NEMA publishes WC 70
By Anthony Capkun
The National Electrical Manufacturers Association (NEMA) has published ANSI/NEMA WC 70/ICEA S-95-658 “Power Cables Rated 2000 Volts or Less for the Distribution of Electrical Energy”—the first revision since 1999. The standard was produced by Insulated Cable Engineers Association (ICEA) Working Group 658 and approved by the NEMA Power and Control Cable membership.
WC 70 contains all construction requirements for the manufacturing of
wire and cables, both single- and-multiple conductor, as well as
production and qualification testing requirements. Special requirements
for grounding conductors, when shielding is required, and
messenger-type cables are also included.
The publication has been technically and editorially brought up to date. Revisions include:
• Added text and a new table for grounding conductors.
• Information regarding use of shielding over a low-voltage, multiple-conductor cable core.
• Low-smoke, zero-halogen jacket requirements.
• A new appendix, “Procedure for Determining Dimensional Requirements of Jackets and Associated Coverings”.
• Requirements of insulation and jacket thickness changed to minimum
point, with the thickness tables changed accordingly. Nominal thickness
for insulations and jackets has been added to the appropriate tables in
Sections 3 and 4. A clarification has been added that the nominal
thickness is not a requirement, making this standard agree with ICEA’s
other low-voltage standards.
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