Reel of megohmoid insulation tape . Soiled white paper packaging containing reel of insulation tape.

Part of the Bob Gray collection of electrical objects.

Electrical insulation tape has been used since the early days of electricity for convenient, on-site repairs, patches, and improvements, to keep out moisture and provide insulation. Although using insulation tape is not done in the best class of wiring work it is an essential part of any electrician's tool kit. From the 1930s to the 1950s rubber strip was used but it was superseded by PVC in the late 1950s. This strip was made by Megohmoid. The name suggests that the tape was highly resistant to electricity given that electrical resistance is measured in ohms.