When materials and works may be supplied and done under this Chapter for any person by the Commissioner

On the written request of any person who is required under any of the provisions of this Chapter to supply any materials or fittings or to do any work, the Commissioner may, in such person's behalf, supply the necessary materials or fittings, or cause the necessary work to be done; but he shall not do so in any case to which the provisions of sub-section (3) of section 641 or section 643 will not apply unless a deposit is first of all made by the said person of a sum which will in the opinion of the Commissioner, suffice to cover the cost of the said materials, fittings and work.