3M STFF | Fire Resistant & Halogen Free Cable Joints

Published 29 Apr 2019

3M STFF Joint Protection Sleeve

  • uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager


Smoke, Toxicity, Flame, & Fume Protection For Cable Joints

3M STFF Shield products are designed for use with all inline polymeric cold shrink and resin cable joints – this includes LV, 600/1000 volts, 3.3kV, 6.6kV, 11kV and 33kV cable joints and cable abandonment kits. 3M STFF Shield is suitable for single and three core polymeric cold shrink joints, as well as for cable abandonment applications at low voltage.

The addition of the 3M STFF Shield will allow standard cable joints and accessories to be installed in areas such as underground rail, tunnels and any application where flame retardant, low toxicity cable jointing solutions are required with fire resistance.

3M STFF Shield products have been approved for London Underground LU Standard 1-085 and the universal joint protection system complies with Section 12 of the London Underground Network – the product range is commonly known as the Smoke, Toxicity, Fire and Fume joint sleeve or STFF.

  • S – SmokeLondon Underground Cable Joints
  • T – Toxicity
  • F – Fire
  • F – Fume

The 3M STFF joint protection sleeve include standard sleeve for cable joints, a closed-end sleeve for cable abandonment applications as well as a retrofit wrap to wrap around cable joints that have already been installed.

Cable Joints

Fire Resistant Shield for Joints & Cables In Rail Tunnels

3M STFF Shield Products

3M STFF Shield Product Features & Benefits

  • 3M STFF Shield products are made up of layers of woven glass fabric, and high temperature silica to enable flame resistance, and prevention of smoke, and toxic fumes
  • Halogen Free
  • Manufactured in several sizes enabling compatibility with a wide range of 3M Cable accessories
  • Easily secured in place with integrated fastening straps, no need for cable ties or tools
  • 3M STFF are available as a sleeve design for covering cable joints, or a closed end covering for cable abandonment applications
  • Available as a wrap around design for retrospective fitting around cables already installed

Used with Cold Shrink Joints Manufactured by 3M Electrical

3M STFF used in conjunction with Cold Shrink joints provide halogen free and fire resistant joints suitable for installation onto cable containment – the STFF joint is compact and smooth profile with reduced space displacement and weight impact.

This type of cable joint is not suitable for direct burial (underground) as the STFF protective shield will absorb moisture.

  • LCI Joint Kit 16.2mm-33.1mm – Order Code 3M LC1-STFF13
  • LC2 Joint Kit 16.2mm-33.1mm – Order Code 3M LC2-STFF13
  • LC3 Joint Kit 16.2mm-33.1mm – Order Code 3M LC3-STFF13
  • LC4 Joint Kit 24.9mm-56.4mm – Order Code 3M LC4-STFF14
  • LC5 Joint Kit 37.8mm-84.3mm – Order Code 3M LC5-STFF14
  • LC6 Joint Kit 37.8mm-84.3mm – Order Code 3M LC6-STFF14
Cold Shrink Joints

Cold Shrink LC Joints by 3M Electrical

Network Rail & London Underground Approvals

  • Compliant with London Underground Engineering Standard 1-085. Product Approval List No: 1106
  • Network PADS Approved Product: PA05/04396
  • Smoke Emissions and Toxic Fume Emission testing has been carried out to BS EN50268-2:2000 and BS 6853:1999 Annex B.2 respectively.
3M STFF Cable Joint Shield

3M STFF Cable Joint Shield


The STFF Shields are supplied only as part of the cable joint / accessory kit from 3M. The sleeve is slipped onto one of the cables ready to be joined and parked back along the cable.

The cable joint is made off in the normal way and the STFF sleeve is now slid over the joint and held in place by two stainless steel cable ties, one at each end.

Full installation instructions are supplied with each 3M Electrical kit.

LV Cable Joints (Low Voltage Cables)

Thorne & Derrick stock and distribute LV Joints in Cold Shrink, Heat Shrink or Resin Cast technologies – multicore and multi-pair cable joints are available for immediate backfill and energisation of Low Voltage power, control and instrumentation cables 600V/1000V 3.3kV.

Complete range of LV Cable Accessories  ➡

Cable Breakouts | Cable Caps | Cable Lugs | Cable Cleats | Cable Trough | Cable Duct | Feeder Pillars | for 11kV/33kV/66kV networks see MV HV Joints & Terminations

Joints Terminations Connectors

Pfisterer | Nexans Euromold | Prysmian | Cable Joints & Terminations MV HV

Cold Shrink

Cold Shrink by 3M | Joints | Abandonment | Terminations | Low Voltage LV Cables

Further Reading

  • T&D Size: