Oil Resistant Wire, Cable, and Electrical Connectivity Equipment

Oil Resistant Wire, Cable, and Electrical Connectivity Equipment

Oil Resistant Wire, Cable, and Electrical Connectivity Equipment

Written By: LAPP Tannehill

Oil-resistant wire, cable, and connectivity solutions need to be considered in industrial settings to decrease maintenance costs, machine downtime, and more.


The usage of industrial oils in modern manufacturing and commercial applications is increasing at a fast pace.

As industrial processes advance in capability and complexity, the world’s leading petrochemical companies are on an unending quest to push the limits of petrochemical polymer technologies to keep pace with today’s industrial economy.

With this rapid proliferation of industrial oils comes the risk of potential oil-related damage to the electrical and communications infrastructure that forms the backbone of modern industry.

The resultant impact to throughput, uptime, and repair/replacement costs can have substantial impact to business results if important electrical design and selection considerations are not factored in.

 

Industrial Oils and Their Impact to Wire, Cable, and Electrical Connectivity Equipment

Industrial oils are broadly used in a variety of industrial sectors including most types of manufacturing plants, agriculture and construction, food processing, textiles, building materials and so on.

These oils are often used for lubrication and wear protection for many types of machinery and equipment with moving parts where they can protect against fatigue and oxidation in addition to normal mechanical wear and tear.

Oil used in CNC Machining in an industrial setting on a manufacturing floor presumably around electrical equipment

Industrial oils can also be used as a coolant to avert thermal degradation in processes such as machining operations and other applications where mechanically induced friction can cause unwarranted rise in equipment and local ambient temperature.

Lastly, hydraulic oil is a specialized oil that also serves as a power transfer mechanism in hydraulic power systems.

Hydraulic oil requires a high bulk modulus (i.e. a low reduction in volume under pressure in order to transfer hydraulic power) and a high viscosity index (i.e. a fairly constant viscosity as temperature changes in order to maintain a relatively consistent level of hydraulic power transfer). 

Regardless of the type of industrial oil or its intended application there is always a risk of it coming into physical contact with electrical infrastructure such as wire, cable, cord grips, connectors, tubing and sleeving or other wire/cable management equipment.

Unless specific oil-resistant design and selection criteria are factored in well ahead of installation, companies cannot be guaranteed that wire, cable, and electrical connectivity equipment will reliably and consistently operate over time.

Potential oil damage to critical electrical and communications infrastructure can reduce process efficiencies and ultimately lead to avoidable downtime and unacceptable replacement costs.

Wiring, cabling, cord grips, connectors and other electrical products are all designed to be “fit for purpose” in multiple dimensions including electrical, mechanical, chemical, and other physical attributes.

For example, a certain type of cable may be specifically intended to function up to 105C (221F) in ambient temperature, have specific electrical insulation characteristics for its jacket construction, and maintain a certain amount of flexibility amongst many other attributes to function successfully over time in a specific application (e.g. for use in a continuously moving cable chain).

When the electrical equipment is exposed to any form of industrial oil some of it is absorbed into the plastic or other materials of construction for the equipment.

This oil absorption can oftentimes change the resultant physical attributes of the material, which in turn could degrade the designed-in performance characteristics of the equipment in question.

For example, please reference this article on the impact of oil onto cabling by LAPP. 

Protecting Electrical Connectivity Equipment from Oil: Material Selection + Testing

Protecting electrical connectivity equipment from the harmful effects of industrial oils mainly involves the appropriate selection of wire, cable, connectors, and cord grips during the design and procurement phase of a project.

Specific oil resistance testing is also conducted to ensure industry standards where applicable.

Materials Selection for Oil Resistance

The most fundamental method for avoiding oil-related degradation is proper materials selection.

Engineering and procurement departments must factor in potential exposure to industrial oil before selecting their electrical connectivity products regardless of whether oil exposure is a normal every-day occurrence in an application (i.e. in and around machining equipment or wind turbines) or only presents risks during extreme / periodic situations.

Table 1 provides a qualitative comparison of the oil resistance for various polymer materials of construction, including plastics, fluoropolymers, and rubber materials.

Note that these qualitative ratings are based on the average oil performance of general-purpose compounds. Many manufacturers can provide improved oil-resistance performance via the use of selectively specified and engineered compounds.

