§ 4. The public service commission. 1. There shall be in the department of public service a public service commission, which shall possess the powers and duties hereinafter specified, and also all powers necessary or proper to enable it to carry out the purposes of this chapter. The commission shall consist of five members, to be appointed by the governor, by and with the advice and consent of the senate. A commissioner shall be designated as chairman of the commission by the governor to serve in such capacity at the pleasure of the governor or until his term as commissioner expires whichever first occurs. No more than three commissioners may be members of the same political party unless, pursuant to action taken under subdivision two, the number of commissioners shall exceed five, and in such event no more than four commissioners may be members of the same political party.

2. Notwithstanding subdivision one, whenever the commission shall certify to the governor that additional commissioners are needed for the proper disposition of the business before it, the governor may increase the membership of the commission to seven members by appointing two additional commissioners by and with the advice and consent of the senate. The terms of office of such additional commissioners and the filling of vacancies during such terms shall be governed by subdivision three, except that upon the expiration of the terms of such additional commissioners, no further appointments or reappointments shall be made to such additional offices, unless the commission shall first certify to the governor that the need for additional commissioners continues to exist.

3. The term of office of a commissioner shall be six years from the first day of February of the calendar year in which he shall be appointed and commissioners shall serve on a full-time basis. Upon a vacancy occuring otherwise than by expiration of term in the office of any commissioner, the governor, by and with the advice and consent of the senate, shall fill the vacancy by appointment for the unexpired term.