What does this mean?what you are seeing is a grounding through the points
Normal wiring is to wire the "P" lead to the switch and the shield from the ground post on the mag to the other side of the switch. The switch connects the "P" lead to ground through the shield. Some people use airframe ground to ground the mag, although it is not recommended.Ah, ok. And this grounding is done through the keyswitch when the switch is in the OFF position? This requires that there be a wire from the switch to the GND terminal on the switch, no? From reading through old threads on ignition wiring it seems some people leave that wire off... wouldn't that leave a mag always hot (if the keyswitch had no physical connection to ground)?
The points open and close as the mag is turned. When the points are closed, you will see a "ground". At some point you will not see this ground. To make the mag "OFF", the "P" lead post must be grounded externally.
Phil,
When you have your P-lead wire correctly made up, you will have two ring terminals on each end (total of 4 on each P-lead) There will be a terminal on the wire, and one on the shielding of the wire.
On the engine side, the wire will be connected to the stud on the mag, and the shielding will be connected to the ground screw (assuming that you have Slick mags). The other end of the wire will go to either the left or right (look for the L or R) on the back of your switch. The GND terminal on the switch is to ground the switch for correct ignition operation. This is NOT the place to ground the shielding.
As Mel stated, most folks find an airframe ground for the shielding that is near the switch.
Normal wiring is to wire the "P" lead to the switch and the shield from the ground post on the mag to the other side of the switch. The switch connects the "P" lead to ground through the shield. Some people use airframe ground to ground the mag, although it is not recommended.
The GND terminal on the switch is to ground the switch for correct ignition operation. This is NOT the place to ground the shielding.
As Mel stated, most folks find an airframe ground for the shielding that is near the switch.
If I have interpreted the instructions correctly:
ACS switch instructions have you grounding the center ground lug (#5) on the switch to the airframe locally, with no P-lead shields connected at the switch end.
AeroElectric instructs to connect the P-lead shields to the ground lug (#5) and no local grounding.
Which is correct? Perhaps both? Advantages of either over the other?