77. An employer shall ensure that electrical equipment which may foreseeably be exposed to adverse or hazardous environments, including in particular—

(a) mechanical damage,

(b) the effects of weather, natural hazards, temperature or pressure,

(c) the effects of wet, dirty, dusty or corrosive conditions, and

(d) any flammable or potentially explosive atmosphere, including any mixture of air and a flammable substance in the form of gas, vapour, mist or dust,

is constructed, installed, maintained and modified or so protected as to prevent danger arising from the exposure.