Moisture is among the most common stress factors faced by electrical equipment. Electrical safety can be degraded by the effects of condensate, vapours, mists, fumes as well as splash and jet water which cause "shortened leakage and air gaps", i.e. increased conductivity between components conducting different voltages.
Protection against humidity
DIN VDE 0100-737 (January 2002) stipulates specific protection for equipment in terms of moisture ingress for damp and humid areas as well as outdoor installations.