Cold Nights are Coming; Watch Installation Temperatures

Oct 17, 2012

When frost is on the pumpkin, be careful with your cable. Cable made of thermoplastic materials such as PVC may stiffen in cold weather. Informational notes in NEC Sections 310.10, 310.104 and 402.3 says “Thermoplastic insulation may stiffen at temperatures colder than -10° C (14° F), requiring that care be exercised during installation at such temperatures”. Although this is not a formal requirement, it should be headed. Installing cable when the temperature is too cold can damage the cable.

In the fall, when we have warm days and cold nights, people begin having installation problems with cable installation and jackets. If a cable reel has been outside all night when the temperature drops below critical levels, the inside of the reel can still be cold long after the air has warmed up. If an installation crew starts the cable pull under these conditions, the cable’s jacket or installation may be damaged.

What can you do? Keep the cable warm. Move the reel into a heated area for some time before the install. Because reels of cable change temperature slowly, it takes a while for heat to penetrate the layers of cable. Keep the cable in the heated area long enough to ensure that it is thoroughly warmed. Southwire recommends leaving cable reels in heated storage for 24 hours prior to installation.

For more information on low temperature installation, refer to:

Southwire Installation and Application Guide for 600V Conductors

Southwire Power Cable Installation Guide

- Dave Mercier