Me. Rev. Stat. tit. 35-A, § 712

Any contract in excess of $2,000 between a public utility and a contractor for the construction of facilities located on private property for the exclusive use of a private individual and for which the private individual is required to pay the total cost directly to the utility, shall be awarded by a system of competitive bidding. Unless there are valid reasons to the contrary, contracts shall be awarded to the lowest responsible bidder.