Spray Foam Insulation in Electrical Panel

I was hoping there was a way to just give them access to the members-only section of the forum, not necessarily give them free NACHI membership. But on that note, I would also say NACHI membership should also be free to the old timers who have paid dues after a certain number of years. Especially those that are retired and still come here to help others.

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So, talking with my master electrician contact. He stated that it would be considered a foreign material inside the panel box, as spray foam insulation is a flammable material, and one of the main purposes of the electrical panel box is to contain any unexpected heat/sparks inside the electrical panel box. Now there is a flammable material inside the electrical panel box.

Now, he also stated that the bigger problem with this one, is the height from the floor to the electrical panel box, as it looks to be installed too low. The minimum height from the floor to an electrical panel box is 4 feet.



There is no minimum height in the NEC so if he’s citing code it must be a local amendment. I would be more concerned about the big black flexible cord (bottom left) that is in the panel and is therefore buried in the wall covered in spray foam.


According to Great Stuff cured foam is flammable above 240 degrees F. Not within the normal operating temperatures of a panel.

As much as this “technically” may be a deficiency, I’d rather see a little bit of spray foam in a place that will never be an issue, than see the open conduit allowing condensation into the panel.


Condensation from where? It appears to be an interior panel within the building envelope.


From the cold service conduit that leads to the outdoor meter.

Penetrations thru the building envelope are typically handled at the entry point.

You and I have drastically different climates. Is condensation inside a panel a thing up there?

I see problems with outdoor panels, panels in carports or areas of high humidity such as laundry rooms or poor performing basements.

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We have a lot of mixed weather conditions here. I haven’t seen very many panels with condensation problems, other than in areas, such as you’ve mentioned. I have never seen it, where they have had to contaminate a panel with spray foam insulation, to prevent condensation from getting into the panel.


Ryan is correct. Raceways that go from one environment to another (like outside to inside) are required by the NEC to be sealed on one end. For years we always used duct seal but now with the prevalence of spray foam that is being used as well to seal raceways. The NEC only requires that the sealant be suitable for contact with the conductors.


It can be, albeit the OP’s panel would be an unlikely candidate for it on further review, as I’m thinking there is no conduit to the outdoors for the SEC in his case., and the SEC enters from below which would also lessen the chances.

Most panels in my area are in conditioned basements. Warm moist air from the basement travels into the panel and into the cold conduit which is more or less “open” to the outdoors. Condensation forms in the conduit and runs back into the panel.


There are some specific sealants designed for this use that are more suitable than spray foam, but as Robert pointed out above, spray foam is common.

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Inside the panel box? To include the branch circuits? I need to get out more :wink:

On the SEC yes, but not on the branch circuits, lol. And the SEC conduit being not sealed is most common, but when it is, spray foam is a common sealant. I’ve also seen caulk and other putty-like substances as well as fiberglass insulation at times.

Okay, I follow you. When the entrance conduit penetrates the building envelope and is connected directly to the interior panelboard…the conduit should be sealed at some point in between. And spray foam in the panel board is an acceptable means?

Foam insulation=Flammable. NEC didn’t say to use it in there, so…improper hardware.

Well, I don’t know that it is specifically prohibited I guess. I suppose the fire retardant stuff would be best.

There is no fully fire retardant spray foam insulation. Some of it is treated with fire retardant to help lower the chance of it burning. As for what Robert said, he may do it like that in his neck of the woods, but that’s not to say it’s right, or that it’s an acceptable method. I didn’t find anywhere online to state that it is okay to put spray foam insulation inside the electrical panel.
My master electrician contact stated that electricians around here would flip if they seen that, along with the height of the panel from the floor.
That being said, I would call it out for the foreign material, same as any other contamination. The panel does look to be installed low. If so, that would be something as well, as it would be in easy reach of children. Recommend to a qualified electrical contractor for repair, and be done with it. Not saying anyone will ever do anything about it, but…


Yup… the result being this ‘new’ POC forum system we now have to deal with!!


Still miss the old forum. :slight_smile: