3M 70

Harmonization Code : 3919.10.80 | Other self-adhesive plastic rolls not exceeding 20 cm wide.

3M 70

Main features

  • Instant Self-Fusing Cable Overwrap
  • Class H High-Temperature Insulation
  • Arc-Resistant High-Voltage Protection

Product Description

Scotch Self-Fusing Silicone Rubber Electrical Tape 70 is a high-temperature, self-fusing inorganic silicone rubber tape for electrical insulation and protective overwrapping. It fuses to itself without a pressure-sensitive adhesive and uses an easy-tear, easy-strip liner for hand application. The tape provides high dielectric strength with arc and track resistance and is a Class H material for continuous operation at 180 deg C. Applied in half-lapped layers with moderate tension, it forms a fused protective wrap for high-voltage cable and other high-temperature electrical insulation work.

Key features

  • Instant self-fusion: The silicone rubber fuses to itself without a pressure-sensitive adhesive and does not need to be held down after wrapping.
  • Class H temperature capability: The 180 deg C continuous Class H rating applies to high-temperature primary insulation applications.
  • Arc and track resistance: High dielectric strength with arc and track resistance suits protective overwraps on high-voltage terminations.

Applications

Applications include high-voltage cable termination overwraps, Class H primary insulation, spacer-cable splice overwraps, and outdoor electrical protection.

Product Family

3M 70

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Color
The color
Munsell 5BG7.0/0.4 Sky Blue Grey
Total Thickness
Total thickness is taking into account all the films, coatings, adhesives, release liners and special layers and is the maximum thickness of a film or tape.
300 μm
Mechanical Properties
Elongation
Elongation is the process of lengthening something. It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks. It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.
450 %
Electrical Properties
Arc Resistance
ASTM-D495 expresses arc resistance as the number of seconds that a material resists forming a surface-conducting path when exposed to a high-voltage, low-current arc occurring intermittently. Results obtained from a nominal 3 mm thickness are meant to represent the material’s reaction in any thickness.
60 s
Dielectric Strength
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow.
34 kV/mm

Additional Information

Technical properties

As-supplied / before-processing properties

PropertyValueUnitMethod / condition
ColorSky Blue GrayMunsell 5BG7.0/0.4
Thickness0.012inTypical; ASTM D1000-10
Tensile strength12lb/inTypical; ASTM D1000-10
Elongation at break450%Typical; ASTM D1000-10
Technical properties

After-processing / final-state properties

PropertyValueUnitMethod / condition
Dielectric strength875V/milTypical; ASTM D1000-10
Arc resistance>= 1minTypical; ASTM D495-71
Continuous operating temperature180deg CClass H material

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