When it comes to wire and cable, the impact of temperatures on a performance is critical. Along with weather, indoor or outdoor, dry or wet, exposed, put in conduit or directly buried, hot and cold temperatures are some of the most critical phenomena related to cable performance. If a wrong cable is used, extreme temperatures can have a critical impact on cable performance. 

Read this blog to understand the impact of hot and cold temperatures on wire and cable, how to minimize this impact of extreme temperatures, and the strategies for choosing the right cable and wire in regards to the temperature it will be exposed to.

How does the hot temperature affect wire and cable?

Hot temperatures often cause the cables to overheat. In particular, they increase the resistance of the cable conductors by forcing them to expand, making the flow of current through it more difficult, making the electrical cable less effective up to the point of it stopping working. This impact has a higher risk of happening in aluminum conductors of the utility wire in the overhead power lines. 

The insulation of the cable may withstand thermal damage as well. The insulation may melt and cause electrocution and fires. If the cable does not have an appropriate temperature rating, this has the risk of happening during extremely hot summers. However, the impact of overheating is also incredibly profound in industrial conditions, where the cables are exposed to extreme heat. In these cases, only the cable with a special type of insulation capable of surviving extreme heat will work.

What can be done to minimize the impact of high temperatures on wire and cable?

First of all, you should always pick cables that have an appropriate temperature rating. For industrial applications, the proper way of dealing with the effects of high temperatures is by installing high-temperature wiring with a temperature rating of 125 °C. Some patented industrial wiring can have an operational temperature as high as 500 °C. 

As for regular utility wiring, power companies use constructional innovative solutions to minimize the impact of high temperatures on utility wiring. Constant monitoring also appears to be the key to managing the effects of high heat on overhead wiring. With climate change, the issue of utility cables overheating is becoming more and more profound, so new cabling solutions are likely around the corner.

How do cold temperatures affect wire and cable?

Cold temperatures, including extremely cold temperatures in winter, have a damaging impact on cables. First, they result in cable conductors losing heat, which takes a toll on the effectiveness of their performance.

Another weak point when it comes to cabling and cold temperatures is that the cables are becoming less flexible up to the point of breaking.

It is difficult to install electrical cables during the cold weather and is generally not recommended to do so. Some types of cable insulation, such as the regular PVC, may stiffen due to the impact of cold weather.

When it comes to overhead power lines, wind sagging and ice-build-up are common issues that result in the loss of power. Just like with hot temperatures, proper and timely management by the utility companies is the best solution available.

Minimizing the Impact of Cold Temperatures on Wire and Cable

The first and most obvious solution is to pick the cable with an appropriate temperature rating. If cold winters are a common possibility in your area, take this into consideration while choosing wire and cable for outdoor use.

What are Cold Impact and Cold Bending Testing?

Cold impact and cold bending testing are generally accepted industry standards that predict the behavior of electrical cables in cold weather. Cold bending testing determines the flexibility of the electrical cable when bent in cold temperatures, while cold impact testing determines whether the cable is prone to damage at a certain temperature. There are different temperatures for cold impact and cold bending testing, with -60 °C being one of the most common. If you want the cable that will surely perform well in cold conditions, go with the one that passes cold impact and cold bending tests. 

Operating Temperatures Of Common Types Of Insulations

The operating temperature of the cable refers to the minimum and maximum temperatures in which a cable can adequately operate for an unlimited timespan. This is an important criterion when picking wire and cable for a particular application. Operating temperatures are variable and may depend on the manufacturer of a particular cable.

• PVC: -15°C to 70°C.
• PE: -65°C to +75°C 
• XLPE: -65°C to +90°C 
• Silicone rubber: -60°C to 180°C
• EPR: -50°C to +120°/150°C
• EPDM: -50°C to +120°/150°C
• CPE: –18°C to 105°C 
• PTFE: -240°C to 290°C 

Conclusion

In general, this list explains that thermoset insulations perform better in different weather conditions compared to thermoplastic insulations that are more likely to be impacted by temperatures in a negative way.

Fluoropolymer thermoset insulations, such as PTFE, have the highest temperature rating of all insulations, which makes them perfect for industrial wiring that deals with extreme temperatures. 

The differences between temperature ratings of particular insulations explain the performance of popular cables in various temperatures. For instance, THHN/THWN-2 runs the risk of stiffening at -10°C due to having a PVC insulation, whereas an XLPE-insulated XHHW-2 has -40°C as its temperature of risk.

In residential settings, going with thermoset insulations for outdoor applications appears to be the best solution. It is best not to use cables with PVC insulation outdoors in areas where the temperatures in the winter may reach below -15°C or -20°C. As for utility cables, they require constant maintenance to perform well in different weather conditions.

Aside from the temperature rating, you should look at various industry standards when selecting wire and cable for your application. These include UL Cold Temperature Ratings per Cold Bend and Cold Impact Testing and the tests that require high-heat resistance. In challenging and hot industrial conditions, the cables you choose should also be flame-retardant.

Nassau National Cable carries the cables with all types of temperature ratings at some of the best prices in the industry.