TABLE 1: Oil Resistance Ratings for Common Materials

Plastics Rating
Low Density PE 3 to 4
High Density PE 3 to 4
Nylon 4
Polypropylene 2
PVC 2
PUR 4
Fluoropolymers Rating
FEP 5
PTFE 4 to 5
ETFE 4
ECTFE 5
PVDF 4
TPE 3
Rubber Rating
Rubber 1
Neoprene 3
EPDM 1
Silicone 2-3

Rating Scale: 1 Poor; 2 Fair; 3 Good; 4 Excellent; 5 Outstanding

While multiple factors will determine the speed and severity of oil damage to various materials (including temperature, exposure duration, amount of oil, type of oil) in general the higher-rated materials will have a stronger resistance to deterioration.   

Oil exposure can impact materials in several ways as it is absorbed into the materials of construction for electrical connectivity equipment. 

  • First, this oil absorption can cause volumetric changes (greater volume or “swelling”) as the oil is incorporated into the material.
  • Second, the oil absorption can lead to changes in the hardness changes of the material (as defined by any number of objective hardness testing methods such as the Rockwell, Vickers, Knoop or Brinell hardness tests commonly utilized by materials science engineers).
  • Third, the oil absorption can lead to changes in the chemical compound comprising the material itself.

Regardless of which of the 3 (or all 3) ways oil exposure can impact the electrical equipment’s materials, the net result is a potential compromise in performance.

For example, some cable jacket and insulating compounds utilize very specific and proprietary plasticizer materials (oftentimes a solvent) to help improve plasticity, which in turn improves cable flexibility and durability with flex cycles.

With the introduction of a foreign substance such as industrial oil these plasticizers are susceptible to diffusion from its original compound thereby compromising its flexibility properties.

Wire, cable, connectors and wire management equipment can all be compromised in similar ways due to oil exposure and the proper selection of materials of construction is the first line of defense against oil damage.

Testing for Oil Resistance

In addition to proper materials selection, a fundamental understanding and awareness of applicable industry-standard oil exposure and resistance testing can also be helpful.

For example, Table 2 outlines a few US/Canadian and European industry standards related to testing wire and cable versus oil exposure to be aware of.

These standards have varying levels of oil exposure (duration and temperature) as well as different post-test requirements.

It is important to be aware that these standardized industry tests typically use standardized test oils that cannot be entirely representative of the entire spectrum of industrial oils in existence.

Therefore, it is important for designers, installers and users of electrical connectivity equipment consult with the manufacturers and distributors to ensure the proper product is selected.

TABLE 2: Industry Standard Oil Resistance Tests for Wire and Cable

Industry Standard # Industry Standard Title Region Immersion Duration Immersion Temperature Requirement: Tensile Strength Requirement: Elongation
UL 62 Flexible Cords and Cables US/Canada 7 Days 60°C 75% retention of unaged tensile strength 75% retention of unaged elongation
UL Oil Res I UL Oil Resistance I US/Canada 4 Days 100°C 50% retention of unaged tensile strength 50% retention of unaged elongation
UL Oil Res II UL Oil Resistance II US/Canada 60 Days 75°C 65% retention of unaged tensile strength 65% retention of unaged elongation
UL AWM 21098 Multiconductor Cable with Extruded Non-Integral Jacket US/Canada 60 Days 80°C 65% retention of unaged tensile strength 65% retention of unaged elongation
EN 50363-10-2 Insulating, sheathing, and covering materials for low voltage energy cables; Part 10-2: Miscellaneous sheathing compounds - thermoplastic polyurethane Europe 7 Days 100°C Max deviation of tensile strength: ± 40% Max deviation of elongation at tear ± 30% (min 300% effective)
EN 50290-2-22 Communication cables; Part 2-22: Common design rules and construction - PVC sheathing compounds Europe 4 Hours 70°C Max deviation of tensile strength: ± 30% Max deviation of elongation at tear ± 30%
EN 50363-4-1 Insulating, sheathing, and covering materials for low voltage energy cables; Part 4-1: PVC sheathing compounds Europe 7 Days 90°C Max deviation of tensile strength: ± 30% Max deviation of elongation at tear ± 30%

Oil Resistant Wire

Oil resistant wire is available in many types, insulation compounds and application-specific designs. 

For example, in transportation applications, most types of automotive primary wire (i.e. GXL, SXL, TXL, SGX, etc…) provide a good level of oil resistance as some of these wire types can be used in the engine compartments of motor vehicles, thereby subjecting them to potential oil exposure.

Silicone wire is a high-performance wire suitable for many challenging industrial applications. Silicone rubber has a high degree of chemical inertness (it belongs to the inert polymer category) and as a result has a quite high resistance to absorption of industrial oil.

Among common organic rubbers, nitrile rubber and chloroprene rubber have somewhat higher oil resistance at temperatures below 100°C, but at higher temperatures silicone rubber is superior.

