160. Circuit breaker.- The employer shall ensure at a construction site of a building or other construction work that- (a) adequate numbers of differential ground fault circuit breakers are installed for every electrical distribution system and its sub-systems used at an excavation or tunnelling work and the sensivity of each of circuit breaker is adjusted in accordance with the requirement set out in accordance with the relevant national standards; (b) no semi-enclosed fuse unit is used in underground place at an excavation or tunnelling work. | 
