What to use to seal an exterior cable penetration in brick?
Duct seal. The stuff from the electrical aisle, not the stuff with a similar or identical name from the HVAC aisle.
A non-hardening putty for sealing electrical ducts (conduits, holes in the wall) against water and insects.
Usually gray. Removable and reusable. Comes as a &quot;bar&quot; or &quot;brick&quot; of putty in a plastic bag (at least when I've gotten it.)