Types of Electrical Cable Insulation and Their Applications Explained
What Is Insulation?
Insulation is an important part of any electrical cable — it is made of a non-conductive material and covers the wire. It is also called an electrical insulator.
The purpose of insulation is to separate the current from other parts of the cable to keep the electricity within the wire and prevent it from accessing the surrounding environment. At the same time, insulation protects the wire from harsh conditions in the environment where it is installed and ensures its proper functioning.
Insulation can be made of different materials depending on what the wire's targeted application is. But overall, plastic, rubber and fluoropolymers are the most common wire insulation types.
Plastic Insulation
Polyvinyl chloride (PVC)
PVC is resistant to moisture, flame and abrasion and can be used in lots of environments: acids, solvents and ozone. PVC-insulated cables also have no taste or odor, therefore they are not toxic. The allowable temperature range for this material is from -55°C to 105°C.
Semi-rigid (SR) PVC
SR-PVC has similar resistance characteristics to PVC insulation, but this one works better when maximum resistance to abrasion is the priority.
Plenum PVC
Plenum PVC is also made of polyvinyl chloride but is best suited for installations in indoor areas with air circulation, like raised floors or dropped ceilings.
Polyethylene (PE)
PE is an inflexible material used when high-speed transmission and low capacitance are needed. PE is also a go-to cable insulation option for coaxial wires. The material is resistant to soldering, cracking and solvents, with an operating temperature ranging from -65°C to 80°C. XLPE (cross-linked polyethylene) insulation is a commonly used subtype of PE insulation.
Polypropylene (PP)
PP has similar characteristics to PE but is mostly used in indoor environments. The allowable temperature range for this insulation material is 30°C-80°C.
Polyurethane (PUR)
PUR is a flexible material mostly used for electrical cables targeted for low-temperature and marine environments. It is resistant to moisture, chemicals and abrasion, and its operating temperature ranges from -60°C to 90°C.
Rubber Insulation
Thermoplastic rubber (TPR)
TPR is resistant to heat and harsh weather conditions and is the best fit for when a high processing speed is required.
Neoprene (Polychloroprene)
Neoprene is resistant to abrasion, oils and solvents. This insulation material makes an electrical cable long-lasting.
Ethylene propylene rubber (EPR)
EPR is widely used for high-voltage cables — it is flexible and resistant to most irritants. The allowable temperature range for EPR cable insulation is from -50°C to 160°C.
Ethylene propylene diene monomer (EPDM)
EPDM is resistant to harsh weather conditions, heat and abrasion while also being a strong dielectric and flexible. Its operating temperature ranges from -55°C- to 50°C.
Silicone
Silicone is a widely used flexible synthetic rubber insulation. This one is especially useful in high-heat areas since it withstands temperatures up to 180°C.
Fiberglass
Fiberglass is resistant to moistures and chemicals. With a maximum operating temperature of 482°C, this glass insulation is often used in kilns, aluminum processing and heat treating.
Styrene-butadiene rubber (SBR)
SBR has similar characteristics to neoprene but is mostly used for Mil-C-55668 cables.
Fluoropolymers Insulation
Perfluoroalkoxy (PFA)
PFA is a strong and therefore, durable insulation material for use in extreme temperatures (from -65°C to 250°C).
Polytetrafluoroethylene (PTFE)
PTFE is a flexible thermoplastic material that is resistant to heat, oils, moistures and chemicals. The allowable temperature range for this one is from -70°C to 205°C.
Fluorinated Ethylene Propylene (FEP)
FEP is often used in plenum and military cables because of its high resistance to flame and excellent data transmission capabilities.
Polyvinylidene Fluoride (PVDF)
PVDF is also known as Kynar — it is resistant to most irritants, including flame. It is also flexible and not heavy, which makes it a good fit for indoor environments with air circulation.
Choosing the Right Cable Insulation
The type of insulation you choose depends on the target application of your cable. At Nassau National Cable, we have wires with all types of insulation with both aluminum and copper conductors. For example, some of our most popular products are THHN THWN-2 Aluminum Cable with PVC insulation and Copper Service Entrance Cable (SEU) with XLPE insulation. Browse through our catalog to see more products and find the electrical wire you need for your project.
