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Black EPDM rubber cold-shrink tube, 12 in long, 1.38 in diameter before shrinking

3M

3M 8427-12 Cold Shrink Tube Medium Wall 1.38 in

SKU CH-JCPC-9C732

EPDM rubber cold-shrink tube covers 250–400 MCM wire, shrinking from 1.38 in to .69 in ID over a 12 in length

  • Cold-shrink installation needs no heat tools
  • EPDM rubber resists UV and outdoor weathering
  • Fits wire sizes from 250 MCM to 400 MCM
  • Shrinks from 1.38 in to .69 in ID
  • Operates from -40 to 194 degrees F

Product Purpose

The 3M 8427-12 Cold Shrink Tube is a medium-wall EPDM rubber insulator designed for electrical wire splicing and termination. It fits wire sizes from 250 MCM to 400 MCM and installs without heat tools, making it suitable for field electricians and maintenance crews who need a fast, reliable seal.

Shrink Ratio Limitation

This tube carries no rated shrink ratio, so the final grip depends on the cable diameter falling within the 1.38 in to .69 in range. It cannot compensate for undersized conductors or expand beyond the supplied dimensions, and it lacks an adhesive lining for environmental sealing.

Critical Sizing Spec

The decisive figure is the inner diameter after shrinking: .69 in. If the finished cable assembly exceeds this diameter the tube will not seat; if it is significantly smaller the wall may not compress enough to hold. Verify the final outer diameter before ordering.

How it compares

Measured against everything we stock in Electrical Trade Tools & Kits, at today’s prices. Recalculated every night.

Price $45.99
Cheaper than about 80% of the 5,006 comparable items (median $95.99).

Specifications

Product
Brand name3M

Questions about this item

Which cold-shrink tube size fits 250 MCM to 400 MCM wire?

The 3M 8427-12 is specified for 250 MCM to 400 MCM conductors with a 1.38 in pre-shrink diameter that shrinks to .69 in.

What does the 1.38 in pre-shrink diameter mean when installed?

It slides over the cable easily, then shrinks down to .69 in to form a tight seal over 250 MCM to 400 MCM wire.

Is the tube rated for a specific shrink ratio or industry standard?

The shrink ratio is not rated; the tube relies on its EPDM rubber memory to shrink from 1.38 in to .69 in without a defined ratio.

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