Installation of a two pole on off master switch

[old31]

I am getting ready to install master cut off switch.

Not sure, does one cable go to the negative battery and the other cable goes to the starter?

This is a 6 V positive ground.

[SDJason]

When I put one in, I installed on the Ground side

[Russ B]

There are advocates for cutting the power either way. I always put my switch between the battery and ignition switch/starter.

[Synchro909]

I find the best place for it is between the chassis and the earth side of the battery. +ve if 6 volts, -ve if 12 volts. I mount the switch either under the floor so I reach it with a finger through a hole in the floor board or in the seat riser. Both are easily accessible from the driver's seat and leave NO chance of anything being hot when it is turned off.

[Oldgearz]

I have mine hooked up the way you say (neg. battery to one pole switch, other pole to starter. My switch is on the firewall near the clutch (inside the cab). It cannot be got at from the seat, but it is out of the way and not very visible. I pen the door, bend forward and turn the switch, then hop (I'm 77 so as the "Young Frankenstein movie says, "nice hopping") into the seat. Works for me and I have no need to put it anywhere else.

[Keith True]

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I have never seen one good reason for putting the switch on the hot side of the battery.I saw two minor catastrophies in A's from doing it that way,one on a JD crawler,and one on a Ford Maverick drag car.On one A the switch was mounted on the firewall,and the hot cable pulled out of the eye and dropped down bouncing over everything.Another had it in a lollipop mounted to the starter,that cracked and shorted on everything it hit.The Maverick had a toolbox slide into it,and it just blew a hole in the toolbox.

[GPierce]

In series on the ground cable.

[David R.]

It is actually a single pole switch. Single pole, single throw, (two terminals). Sorry, the electrician in me coming out.

[VT Cruzan]

I have installed a number of these cut out switches on a bracket attached to the left side of the steering column. Always on the ground side between the positive battery post and a good ground. It is an easy location to reach and quickly becomes a step in the starting and shutting down routine.

[PC/SR]

#7 Shut off the ground side. Otherwise everything up to the switch is still hot. Shut off the ground and nothing flows.

[TomInCologne]

My 'Margarethe' has a shut-off switch mounted to the firewall on the negative side of the battery between battery and starter. the connections are not insulated. handling a spanner in the engine compartment, even for the slightest adjustment, you always run into the danger of contacting the hot terminal and welding the spanner to engine/switch/car.


I will change this to between positive terminal and chassis.

[Bob Bidonde]

My cars have a battery disconnect switch cut into the lead to the starter switch.

[Patrick L.]

I prefer to mount them where they are easily accessible. In other words inside the cab along the seat riser.

Its easier to mount it in the starter lead, especially if 2 ground leads are being used. Many folks add an extra ground lead to the bell/ trans.

It may be better to mount in the ground lead, but, either way will work fine. Its better just to have one thats accessible than not to have one if its ever needed.

JMO, which is worth what you paid for.

[Big hammer]

I just leave the ground/ earth battery terminal a little loose ( Tom Wesenberg’s way), lift the mat pop the battery cover and wiggle the terminal off ! Having an inline fuse for the electric’s the only reason to remove the terminal other than maintenance or not in use time, would be if the starter switch sticks. 50 years ago when my A was new to me, I was at a car wash cleaning the engine preparation to detail the engine, smoke started coming out off some wires and I quickly removed the ground battery terminal ! Note to self leave the ground terminal a little loose !!!!

[Oldgearz]

You're going to have a hot lead to the starter no-matter how you hook up a cutoff switch. I find confusion over why a cutoff switch cable can come loose but somehow the starter cable does not provide the same risk. I have a second ground cable (pos) to the transmission from the battery, so I use the neg cable to the cutoff. Works for me.

[katy]

Originally Posted by David R.

It is actually a single pole switch. Single pole, single throw, (two terminals). Sorry, the electrician in me coming out.

Single pole, single throw, = on or off.

[old31]

Interesting thread. Appears to be a 50/50 mix about the cable locations.

I have a roadster and I am mounting the switch on the riser a little right of my right leg, just about in the middle of the seat with 1/0 AWG battery cables for Amazon.

So, unless someone says STOP, I will go with one cable to ground and the other to the top of the starter.

[gdmn852]

Mine Roadster has one installed on the seat riser , easy to get at , it also cuts ground, if on the hot lead the wire can short out if it contacts ground, anything metal on the car.Many car repair manuals recommended disconnecting the battery ground when working on them.

[SDJason]

Originally Posted by old31

...I will go with one cable to ground and the other to the top of the starter.

For standard wiring, isn't the Starter hooked up directly to the negative terminal of the battery, and the positive terminal of the battery goes straight to ground (i.e. the car frame)?

Edit - I assume you are describing the new cables you plan to connect to the master switch you plan to add. I think you need to clarify where you plan to add the wiring for the switch.

If you hook the top of the starter to ground (via the added switch), where do you plan to connect the negative terminal of your battery?

[Patrick L.]

Originally Posted by old31

Interesting thread. Appears to be a 50/50 mix about the cable locations.

I have a roadster and I am mounting the switch on the riser a little right of my right leg, just about in the middle of the seat with 1/0 AWG battery cables for Amazon.

So, unless someone says STOP, I will go with one cable to ground and the other to the top of the starter.

The last sentence can be confusing, at least too me. The switch is mounted in series in one wire.