Mastic Electrical Tapes – Guide and How to select

The term “mastic” is widely used in the construction industry, especially by tile setters. Many electricians don’t realize that the gooey electrical tape they use to resist moisture is also a mastic. But this mastic rubber material is specially formulated for use as a dielectric insulator.

When you are working with odd shaped components or needing to tuck in some insulation where your tape won’t reach; mastic is the product to use. Think of it as putty on a roll.

In addition to low-voltage electrical insulation, mastic tape offers the best moisture resistance of any electrical tape made by 3M. They create a barricade around splices and terminations, so that they are resistant to contaminants and particles that can corrode your wire and connections. Mastic tapes are often used in outdoor applications because the rubber is ‘self-healing’, meaning that when it is punctured, the material will flow to fill in the void.

We recommend it for use within industrial environments where steam and aerosols are commonly present, and outdoor environments where connections need to resist humidity and moisture.

Mastic tapes provide mega-stretch−up to 1000 times their original length. Sharp edges and bolted connections create potential puncture risks and failure modes for your splices which can result in costly downtime and repairs. With multiple configurations and thicknesses of moldable and stretchable sheets, rolls, putty and laminated combinations, you can shape, smooth and pad just about any electrical connection.

There is another mastic application electricians may be surprised to learn about. Mastic tape can be used to deter pests. Fire ants in the Southeastern U.S. create headaches for electricians by attacking pad mounted transformers, traffic control panels and ground level air conditioning units. *According to research done at Texas A&M University, the insects are attracted to the electrical fields, especially around relay switches. Power surges caused by these pests can cost thousands of dollars in electronics repairs or even human lives if those relays operate train switches.

Pests and rodents can cause havoc. Help reduce your regular maintenance costs with a simple mastic solution.

^{*Merchant, Mike. “Insects in the City: Fire ants shock homeowners.”
http://insectsinthecity.blogspot.com/2009/06/fire-ants-shock-homeowners.html (accessed September 15, 2017).}