The LAPP ÖLFLEX® HEAT 180 line of silicone wire as well as Alphawire’s series of UL3212, UL3213, UL3214 and UL3239 silicone hook up wire are two examples of wire to consider for industrial applications requiring a higher level of oil resistance than standard PVC wiring.

Lastly, many XLP insulated wires such as UL3271 XLPE can also have higher resistance to the effects of industrial oils over standard PVC wiring.

Oil Resistant Cable

Protecting multiconductor electrical cable in industrial applications from the harmful effects of oil is a very common challenge in modern industry.

Not only is it a challenge due to the previously mentioned widespread use of industrial oil, but also due to the increasing proliferation of cable use-cases requiring cable flexibility for motion and dynamic applications requirements.

Any reduction in flexibility can compromise the cable’s intended fit-for-purpose.

LAPP Oil Resistant Cable with oil spilling over cable

PVC (polyvinyl chloride) cable is the most used cable in many industrial applications as it covers typical temperature requirements and has a good resistance to most chemicals. (Note: PVC is the world’s 3rd most widely produced synthetic polymer of plastic).

Unfortunately cables with a PVC outer sheath are, in general, not particularly resistant to oil per their standard formulation (chemical compound composition).

See this article from LAPP on the topic of oil-resistant cable and more specifically the impact of oil on PVC.  The PVC outer jacket of the cable is susceptible to oil absorption, thereby changing its chemical composition and harming its intrinsic properties (including flexibility). 

The best approach to combat the impact of oil on cabling is to either utilize specially enhanced PVC formulations or to transition away from PVC to higher performing jacketing materials altogether.

Select manufacturers of high-performing cable products have been able to engineer PVC compounds with special additives that enhance the PVC’s oil resistance characteristics while still retaining the many positive aspects of PVC.

For example, LAPP’s ÖLFLEX® 191 series of multi-conductor cable possess a PVC outer sheath with special chemical additives to enhance its oil resistance performance.

The  ÖLFLEX® 890 series is designed and constructed for heavy duty continuous flex applications where its specially formulated PVC construction provides superb resistance to mineral oils, synthetic oils, and water-based coolants.

Alphawires’s Xtra-Guard®1 multiconductor cable is a control cable with a premium-grade PVC insulation and jacket that provides UL Oil Res I/II oil resistance.

Moving away from PVC, leading manufacturers have implemented other thermoplastic polymer compounds as well as thermoplastic elastomer (TPE) compounds for cable jacketing materials in the quest for improved oil resistance performance.

LAPP’s ÖLFLEX® 190 is a flexible multi-conductor power and control cable and ÖLFLEX® TRAY II industrial-grade tray cable both utilize specially formulated thermoplastic polymer jackets and achieve Oil Res I and II oil resistance performance levels.

Alphawire’s Industrial Series cable lineup features several products featuring TPE oil-resistant jackets for stationary control applications (Alphawire Industrial Series P), continuous flex control applications (Alphawire Industrial Series F) and servo applications (Alphawire Industrial Series SF). 

Finally, the use of polyurethane jackets (PUR) provide a strong balance of flexibility, high oil resistance and robust abrasion-resistance.

LAPP’s ÖLFLEX® 409P/409CP and ÖLFLEX® 490P/490CP flexible power and control cable, as well as ÖLFLEX® 590P/590CP flexible heavy duty indoor/outdoor product lines are exemplary examples of oil-resistant PUR cable.

Oil Resistant Heat Shrink Tubing and Sleeving

Heat shrinkable tubing products are very commonly used wire management technologies commonly deployed in many applications.

Heat shrink tubing can be utilized to provide electrical insulation, physical protection and chemical resistance for electrical wires, joints/terminations, and splices as well as for bundling loose wires.

Due to its wide range of applications heat shrink tubing will often be required to provide some level of oil resistance.

As described previously, material selection is the primary determinant of oil-resistance performance for electrical connectivity products and heat shrink tubing is no exception.

Heat shrink tubing can be constructed of many different material formulations, the most popular being PVC and polyolefin compounds, as well as a wide range of other materials.

Additionally, for further protection consider dual-wall adhesive lined heat shrink tubing that provides both an inner and outer layer of protection. So even if the outer layer gets damaged, your system is still protected from exposure.

PVC Heat Shrink Tubing Samples

PVC Heat Shrink Tubing

PVC-based heat shrink tubing is a very widely used, economical tubing that is recommended where wide operating ranges of polyolefin are not required.

In automotive applications PVC heat shrink can be found in the instrument panel and vehicle interior wiring while polyolefin heat shrink can often be found under the hood around the engine.

While PVC is typically not recommended for applications with high exposure to oil, special formulations of PVC heat shrink will provide a level of oil resistance to otherwise exposed electrical connections.

