Climatic properties such as the air temperature and humidity in the environment where the electrical cubicles are installed are very important for the continuity of the system and the safety of the personnel.

The amount of water in the air is called moisture. As the air gets warmer, the amount of water vapor it can keep in it increases. Sudden decreases in air temperature cause some of the moisture in it to become water, which is called a dew point.

Condensed water disperses into small droplets on the surfaces inside the electrical panel, and this creates great risks for the switchgear materials in the electrical panels. These water droplets on the surface of the panel, insulators, breakers and other electrical equipment, causing the leakage path length to decrease to dangerous values, which may cause partial discharge and insulation errors. The way to eliminate these risks is to use a panel heater.

It has been determined that condensation is inevitable in areas where relative humidity exceeds 65%. When the ambient temperature decreases rapidly, it can no longer hold the water it holds in gaseous form in hot air, and it turns into liquid water droplets. To solve this situation, the heat created by the nominal current inside the panel while flowing through the electrical materials is not sufficient and an external heater must be used. In order for the relative humidity to still remain as a gas in the air, it is usually sufficient to increase the temperature in the enclosure by 10 °C. The design and type of the panel heater is very important to accomplish this task. In order for the air to heat up quickly enough to resist the sudden drop in temperature, heaters with an aluminum body with increased surface area and wrapped in stainless wire with a low resistance value change with temperature should be used. Aktif brand panel heaters are designed to provide these features.

According to the general acceptance that we can recommend, a heater power of 1 cm³/W will be sufficient for panel heater power selection. In this case, for example, a 100 W heater can be used for a 1 m³ panel. This value may need to be increased for geographical conditions or environments where humidity is high.

For detailed information, you can refer to article ‘Principles Of Anti-Condensation Heaters Used In Medium Voltage Switchgears‘.