How Different Temperatures Affect Wire And Cable Performance

Temperature is a basic concept that needs to be understood. If something is too hot, it will melt or catch fire, and if something is too cold, it will freeze or break. This applies to everything from metal, to food, to clothing, to even liquids. This article will discuss why temperature is a fundamental consideration for all electrical applications, what happens to wires and cables in hot and cold environments, and the different temperature ratings of the most popular wiring materials.

How do different temperatures affect the performance of cables?

A consistent problem with extremely cold environments is power outages (power failures/outages). This usually occurs when large numbers of people are using high levels of energy. These temporary power outages usually occur on cold days, especially in communities with older homes, because the systems are older and more energy-intensive. These types of heaters require a lot of energy to heat a home compared to more developed systems. When many homes connected by the same power line begin to absorb large amounts of electricity at the same time, the power lines and associated transformers may not be able to meet the demand.

Another reason for this problem is the cold itself. Whether boiling or freezing, the internal components will be slightly less efficient than if the internal components were operating at optimal settings. Recent technological improvements may be able to operate more efficiently at extreme temperatures, but in any case, these moving electronic components need to work harder to achieve the same results as they would on a more favorable day.

Why temperature is an important consideration for electrical applications

Extreme temperatures, whether cold or hot, can adversely affect your wires and cables, resulting in brittle and inflexible products. When cables are installed in conditions for which they are not suitable, they can harden and break in freezing temperatures. To combat freezing temperatures, wire and cable with adequate low-temperature ratings are required. See the wire and cable material breakdown below.

Temperature Ratings for Electrical Materials

Conductors/Shields:

Silver plated copper = 200° C - 250° C

Nickel-plated copper = 250° C (27% nickel 450° C - 550° C)

Stainless steel = 250° C

Extruded insulation/sheathing.

Fluoropolymers (PFA, FEP, ECA, ETFE) - Fluoropolymers maintain performance over a range of temperatures; PFA can be used in temperatures from -200C to 250°C and ECA can be used in temperatures up to 300°C.

Polyester - As with fluoropolymers, polyester is not very flexible and is therefore used for primary insulation and thin sheathing. Maintains properties down to -100°C and below.

TPE - Excellent flexibility retention at low temperatures. tpe has been used successfully in temperatures down to -100°C.

Silicone Rubber-Most silicone rubber grades are acceptable in the -75°C to 150°C range, but specific grades can extend to -90°C or up to 250° C.

Tapes: Polyimide - general grades are suitable for 350°C

Teflon - 250°C

Mica pads-+600° C

Braided Glass Fiber -E-Glass to 250° C, S-Glass to 450° C

Filler/textile.

PTFE/PFA monofilament - 260° C

Glass fiber-E-glass to 260° C, S-glass to 450° C

Aramid-160° C

Industry standards: temperature ratings

Different industry safety standards that have been refined over the years have enabled highly resistant wire and cable products to be used in extremely demanding applications. Cold bend testing is one of the more common UL standards, while cold shock testing is another popular test used to determine if a cable can be marked with a lower temperature rating. CSA is slightly different, as legal standards may differ from UL, cold bend and cold shock testing. Checking each industry application is critical because each job has a different set of safety standards that must be met.

Wire and cable applications have several important considerations in order to successfully and safely complete the application. Various agencies have come up with different standards for specific geographic areas, and these standards have been refined over the years so that wire and cable applications can be completed safely and cost effectively. With new developments always imminent, CSA FT1-FT6 ratings, ROHS, UL VW-1 and CE ratings set the standard for completing wire and cable applications.