Fiberglass insulation in electric panel

I have searched the world-wide web and haven’t found anything prohibiting this but do any of the electrical gurus see this as a reportable deficiency (fiberglass insulation inside of the electrical panel).

Not a guru but most likely someone want to stop cold draft or keep pest from entering.

Fiberglass insulation is not flammable . However, the glue that holds it together off-gasses formaldehyde constantly, and can release toxic fumes if there is a fire or enough heat.

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Draft stop is required for a raceway that is subject to different temperature air like inside and outside. We use duct seal. Here’s the NEC code reference:

300.7 Raceways Exposed to Different Temperatures.
(A) Sealing. Where portions of a raceway or sleeve are known to be subjected to different temperatures, and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be filled with an approved material to prevent the circulation of warm air to a colder section of the raceway or sleeve. An explosionproof seal shall not be required for this purpose.

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Thank you Robert. So then the obvious question, is fiberglass insulation an approved material? I found lots of info on the web referencing the preference for duct seal but have not found anything prohibiting fiberglass insulation.

Wouldn`t the fiberglass still allow for moisture vapor to pass through and also to absorb moisture creating an issue?? Thanks

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I can’t comment if it’s approved, but I doubt it.

First, fiberglass is not an air barrier at all.
Second, it burns remarkably well, not exactly sustaining a fire, but hardly acting fireproof either:

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The fiberglass is not an approved material. The code section in my first post was from the 2017 NEC. The 2020 NEC has expanded the requirement to include wording that states that the material must be identified for use with the conductor insulation.

2020 NEC:
300.7 Raceways Exposed to Different Temperatures.
300.7(A) Sealing.
Where portions of a raceway or sleeve are known to be subjected to different temperatures, and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be sealed to prevent the circulation of warm air to a colder section of the raceway or sleeve. Sealants shall be identified for use with cable insulation, conductor insulation, a bare conductor, a shield, or other components. An explosionproof seal shall not be required for this purpose.

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