Maximum electrical cable temperature: regulatory values, materials, and current-carrying capacity tables
The selection and sizing of electrical cables is not based only on the current to be carried, but also on the maximum temperature the cable can withstand without compromising the safety or performance of the system. The maximum temperature of electrical cables is a crucial parameter to prevent overheating, premature aging of the insulation, and, in the most serious cases, short circuits.
In this article we will analyze regulatory values, material behavior, current-carrying capacity tables, and selection criteria for correctly choosing cables based on temperature.
The maximum temperature of an electrical cable is the value beyond which the insulation and conductive materials begin to deteriorate irreversibly. This limit varies depending on the type of insulating material used:
| Insulation type | Maximum operating temperature |
|---|---|
| PVC | 90°C and 105°C |
| Silicone | 180°C |
| PTFE (Teflon) | 250°C |
| Glass fiber | 450°C |
| Special glass fiber | 700°C |
Exceeding these limits can lead to loss of insulation, short circuits, or fire hazards. The CEI standards take these values into account to define test conditions and operating limits.
The maximum temperature reached by a cable depends on several factors:
The current-carrying capacity tables (CEI-UNEL) indicate the maximum allowable current for cables depending on operating temperature and installation conditions.
| Nominal cross-section [mm²] | Current capacity in air [A] | Max temperature [°C] |
|---|---|---|
| 1.5 | 25 | 90 |
| 2.5 | 33 | 90 |
| 4 | 46 | 90 |
| 6 | 60 | 90 |
Each material used in cables has a thermal limit beyond which chemical and mechanical degradation occurs. Below is a comparison of the most common materials:
| Insulation material | Main advantages | Thermal limits |
|---|---|---|
| PVC | Economical, good dielectric properties | Becomes rigid above 70°C |
| Silicone | Excellent heat resistance and flexibility | Excellent up to 180°C |
| PTFE (Teflon) | Excellent dielectric properties | Resists up to 250°C |
| Glass fiber | High thermal stability, flame resistant | Resists up to 450°C |
| Special glass fiber | Extreme high-temperature resistance | Resists up to 700°C |
The main standards governing the selection and use of electrical cables based on maximum operating temperature are:
Correct application of these standards is essential to ensure system safety.
For a correct cable selection based on maximum temperature, follow these steps:
The maximum temperature of electrical cables is a fundamental parameter for designing safe and reliable installations. Knowing material limits, correctly interpreting regulatory tables, and assessing environmental conditions allows you to always choose the most suitable cable.
Caviterm supports industry professionals with high-temperature cables for every need, up-to-date tables, and custom solutions.
Contact us for more information.
