Hot EV charging Cable

Some of you may have heard of the crime taking place with the theft of EV charging cables. Thieves have been cutting the cables and selling them for scrap copper. But let’s not confuse HOT with stollen EV charging cables. Heat generation is a normal part of the EV charging process, understanding why and how, is something few know about.

Several factors can affect how much heat your EV charger generates. These include the charger’s design, the ambient temperature, and the duration of charging. For instance, charging on hot days can lead to higher charger temperatures, as the ambient temperature adds to the heat produced by the charger. Prolonged charging sessions also contribute to increased heat buildup.

Hot EV charger cables are normal. However, the cable should not be so hot that you can’t touch it.

The amount of power your car battery receives is substantial and having the cable warm up is a normal thing. As electricity travels through the cable to the battery every component from the Breaker to the charger, to the cable, to the charge plug, to the battery, get hot. The resistance of a cable is based on how long, thick, and what material it is made of. Doubling the length of a cable doubles the resistance. Increasing the thickness decreases it. Both the car and the charger manage their separate hardware to ensure safe charging.

Technically, wire heat is the square of amps. For example, a #8 SER is rated 50A nominal 40A continuous at 75C thermal. That rating is based on 30C ambient temperature, so the balance of 45C is to cover the heat from charging. EV chargers come with cables that under normal operation can handle the heat. They are designed for it. Sometimes things can go wrong.

Excessive heat could be a sign of a cable failure, or imminent failure, due to cable damage, a damaged charge connector, crimped or lose wire, dirt and more. Proper inspection of the cable is recommended. The charge cable will get "very warm" at the vehicle connector side and the cable will be quite warm to the touch as well. However, if it feels like you are going to scald yourself and get that instinctive reaction to let go or get burned, then its recommend that you call for service. If necessary, a replacement cable may be required. We have prepared an inspection guide, request one from info@hwisel.com   

If it turns out that you don’t have a problem, it is still advisable to perform regular inspections and maintenance to sure safe EV charger usage.

Hwisel Technical Team