Cable Sheath Materials - What You Need to Know

Question

Insulation and sheath are the components of a cable that protect the conductor. The insulation isolates the flow of electricity, and the sheath wraps around the outside of the cable to protect the conductors inside. The choice of material used for insulation and sheath can have a significant impact on the overall performance of a cable. The following will provide you with an overview of the most common materials used in cable manufacturing.

 

PVC (Polyvinyl Chloride) – For internal installations.Polyvinyl Chloride (PVC)

PVC is the most common and cheapest option for a given cable yarn design, it offers good flexibility, low cost and reasonable durability. It also offers good resistance to oil and water. The disadvantages are that some grades of PVC can weather badly and are susceptible to UV light. It can also give off poisonous halogen gases, toxic fumes and smoke when burnt. 

 

PE (Polyethylene) – For external installations.

PE can be stiff and very hard, however low density PE (LDPE) is more flexible. If it’s UV stabilized it offers excellent moisture and weather resistance. Often referred to as duct grade or weather resistant, high density PE sheath material (HDPE) can offer a good option for external or direct burial applications.

 

LSF (Low Smoke & Fume)

A modified PVC compound which can produce less HCI gas and smoke than PVC cables. However, LSF is a somewhat meaningless term, because it is PVC based it could still emit up to 22% Hydrogen Chloride (HCl) gas when burnt and give off black smoke. By way of comparison, standard PVC gives off up to 28% HCl.