Scotch® Fire-Retardant Electric Arc Proofing Tape 77W is a 30-mil thick, premium grade, flame-retardant, electric arc proofing tape used to help protect most types of electrical cables from fault arc-generated heat and flames of nearby cable failures. These halogen-containing elastomeric tapes are formulated to generate a thick, insulating charred buildup when exposed to high temperatures. The insulating charred buildup protects wrapped cables and cable accessories from the fault arc-generated heat and flames of cable failures within approximately 20 inches until limiting devices can interrupt the faulted circuit. The tape's thin cross section reduces the overall weight compared to other methods while providing arc protection. The white gray color of Scotch® Tape 77 White allows for easy identification of burned areas. One half-lap wrap provides adequate protection for most installations. However, additional wraps can be applied, if conditions warrant, without requiring a reduction in conductor loads. Wrap Scotch® Tape 77 in half-lapped layers. The tape should be stretched slightly to obtain a snug, wrinkle-free wrap which conforms to the cable. Overlap the last 6 inches of protected cable when starting a new roll of tape. Since the Scotch® Tape 77 Series is not adhesive coated, it must be held in place after wrapping with bands of Scotch® Glass Cloth Electrical Tape 69. One of the most effective and economical ways to hold either of these tapes in place is by banding (2 complete wraps) the first and last applied wrap.