Raychem makes several heat shrink tubing families, and they are not interchangeable. Two are for cables (WCSM and MWTM) and two are for busbars (BBIT and BPTM). Start with what you are covering, then match the wall and size.
| Job | Pick | Why |
|---|---|---|
| Cable jacket repair or sealing, heavy duty | WCSM | Heavy wall, 4:1 shrink ratio, adhesive lined |
| Cable jacket repair or sealing, lighter duty | MWTM | Medium wall, 3:1 shrink ratio, coated or uncoated |
| Rejacketing JCN cable | MWTM | TE lists it as RUS accepted for JCN jacket restoration |
| Busbar insulation up to 36 kV | BBIT | Heavy wall, UL approved, flashover protection to 36 kV |
| Busbar insulation up to 25 kV | BPTM | Medium wall |
| Wildlife protection on bus | BBIT or BPTM | Insulates the bar against animal contact |
WCSM is the heavy wall option. TE lists a recovered wall of 2.0 to 4.5 mm depending on size, a 4:1 shrink ratio and an adhesive lining for moisture sealing. Coated WCSM is rated for -40 to +100 degrees C operating, installs above 120 degrees C, and is halogen-free. Use it where the covering needs to take abuse.
MWTM is the medium wall option with a 3:1 shrink ratio. It comes coated for sealing or uncoated (-U or -A/U). Uncoated MWTM is for rejacketing only, not sealing.
If both would fit, the deciding factors are wall thickness and diameter range. A higher shrink ratio means one size covers a wider range of cable and connector diameters. Full size tables are in our WCSM vs MWTM guide.
Both shrink over copper or aluminum bar, straight or bent, and both help reduce clearances in switchgear. BBIT is the heavy wall tubing with flashover protection to 36 kV. BPTM is the medium wall tubing for lower voltage classes. Sizing is by width plus thickness for rectangular bar, or by diameter for round bar. Details and size tables are in our BBIT vs BPTM guide.
Heat shrink needs a propane torch, hose and regulator. See our Raychem torches and accessories guide.
No. Use BBIT or BPTM, which are made for bus insulation.
No. Cable work uses WCSM or MWTM.
Coated tubing seals against moisture. Uncoated MWTM is for rejacketing only.
No. Tubing repairs, seals or insulates. Splicing and terminating use kits like the CSJA or CST.
Powertech Associates and Utility Power Supply Company represent TE Connectivity across New England and New York State. Send us your cable or bar dimensions and we will match the size. Contact Powertech Associates at info@powertech-upsc.com or (860) 678-8772.
Last updated: October 2026.
