Electrical tape, like silicone caulk, isn't something that you should trust with keeping your home or belongings safe from flames and toxic gases because it will only dry out over time leaving behind residue that can be extremely dangerous when exposed to heat. If you are looking for an option other than firestop sealant then we recommend using fire resistant board (FRB) which has similar properties without containing asbestos fibers like cement products do. It's important to remember that even FRB needs some sort of additional support in order for it work properly so if this just won’t work for your particular application then we recommend using firestop sealant.