Two Pole Switch Wiring Diagram. This is where the travelers are connected. Either 142 with ground wg for 15 amp circuits or.
In this diagram 2 wire cable runs between sw1 and the outlet. The two conductor cable from the ceiling box to the light switch is supposed to have the white conductor re identified with another color because it is not being used as a neutral but as a hot wire. The source is at sw1 and the hot wire is connected to one of the terminals there.
Local and provincial codes should be checked.
The common ground wire provides grounding for some electrical accessories such as. The two conductor switch wiring diagram at the top of this post is from older homes and is likely not used much anymore depending on which code book is in force in each jurisdiction. Rocker switch wiring diagram. Try to ground negative your tacho directly to negative pole of battery.