One wire alternator.

6. Install the charge wire from the alternator to the battery and make all connections.
· This is a “one wire” alternator, so the battery charge wire is the only connection required for
operation.

7· Powermaster recommends the battery charge wire be upgraded to an 8 AWG wire for the 140
amp unit and a 6 AWG wire for the 200 amp unit. Inline ammeters must also be upgraded to
handle the alternators rated power if they are to be used (Powermaster recommends that
ammeters be replaced with a voltmeter).

from powermaster instruction sheet...