Scotch Tape 77 is a 30 mil thick, premium grade, flame retardant, electric arc proofing tape. This tape is 600V rated and is suitable to protect most types of electrical cables when exposed to potential failures in an adjacent cable. It is designed with a flexible unsupported elastomer, which makes it easy to apply and easy to remove for cable inspection.Scotch Fire-Retardant Electric Arc Proofing Tape 77 is designed to protect most types of electrical cables when exposed to potential failures in an adjacent cable. Its specially formulated adhesive expands in fire to form a thick char build-up between the flame and the cable.