effects-of-Polyurethane-Foam-Systems-on-Wiring-Ampacity.pdf

.. and ..

Ontario Electrical Safety Code - Bulletins
May 2012
http://www.hvactechgroup.com/files/Bulletin%2012-19-11.pdf


The use of spray foam polyurethane insulation in walls that have NMSC already installed in a manner that is in compliance with the OESC is also acceptable. (OESC - Ontario Electrical Safety Code)

[ROBERT YOUNG]

Leave the religious bunk out.

Much appreciated, thanks.
Ops.Wrong Link.

[ROBERT YOUNG]

Robert

As it relates to a Canadian Electrical Code issue since you are in Canada.

http://gfretwell.com/electrical/nema_romex_in_foam_study.pdf

I can also tell you that spray foam in a new house I just constructed was fully foamed and the ESA inspector approved everything.

Can's speak to foaming entirely around the panel, for my own liking I don't think that was a good idea.

Addendum
https://sameo416.wordpress.com/2013/01/18/derating-of-electrical-cables-in-thermal-insulation/

Best
Stateside or Canada, the practice requires further review.
I prefer to see as wide a codified a spectrum as possible. What is implied in reports is typically NBCC.
here is more on the subject.
http://goodsonengineering.com/wp-content/uploads/Effects-of-Polyurethane-Foam-Systems-on-Wiring-Ampacity.pdf