Cable Jacket Materials Explained: PVC, LSZH, PUR and PE Compared

Cable performance is decided as much by what surrounds the conductor as by the metal inside it. The jacket, or outer sheath, protects the core against heat, abrasion, chemicals, moisture, UV exposure and mechanical abuse, and it strongly influences how a cable behaves when something goes wrong. Choosing the wrong compound can mean a cracked sheath in a cold store, a jacket that turns brittle after a summer in direct sun, or a smoke-filled stairwell during a fire.

Four jacket materials account for the great majority of industrial and commercial cable: PVC, LSZH, PUR and PE. They are not interchangeable, and the right answer depends on the environment the cable will actually live in.

PVC (Polyvinyl Chloride)

PVC is the default general-purpose jacket. It is inexpensive, easy to process, reasonably flexible and offers decent resistance to oils, acids and alkalis. That combination makes it the material most people picture when they think about electrical cable.

• Temperature range: typically -15 °C to +70 °C, with special formulations reaching +105 °C for short periods.
• Abrasion and oil resistance: moderate; fine for dry indoor wiring, less suited to repeated dragging or constant flexing.
• Fire behaviour: PVC is inherently flame-retardant because of its chlorine content, but when it burns it releases dense black smoke and corrosive hydrogen chloride gas.
• Flexibility: high, which suits tight bends and small enclosures.
• Typical use: fixed indoor installation, control panels, domestic and light commercial wiring and low-cost signal cable.

LSZH (Low Smoke Zero Halogen)

Low smoke zero halogen compounds are built on halogen-free polymers such as cross-linked polyethylene or special thermoplastic blends, with mineral fillers added for flame resistance. The whole point of the formulation is what happens in a fire: an LSZH jacket releases very little smoke and no halogen acids, so people can see their way out and equipment is not corroded by acidic fumes.

• Temperature range: commonly -30 °C to +90 °C, with cross-linked grades rated higher.
• Fire behaviour: low smoke emission and zero halogen release, with combustion gases of low toxicity.
• Abrasion and oil resistance: fair to good; adequate for trays and conduits, but less tough than PUR where the cable moves.
• Flexibility: moderate; stiffer than PVC or PUR, so minimum bend radii must be respected.
• Typical use: crowded public buildings, metro and underground rail tunnels, data centres, hospitals, airports and ships.

In these locations the requirement is not just a preference. Building codes and rail standards increasingly mandate halogen-free, low-smoke cable in escape routes, tunnels and rooms holding critical equipment, because the acid gases from a PVC fire can destroy servers, switchgear and control systems even in rooms the flames never reach.

PUR (Polyurethane)

Polyurethane jackets are the choice where the cable has to survive movement. PUR is tough, cuts and tears reluctantly, and stays flexible at temperatures that would leave other compounds stiff and brittle.

• Temperature range: roughly -40 °C to +90 °C, remaining flexible well below freezing.
• Abrasion resistance: excellent, among the highest of the common jacket materials.
• Oil and chemical resistance: very good, including against many cutting fluids and hydraulic oils.
• Notch and tear resistance: high, which matters in drag chains and robotic arms.
• Typical use: continuous-flex robotic cable, drag chains, festoon systems, machine tools, mining and heavy mobile equipment.

PE (Polyethylene)

Polyethylene is a tough, low-cost and chemically inert polymer. It is not the most flexible jacket, but its outstanding moisture resistance is why it dominates outdoor and buried cable.

• Temperature range: roughly -40 °C to +80 °C, depending on grade.
• Moisture resistance: excellent; PE is one of the best low-cost barriers against water ingress.
• Chemical resistance: very good against acids, alkalis and many solvents.
• UV resistance: poor unless carbon black is compounded into the jacket, so black PE is the standard for outdoor service.
• Flexibility: low; PE is stiff and generally used where the cable is fixed in place.
• Typical use: outdoor and direct-burial power and telecom cable, duct installations and underground runs.

Comparing the Four at a Glance

One More Check Before You Specify

A cable is not a single material. The jacket and the insulation around each conductor are chosen separately and are often different: a halogen-free LSZH jacket may sit over PVC-insulated cores, and a rugged PUR outer sheath may protect polyethylene-insulated data pairs. A jacket described as low smoke does not automatically mean the whole cable is halogen-free.

When selecting a cable, confirm both layers against the real conditions — temperature, flexing, chemicals, moisture and fire regulations — and verify the finished assembly rather than reading one line of a datasheet. Getting the jacket right is what keeps a cable working after the first hot summer, the first cold winter and the first accident.