Of all the chemical exposures that can affect the life and
performance of electrical cables, oil is one of the most
damaging. Used as a coolant and lubricant in many industrial and
infrastructure settings, oil can inflict molecular damage on the
polymers used for cable insulation and jacketing.
If ignored, oil damage to cables can be severe. It will ultimately
result in cable failure, downtime and replacement costs.
Awareness of oil damage has been on the upswing in recent years,
thanks to regulatory changes and the increased performance
characteristics in renewable energy, automotive assembly and other
advanced production facilities.
Fortunately, there are cables that have been designed from the
ground up to resist the effects of cooling and lubricating oils.
Oil can cause polymers, such as those used for cable insulation and jacketing, to
degrade and crack. Selecting an oil-resistant cable is the best way to avoid this
failure mode.
vary greatly, depending on the desired properties and applications.
These properties can be achieved by adjusting the formulations
of a particular PVC compound. The modification or addition of
flame-retardants (iodine), stabilizers, and fillers allow the compound
to exhibit these types of enhanced characteristics. However,
Here’s a closer look at how oil degrades cables, how to diagnose oil
when certain PVC characteristics are improved, the enhancement
exposure problems and how to select cables that can stand up to
oils over the long haul:
DEGRADATION MECHANISM
Why does oil cause such excessive damage on some types of
insulations and jackets, while others are more resistant? The
main reason is that not all polymer compounds offer equivalent
performance even if they have the same family name. This is true
for many physical properties, including oil resistance.
sometimes comes at a cost, the cost being that other performance
traits are affected or completely lost.
With oil resistance in particular, all wire and cable insulations
are not created equal. Electrical, environmental, mechanical,
and chemical attributes will vary depending upon the individual
compound formulations. Insulating compounds contain a specific
amount of plasticizers in their individual formulations, which help
promote flexibility and resistance to fatigue. When compounds are
exposed to lubricating and coolant processing oils the material
For example, some PVC compounds have a higher degree of flame
resistance, while others have better oil resistance. Still others
demonstrate improved flexibility characteristics. PVC formulations
either absorbs the oil or the plasticizer will diffuse from the
compound.
