Hi
What product can be used to close holes in electrical panels, wall cable entry? We have been requested not to use Sika Boom as in case of fire, toxic fumes are produced.
Is this a fire wall? If so, not all Sika Boom® products are acceptable as fire stop caulk.
The generic search term is "Firestop sealants, caulks, and putties". Just to show the range of products available, Grainger's catalog lists 92 products.
Stuffing openings with mineral wool can also be accepted.
The product you choose, needs to meet the listing requirements of the Authority Having Jurisdiction in your location.
There is not enough information in your post to suggest anything further. Providing some more information will get better answers.