Insulation is a non-conductive material that protects and surrounds individual cables or wires that comprise a cable assembly. In electrical applications, several wire insulations are made to resist electrical currents, while some are used in radio frequency cable applications.

At MarVac Assemblies, we have established a credible history of providing customers with high-quality insulating materials and wire isolation services thanks to our offshore and custom production capabilities.

What Is Wire Insulation?

Insulation is an essential outer layer applied to wires and cables to protect them from external conditions. At the same time, it prevents electrical current leakage from the wires into the surrounding environment.

There are many different types of insulation materials used to make multiple kinds of cables, and one method for identifying the insulation type is through its electrical characteristics. Here are the four electrical elements that determine the type of insulation:

Dielectric Constant

The dielectric constant of a substance or material is the measure of its ability to store electrical energy. It measures how well a material holds or concentrates electric flux. In addition, a high dielectric constant is not always desirable. Materials with high dielectric constants degrade more quickly when exposed to extreme electric fields than substances with low constants.

Dielectric Strength

The dielectric strength of a material is the measure of the electrical power of an insulator. It is also referred to as the maximum voltage needed to cause a dielectric breakdown through the material and is expressed in volts per unit thickness. In other words, the higher the dielectric strength of a material, the better an electrical insulator it makes.

Dissipation Factor

The dissipation factor measures how inefficient a capacitor’s insulating material is. It also calculates the heat lost when an insulator is subjected to an alternating electrical field. Moreover, it follows the rule that a material with a low dissipation has excellent efficiency.

Insulation Resistance (IR)

An insulation resistance (IR) test measures the total resistance value between any two points separated by electrical insulation. It also determines the dielectric’s (insulation’s) ability to resist the flow of electrical current.

Why Is It Important To Insulate Wires?

The significance of insulated wiring cannot be neglected, as it protects the wiring from damage and the hazards of the external environment. Aside from that, the most common reasons are as follows:


Electrical wire insulation is critical for keeping an area safe and preventing electric shock. Additionally, electrical hazards are defined by the Occupational Safety and Health Administration (OSHA) as exposed wires, worn insulation, and removed insulation.


Wiring is made of metals that can corrode with exposure to water, and insulation protects materials like copper and steel from the elements, allowing them to withstand their surroundings and last longer. In addition, wiring that is not insulated will only last for a short time.

Leakage Prevention

Electrical leakage happens when energy transfers to components such as the framework or other wires. With that, insulation keeps wires from touching and contacting framework or grounding materials.


For consistency, electrical wires are color-coded according to specific standards. This color-coding method facilitates the identification, which helps electricians and other handlers do their jobs more efficiently. The following are some of the more popular colors used in the market:

  • White: 14-gauge wires rated for 15 amps
  • Gray: cables rated for 15 amps
  • Black: six- and eight-gauge wires rated for 40-60 amps
  • Orange: 10-gauge wires rated for 30 amps
  • Yellow: 12-gauge wires rated for 20 amps

What Are the Different Types & Applications of Wire Insulation?

Insulation is typically made of plastic, fluoropolymers, or rubber, depending on the requirements and applications.


Polyvinyl Chloride (PVC)

PVC is well-known for its diverse applications, especially in the medical and food industries. It is resistant to flame, moisture, and abrasion and has a temperature range of -55°C to 105°C. Moreover, its applications suit gasoline, acids, solvents, and ozone.

Semi-Rigid PVC (SR-PVC)

SR-PVC is utilized as the predominant insulation where abrasion resistance is required. It is also resistant to flame, water, acid, and alkali.

Plenum Polyvinyl Chloride (Plenum PVC)

Plenum PVC is appropriate for interiors with air circulation beneath raised floors or above-dropped ceilings.

Polyethylene (PE)

Polyethylene is a dense, rigid material that primarily insulates coaxial and low-capacitance cables. Though flammable, it has excellent electric properties, can lower the dielectric constant, and is the ideal choice for lines requiring high-speed transmission.

Polypropylene (PP)

Polypropylene has properties similar to polyethylene, with a temperature range of 30°C to 80°C. Therefore, it is commonly used in interiors, particularly within thin walls.

