Cost-Conscious Buyers Match Cable Jackets to Applications

Basic protection, mid-range or premium jackets: Which one does your application need? Here’s help.

Cable jacket options can be perplexing, but in today’s economy, no one wants to pay for features they don’t really need. How do you know when basic PVC will handle your applications, and when you need to move up to more expensive protection? This summary may help with the choice.

PVC offers very high value

PVC jackets offer excellent value and deliver very high moisture resistance in general industrial applications – such as automotive – where environments are not overly harsh. Most 600V and medium-voltage power cable in industrial applications is protected by PVC jackets. Cost-conscious buyers specify PVC where they can, and move up to CPE (chlorinated polyethylene) when harsh conditions demand it.

CPE delivers increased protection for moderate price boost

Where environments contain oil, acids or alkalis, as in pulp and paper, CPE jackets give more protection than PVC for a moderate price premium.

For fire safety, CPE offers lower halogen content than PVC: 16 - 19 percent, where PVC runs 29 - 31 percent. In line with industry practice, Southwire’s CPEs and PVCs are thermoplastic with thermoset characteristics. In fire situations, they burn to an ash, with minimal dripping.

CPE displacing CSPE in many applications

CSPE (chlorosulfonated polyethylene – Hypalon®) is a premium-priced jacket designed to resist strong oil exposure in harsh petrochemical environments, but it exhibits high moisture absorption. That can expose cable insulation to moisture, and the absorbed moisture can combine with sulfur in CSPE to corrode the tape shield to copper sulfate (black copper). The corrosion weakens the tape shield mechanically and also degrades conductivity, which can reduce short-circuit capacity.

Today, for all but the most severe oil hazards, many cable buyers are moving to CPE, because it delivers similar protection – with lower moisture absorption – for a significant cost saving. CPE also offers a lower coefficient of friction than CSPE, which reduces pulling tension and the risk of cable damage. CPE looks better for cold-weather installation, too. It delivers low-temperature bendability down to -35° C, versus -30° C for CSPE.

Another lower-cost alternative to CSPE in petrochemical environments – for 600V cable tray applications – is PVC-Nylon Tray Cable (VNTC). VNTC uses THHN (PVC insulated, nylon-covered) conductors bundled inside a PVC jacket for multi-conductor power and control cables.

SOLONON offers premium protection, increased fire safety

Where a premium jacket is needed, SOLONON excels in moist environments. In duct banks and direct burial, for instance SOLONON offers much better moisture protection than CSPE, better tensile strength, and a lower coefficient of friction for less chance of cable damage during a pull.

In confined spaces where cable smoke may be a problem, such as tunnels, equipment vaults, control and switch rooms, SOLONON also adds fire-safety benefits to the mix. SOLONON has zero halogen content, and it passes UL’s tough Limited Smoke test, where CSPE doesn’t.

More cable jacket questions? Contact your Southwire representative to connect with Southwire technical support.

Typical Cable Jacket Applications

Material	Typical Applications	Characteristics	Cost
PVC	General industrial	very high moisture resistance, excellent cost-benefit	low
CPE	Harsh industrial	resistance to oils, acids and alkalis	moderate
CSPE (Hypalon)	Harsh petrochemical	high oil resistance; low moisture resistance	premium
SOLONON	Duct banks; direct burial, fire-safety environments	high moisture resistance; high strength, easy pulling; low-smoke; non-halogen	premium

For more complete cable jacket characteristics, refer to Q1, 2004 Power Cable Update at http://www.mysouthwire.com/.

Contact: Dave Cooper, Doug Ramsey