Why Does My EV Charger Get Hot?

Understanding the Heat: Safeguarding Your EV Charging System Amid Summer Temperatures

During the summer, I sometimes receive calls from customers who report that the connection at the EV outlet or the circuit breaker for their EV is hot to the touch.  Naturally, any time an electrical component starts to heat up it can be a cause for concern.  However, like all of your electrical components, your EV wall connector, outlet, and plug are designed with a certain tolerance to higher temperatures.

With some exceptions, the wiring and components are designed to withstand ambient temperatures (air temperatures) of up to 90 degrees Celsius, or 194 degrees Fahrenheit.  For reference, 100 degrees Celsius works out to 212 degrees Fahrenheit, which is the boiling point for water!  Your electric vehicle and the components installed for charging it are extremely rugged!  

Higher temperatures for the components in your EV charging system can be caused by the following factors without cause for concern:

1) Higher air temperatures make everyone's A/C run harder and longer, AND at the same time.  This causes something called "Voltage Drop".  This happens when the amount of current being pulled through the electrical system is approaching the higher end of the capacity for the transmission lines.  It is normal, but can contribute to heat build-up.

2) Higher ambient temperatures (the air temperature near your charging components) can cause the operating temperatures of the components to increase proportionately.  Whatever the temperature of the wire is (which is usually close to what the air temperature is) the temperature under load will be higher.  The higher the air temperature is, the higher the temperature of the equipment will get under load.  

When you should be concerned:

1) If you see or smell smoke, the EV charging components have overheated.  Switch off the circuit breaker immediately and contact an electrician.  This is not an "emergency" situation, but avoid using the charging system until it can be inspected by an electrician.

2) If you notice that the plastic at the plug is beginning to melt.  Again, switch off the circuit breaker immediately and contact an electrician.  Like before, this is not an "emergency".  Just avoid using the charging system until it can be inspected by an electrician. 

The big difference here is between higher operating temperatures as a result of higher ambient (air) temperatures, and higher operating temperatures due to an equipment failure.  The components for your electrical system can handle high air temperatures.  They are designed to be installed in a hot garage or hot attic and still function safely.  Most commonly, the cause of equipment temperatures high enough to cause a failure are caused by a loose or faulty terminal inside the plug or electrical panel.  Thankfully, this type of failure is easy and relatively inexpensive to fix, as long as it is caught before the wire insulation begins to burn.  

Feel free to contact Root Electric if you have any questions or concerns about your EV charging system.

Check our other Electric Vehicle FAQs here...


Satisfaction / Safety First Since 1986

Bill Root

About the author

During my tenure at Root Electric, I lead the transition of Root Electric from a primarily sub-contracting based business model to a prime-contracting based business model. Accomplishments have been made by developing a team based approach to researching and implementing a service-specific client management system.

My goals for the next five years are to fine tune Root Electric's brand strategy and to diversify its scope of services, while remaining true to the discipline of electrical work.