Polyurethane (PUR)

Polyurethane is a flexible material that can withstand temperatures ranging from -62°C to 93°C. Thus, it is suitable for retractile cord applications and marine and low-temperature environments.

Chlorinated Polyethylene (CPE)

CPE is highly resistant to heat, oil, and water and is commonly used in power and control cable applications, industrial power stations, and CPE cable insulation displays.


Nylon is well-known for its flexibility and resistance to chemicals, cut-through, and abrasion. It is also typically extruded over softer insulation compounds.


Thermoplastic Rubber (TPR)

TPR has good heat, weather, and age resistance but has poor cut-through tolerance. As a result, it is used in applications requiring faster processing speeds and a wider operating temperature range.

Neoprene (Polychloroprene)

Neoprene is a thermoset rubber resistant to abrasion, cut-through, oil, and solvents. It also has high durability and a wide temperature range.

Styrene Butadiene Rubber (SBR)

SBR has properties similar to neoprene but with a temperature range of -50°C to 90°C. It is primarily used in Mil-C-55668 cables used for operations at audio frequencies requiring a high degree of flexibility.


Silicone is a versatile synthetic rubber with high heat resistance and flame retardancy (180°C). It is also highly flexible and has good abrasion resistance, making it suitable for electrical applications.

Ethylene Propylene Rubber (EPR)

EPR has excellent thermal and electrical properties and is commonly used in high-voltage cables. The material is soft and flexible, with an operating temperature range of -50°C to 160°C. It is also highly resistant to heat, oxidation, water, acid, alcohol, and alkali.

Chlorosulfonated Polyethylene (CSPE)

CSPE or Hypalon delivers low-voltage insulation with resistance to chemicals and UV. It is commonly found in appliance wires, lead wires, coil leads, transformer leads, and motor lead cables.

Ethylene Propylene Diene Monomer (EPDM)

EPDM is resistant to heat, ozone, weather, and abrasion. It also has good electrical properties and dielectric strength while retaining flexibility in temperatures ranging from -55°C to 150°C.


Perfluoroalkoxy Alkane (PFA)

PFA is a costly material used in both high and low-temperature applications. Also, it has high mechanical strength and a low dissipation factor, making it an electrically efficient choice.

Polytetrafluoroethylene (PTFE)

PTFE is a thermoplastic material that is highly flexible and resistant to water, oil, chemicals, and heat. Its applications operate at temperatures ranging from -73°C to 204°C.

Fluorinated Ethylene Propylene (FEP)

FEP is a flame-resistant material widely used in plenum cable and military applications. Foaming improves data transmission, which in turn enhances pricing and processing.

ETFE and ECTFE Halar

ETFE and ECTFE Halar materials are stronger and more flexible than PFA or FEP and can become thermoset when ionized. In addition, the material is foamed to reduce weight and improve data transmission. However, they do not have the electrical benefits that FEP does.

Polyvinylidene Fluoride (PVDF)

PVDF, also known as Kynar, is a low-cost, flexible, lightweight, and thermally stable insulation material resistant to chemicals, heat, weather, abrasion, and fire.

Custom Wire Processing From MarVac Assemblies

MarVac Assemblies has wire processing equipment for all types of insulated wire. We can work with solid or stranded wire in gauges ranging from 2 to 24 AWG. Furthermore, we are equipped with high-quality custom wire processing equipment and harness services that comply with WHMA/IPC-A-620 industry standards.

Our equipment and assembly processes are applied to a wide variety of assembled products, including the following:

  • Power sources
  • Heaters
  • Lighting fixtures
  • Refrigeration apparatus
  • Off-road vehicles
  • Printed circuit boards
  • Electrical system assemblies

We also provide a wide range of wire processing services, such as cutting, marking, stripping/retaining, twisting, crimping, and terminating ends.

Contact MarVac Assemblies For Your Wire Processing Needs!

MarVac Assemblies specializes in high-quality electronic components and value-added services that we customize to suit our customers’ needs! We also offer a wide range of assembly services, product modification solutions, and inventory management programs, which can reduce acquisition costs, optimize procurement, and minimize production liability.

To know more about our products and services, contact us now!