The relative humidity range should be 45% to 75%. Excess humidity can compromise the insulation properties of electrical components, leading to potential short circuits or failures. A practical engineering tool for moisture control and reliability analysis. You must install a weatherproof cover and check the seal regularly. For outdoor outlets, use a gfci outdoor outlet with gfci protection. These parameters aim to create an optimal working environment for operators and ensure the longevity. If a weather report tells us that humidity is 100%, then we know the air temperature and air pressure are completely saturated with water. The temperature at which condensation forms is called dew point.