Conn. Gen. Stat. § 7-218

Any municipality owning a plant under the authority of this chapter may reconstruct or enlarge the same, but no reconstruction or enlargement, beyond the ordinary and necessary maintenance, repair or replacement thereof, except such increased appliances for the distribution of gas or electricity as may be necessary to furnish the same to new takers, shall be undertaken or made, unless by vote as provided by section 7-217 in case of the issue of bonds.