Reply To: PU220-02A wiring › Forums › General Questions and Comments › PU220-02A wiring › Reply To: PU220-02A wiring 2019-03-16 at 11:10 #2680 MartynGuest Two of the terminal connectors should be marked with a 1 and a 2. 1 is positive, 2 is negative. The third, usually unmarked, terminal is the ground when ac is used. This can be left unconnected. This reply was modified 2 years, 6 months ago by Martyn. This reply was modified 2 years, 6 months ago by Martyn.