Electrical tape comes in four different varieties, including rubber, vinyl, mastic, and varnished cambric.
Rubber
Rubber electrical tape is usually nonadhesive, which means that to properly use it you will need to stretch the tape and tightly wrap it so that it can physically adhere to itself using the elastic tension of the backing. This type of tape typically is used for splicing and terminating wires or cables rated up to 69 kilovolts (KV). Rubber electrical tape also can add water resistance and insulation to electrical connections.
Vinyl
Vinyl electrical tape is the most common type of electrical tape for use in the home. It has an abrasion-resistant PVC backing that is long lasting and flexible, making it ideal for insulating the wires and electrical connections during electrical tapping. This type of tape also protects against moisture, though its primary purpose should be as an economical wire and electrical connection insulator. Vinyl electrical tape can also be used for repairing minor nicks and cuts in your wires, making it an ideal addition to your wire stripper, cable ripper, and other electrical tools.
Mastic
Mastic is the portion of the tape that makes up the spongy center between the backing and the adhesive. You can find mastic electrical tape with a vinyl backing, a rubber backing, or without a backing, giving you plenty of options if you need versatility on your projects. Mastic electrical tape is used regularly by professional electricians because it adheres easily and can be manipulated to fit in tight spaces or around oddly shaped components. This type of electrical tape is able to insulate metals, rubbers, and synthetic cable jackets, while providing a complete moisture seal and even UV resistance, making it ideal for outdoor electrical connection sealing and repairs.
Varnished Cambric
Varnished cambric electrical tape is made of straight-cut woven cotton fabric primed with oil and coated with an electrical insulating varnish. This is to ensure that it can insulate electrical currents without being damaged by the energy that passes through the wire. This type of electrical tape is ideal for covering bolts, corners, and other rough edges that might cut through a less durable electrical tape. Use it for insulating areas in your home or on your vehicle where mechanical protection and puncture resistance is necessary.