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/images/PowerCableUpdate.jpg/images/southwire_100x70.jpgERP Reliability Comes From Clean Compounds - November/December 2002ERPReliabilityComesFromCleanCompoundsNovandDec2002.htmKeeping EPR insulation free of contaminants is a key to reliable performance, because contaminants in insulation compounds can cause localized concentrations of electrical stresses. Enclosed manufacturing and blending processes produce . . .
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ERP Reliability Comes From Clean Compounds - November/December 2002

Keeping EPR insulation free of contaminants is a key to reliable performance, because contaminants in insulation compounds can cause localized concentrations of electrical stresses. Enclosed manufacturing and blending processes produce super-premium EPR compounds that contribute to Southwire's high cable reliability.

Contamination in medium-voltage power cable insulation is bad news. The voltage stresses that contaminants create can lead to premature insulation failures.

"For maximum reliability, medium-voltage insulation systems should generate a smooth gradient of electrical stress from conductor potential to ground," says Robert Fazio, Southwire director of industrial products and power generation. "Contaminants in insulation compounds can cause localized stress concentrations."

That's why Southwire uses EPR (ethylene propylene rubber) compounds that are blended under clean, contaminant-free conditions. Consistently contaminant-free compounds are vital to consistent long-term reliability from modern EPR insulation.

Super-premium compounds come from enclosed processes

"Since compound cleanliness and consistency are critical to reliability, Southwire uses super-premium EPR insulation compounds from a supplier recognized throughout the wire and cable industry for cleanliness, performance and properties," says Fazio.

Southwire's EPR insulation compounds are produced in a closed process that assures clean manufacturing. The process uses a dedicated production line, and it starts with ultra-fine filtering. All steps after the critical compound filtering use enclosed piping and processing equipment, and all air used for material transfer is filtered.

"The enclosed processes minimize the possibility of introducing contamination from the environment into the compound," Fazio says. "The result is an ultra-clean, consistent product."

Compound testing goes far beyond operating voltage stresses

In medium-voltage cables, maximum voltage stresses - which occur at the interface with the conductor shield - are typically less than about 64V/mil (2.5kV/mm). "Southwire EPR compounds are tested to 500V/mil (19.7kV/mm)," says Fazio. "That's nearly 10 times the expected maximum."

Fazio adds, "We're fanatic about insulation performance. It pays off in superior cable life. That's part of Southwire quality."

Southwire Insulation Performance Exceeds Industry Standards


Southwire medium-voltage ERP insulations meet or exceed industry standards including:

  • ASTM D-2802 and D-2770
  • ICEA S-68-516 / NEMA Pub. No. WC8
  • AEIC CS6
  • ANSI / ICEA S-94-649
  • IEC Publication 502
  • UL 1072 for type MV-90, MV-105