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FIGURE 4: Oil barrier tube used in a 3-core paper cable joint.
(TE Connectivity)
FIGURE 5: Flame-retardant heat-shrink cable accessories in a
vertical tray arrangement. (TE Connectivity)
This function usually needs to be maintained for a
service life of 40 years under maximum operating
temperatures of the cable conductor in the range
of 70°C. Heat-shrink materials with oil-blocking
characteristics can also be used in the oil and gas
or petrochemical industry applications, where oil-
blocking features are required.
Flame-Retardant Heat-Shrink Cable
Accessories
Specific environments such as railway, offshore
applications, government buildings, or power-
plant applications have requested flame-retardant
cables and cable accessories requirements.
Typical standards need to be met by cables.
The standards are IEC-60332 and IEEE-1202
and usually only refer to cables. However, it
has become common practice and industry-
understanding to qualify cables with cable
accessories to prove their suitability.
During the IEEE-1202 test, the flame is applied to
the cable or cable with accessory for 20 minutes.
After this time, the flame will be removed, and the
product characteristics need to assure that the
flame will self-extinguish. The damaged area or
flame propagation caused by this test shall be less
than 1.5m (such as in a vertical tray application).
The right material choice, which is usually
combined with a particular wall thickness in the
heat-shrink tube, will result in a flame-retardant
heat-shrink tube. Shown is a typical arrangement
where cables with flame-retardant heat-shrink
tubes are subjected (Figure 5).
