42. Electrical installations and equipment used underground or in confined space

It shall be the duty of the occupier of a worksite where any lighting, electric hand-held tools and inspection lamps and lights are used underground or in a confined space to ensure that —

the electricity supply for lighting and electric hand-held tools is provided by means of a step-down transformer having a secondary voltage not exceeding 110 volts centre point earthed; and

the electric hand-held tools and inspection lamps and lights are operated at a voltage not exceeding 55 volts between the conductor and earth.