How to Prevent Condensation in Electrical Cabinets

Why moisture forms inside switchgear and how inspection teams can reduce the risk.

Condensation appears when a surface falls below the dew point of the surrounding air. A cabinet can be dry during the day and wet overnight if temperature changes are large and ventilation is not controlled.

Find the temperature cycle

Record cabinet temperature, ambient temperature and humidity at different times. Door opening, outdoor walls, cold metal frames and shutdown periods can create a repeatable cycle.

Control the cabinet climate

Depending on the enclosure and design, a heater, thermostat, fan or humidity controller can keep surfaces above the dew point. Select equipment according to the cabinet volume, ingress protection and local electrical requirements.

Inspect seals and cable entries

Damaged gaskets, open cable glands and unused holes allow humid air and dust to enter. Repair the enclosure before increasing heater power; a climate device cannot compensate for a badly sealed cabinet.

Document the result

After a corrective action, record the same measurements for several days. Look for dry surfaces, stable humidity and no new corrosion on terminals.