155. Emergency generators.- The employer shall ensure at a construction site of a building or other construction work that- (a) every compressed air system in a tunnel is provided with emergency power supply system for maintaining continued supply of compressed air in such compressed air system and is capable of operating air compressor and ancilliary systems of such compressed air system. (b) the emergency power supply system is maintained and is readily available at all times at an excavation or tunnelling work. | 
