loowiloowi
Junior Member
I thought that all driver Model A's had a battery disconnect on the ground side....
6v Alternator
- Thread starter DBSHELTON
- Start date
Does that really matter? Mine are on the Minus side.
BRENT in 10-uh-C
Well-known member
Ground side and Minus side can be two totally different items.
In a nutshell, interrupting the ground circuit to the battery does nothing if the circuit is re-connected by a battery that rubs against a grounded object, -or has a brake rod/etc. become the new ground. On the other hand, when the power source is disrupted through a switch, it does not matter if something shorts out the ground circuit.
I am now confused. So, on a positive ground system, would you install the disconnect switch on the + battery terminal cable or the - battery terminal cable.
BRENT in 10-uh-C
Well-known member
Ummmm, ...that really is not the way it is supposed to be done. The interruption needs to be between the battery and the main power line feeding all of the circuits power. In the case of the Model-A, this is the wire feeding the starter switch which has the chassis wiring harness attached.
Whether the Model-A is wired positive or negative ground in this instance is moot.
BRENT in 10-uh-C
Well-known member
Lets break this down further. Pretend you remove the "+" and the "-" labels from the battery. At this point, it really does not matter whether it is considered a + ground or - ground when you connect the battery cables, -especially if the battery's current has been drained.
So if the disconnect switch is placed in the cable between the battery post and the chassis ground, even with the switch turned off, I can potentially lay a screwdriver (-or any piece of metal) on top of the battery and over to any component (frame, transmission, brake rod, etc.) and re-connect the ground to the system. Therefore having the disconnect in the ground cable is useless. Now if the disconnect switch is placed in the battery cable connecting the starter switch to the battery post, any short that happens on the opposite side of the switch (opposite side of battery post) can have the power disrupted and stop any short from creating a fire.
Does this help you understand??
Either way interrupts the current path. With the switch open, the only way you get a short is directly across the battery posts. Placed on the hot side the switch exposes more bare metal to the post area. On ground side no worries using a metal tool or extension to operate it.