For example Insultab’s HS-105 PVC 2:1 Shrink Ratio heat shrink tubing has a low shrink temperature, is highly flame retardant and provides resistance to many chemicals and oils including chlorinated cleaners, lubricating grease, penetrating oils, and electrical insulation oils.

Polyolefin Heat Shrink Tubing

Polyolefin-based heat shrink tubing has a wider operating temperature than PVC. Due to its relative chemical inertness polyolefin heat shrink can provide a good level of protection versus the effects of oils.

Dunbar 1635F 2:1 Shrink Ratio and 3635 3:1 Shrink Ratio heat shrink tubing for example provide a good combination of high resistance to abrasion, chemicals and oils.

For higher levels of oil resistance look to Dunbar DR150 (Diesel Resistant with 150˚C temperature rating) which is comprised of a flexible elastomer polyolefin construction that is resistant to lubrication oils, hydraulic fluids and aviation/diesel fuels.

Other Heat Shrink Tubing

Many other heat shrink materials beyond PVC and polyolefin are available for oil resistant applications.

For example, Viton™ heat shrink tubing is made from a unique fluoroelastomer material (i.e. synthetic rubber) that is resistant to high temperatures and remains flexible even at low temperatures while forming an effective seal against oils, fuels and lubricants.

3M has several types of special purpose heat shrink tubing with excellent oil resistance including 3M MFP (Polyvinylidene Fluoride transparent tubing), 3M NST (Modified Neoprene abrasion resistant tubing), 3M VTN-200 (Fluoroelastomer tubing for high temperatures), and 3M PSTH (Flexible Elastomeric Polyester tubing for harsh operating conditions).

TE Connectivity’s Raychem NT heat shrink tubing features a modified elastomeric construction that remains flexible at low temperatures and provides resistance to most fluids and solvents. TE’s Raychem SFR heat shrink has a silicone elastomer construction for excellent resistance to hydraulic fluids, fuel, and lubricating oil while providing very good ablative characteristics.

Oil Resistant Sleeving

Braided sleeving products are very commonly used for cable and wire management, particularly for the harnessing of multiple cables (including connectors) to help with bundling, abrasion protection, and routing through tight spaces.

Hands pulling apart Techflex expandable sleeving to show how cables fit inside

The bundling, abrasion resistance, and flexibility properties of braided sleeving products may be compromised if the correct sleeving materials of construction are incompatible with oils present in the operating environment.

For example, most of Techflex’s entire lineup of PET (polyethylene terephthalate, more commonly known as polyester) products including Techflex Expandable Sleeving and Techflex Wrappable Split Sleeving provide excellent resistance to the effects of oil exposure as polyester has excellent resistance to most substances including oils, hydrocarbon fuels and lubricants.

Specifically, Techflex’s PET products are unaffected when exposed to MIL-H-5606 (mineral-oil based hydraulic fluid) and MIL-L-7808 (aircraft turbine engine lubricating oil with a synthetic base).

Techflex’s nylon-based products also show similar high resistance to the effects of oil. 

Oil Resistant Cord Grips, Cable Glands, and Connectors

A complete oil-resistant electrical connectivity subsystem of wires, cables, tubing, and sleeving would not be complete without cord grips and connectors at the termination points that are equally up to the task of harsh industrial environments.

As with all other components discussed so far connectors (both circular connectors and rectangular connectors) and cord grips are considered oil-resistant if the materials used in the plastics of the products cannot react chemically with oils. 

For example, LAPP’s SKINTOP® ST-M cord grip series features an increased oil-resistant plastic cable gland with permanent vibration protection and reducing seal insert, providing  proven functional reliability even in demanding machine and plant cleaning processes.

The SKINTOP® ST-M features a polyamide construction which is extremely resistant to hydrocarbons such as fuels, oils, and greases.

Illustration of LAPP SKINTOP cord grip used with LAPP OLFLEX cable to secure cable
Please reference the following link for a broad array of cord grip solutions for every cable application. 

Conclusion: An Oil Resistant Electrical System is Only as Effective as the Sum of its Parts

The growing popularity of oil resistant electrical equipment requires today’s engineers, installers, and contractors to up their game when it comes to the design and selection of wire, cable, tubing, sleeving, cord grips and connectors.

Careful attention must be paid to materials of construction (and compatibility) and testing standards earlier on in the design/build cycle to ensure suitable fit-for-purpose performance of the entire electrical connectivity system over time.

A system is only as strong as its weakest component and success begins with awareness that oil resistant performance must be designed in from day one.

Reach out to us if you think you'll need oil-resistant wire, cable, or electrical connectivity equipment for your next project.

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