11 Mar 2026
In many electrical projects, when a cable feels hot or experiences overheating, the first conclusion that often appears is:
“The cable quality must be poor.”
However, in many technical investigations in the field, the real cause is often not the cable itself.
Cable overheating is more frequently influenced by installation conditions, operating environment, and electrical load usage patterns.
If the operating temperature remains too high over a long period, the consequences can be serious:
accelerated insulation degradation
reduced reliability of the electrical system
increased risk of power system disturbances
Below are some of the most common causes of cable overheating found in field installations.
When many cables are installed too closely together in a cable tray or duct, the cable’s ability to dissipate heat decreases.
As a result, the cable temperature may rise even though the electrical current is still within the nominal cable rating.
In power system design, this condition is usually compensated by applying a derating factor.
However, in real installation practices, this factor is often not optimally considered.
Most cable capacity calculations assume an ambient temperature of around 30°C.
In reality, field conditions are often much higher, for example in:
enclosed panel rooms
building basements
utility tunnels
industrial areas with elevated temperatures
Such environments can significantly increase the cable’s operating temperature.
In many electrical systems, additional loads are introduced after the system has already been in operation.
If the cable capacity is not reevaluated, continuous overload can increase the conductor temperature and accelerate insulation aging.
Interestingly, in many cable system failures, the hotspot actually occurs at the joint, not along the cable itself.
This is usually caused by:
improper crimping
incorrect lug size
inadequate insulation preparation
A joint with high resistance can generate localized heating, which is often misinterpreted as overheating of the cable itself.
???? Key Takeaway
In practice, cable overheating is rarely caused by a single factor.
It is usually the result of a combination of:
electrical system design
cable installation method
operating environmental conditions
electrical load usage patterns
Understanding these factors from the design stage through installation can help prevent many potential electrical system failures.
???? Question for engineers
Based on your experience in electrical projects, what is the most common cause of cable overheating you encounter in the field?
A. Cable grouping in cable trays
B. System overload
C. Termination / joint issues
D. High ambient temperature
