Can This Be Done?

Dr. Walt · Jun 29, 2014

Didn't want to steal the thread on the "Negative Ground" post.

Can a vehicle electrical system be run as a totally isolated system; NOT using the frame, engine block, sheet metal or any other metallic part of the vehicle as an electrical conductor ?

Yeh, yeh, I know, somebody has always got to come along and confuse the issue - BUT, I'M CURIOUS, can such a thing actually be done, and WORK?

Personally, I don't think it's possible - but I DON"T KNOW for certain.

THANKS in advance for any & all answers.

Doc :>)

Anonymous-0 · Jun 29, 2014

Think of a fiberglass bass boat.

There's your answer.

OldFarmTractor · Jun 29, 2014

How would you connect the starter to the system? Most starters only have one pole, using the frame for the other pole.

Frank 41 · Jun 29, 2014

Doesn't there have to be s ground some where?

snoopnc · Jun 29, 2014

I'm thinking what you are asking is theoretically possible, but require one *&&^ of a lot of wiring. everything would have to be eventually wired back to the negative terminal of battery. I believe (in theory) you could make a wooden framed vehicle and wire it for electricity, but everything electrical has a positive wire AND a negative wire.

Just had another thought...trailer wiring whereby the "ground wire" is run through the plug and "grounding" is accomplished through the wiring in addition to frame contact through the hitch.

That's MY OPINION ONLY and...as I've heard here before..."Your mileage may vary".... LOL!!

Rick

notjustair · Jun 29, 2014

I'd say it could be done with twice as much wiring. You would have a ground running to everything, too. With as much plastic as there is in a car now many of the looms have grounds running in them to the various lights and things (think turn signals on a plastic bumper). It would kind of mirror household wiring - several wires where there may only be one running to a light.

waltdavies · Jun 29, 2014

It's grounded to the engine.
Walt

john *.?-!.* cub owner · Jun 29, 2014

It could be done, but is not practical. The starter, generator, and distributor all ground through their own housings back to the tractor chassis.

big jt · Jun 29, 2014

It can be done.

A retrofit isn't real practical though. Needs to be done from the ground up. Most components in the industry are built for a frame ground. Those would need to be made for a separate wire ground instead of grounding through the mount.

jt

Greg1959 · Jun 29, 2014

oldfarmtractor- You would run a ground from the bolt that bolts the starter housing to its support. i.e. wood, fiberglass plastic, etc. to the ground from the batter/fuse block.

FLOLDFORD · Jun 29, 2014

Your right about the fiberglass boat. I do rewiring work on boats to make a little extra money to support my old tractor hobby. Boats have to have multiple ground circuits because of the hull being non conductive. Even aluminum hulls don't use the hull as a ground ( can you say really bad electrolysis ) One thing I've learned when trouble shooting a wring problem on a boat is to have two test lights one with a short lead to go to the ground circuit I'm working on and one with a really long lead to go all the way back to the battery. I never use the boat motor as a grounding circuit other than the starter because of to many problems with corrosion especially around salt water. So like the others have said yes it is possible. Just going to take a lot more wire

Dr. Walt · Jun 29, 2014

THANKS EVERYONE !

I was thinking more along the lines of a car, truck, or tractor, but as "Buzzman 72" pointed out - a fiberglass boat - WOULD have to have a totally isolated electrical system.

:>)

Bob Bancroft · Jun 29, 2014

Sure. As said below- think boat.
My airplane has a heavy ground cable running right to the starter, along with the power cable. The engine is mounted on rubber isolators. It's not a totally isolated system like a fiber glass boat would have to be, but partially, at least.

One of my tractors has little brown ground wires running all over the place. Again, not a totally isolated system, but it approaches what you're talking about.

60 acre hillside · Jun 29, 2014

My old Mercedes Benz had some circuits with a separate negative wire although the whole chassis was negative. This car had few electrical problems

jm. · Jun 29, 2014

I have never seen a distributor that did not get its ground from the engine mount so when you say not using the engine block , you would have to isolate the distributor mount but again anything is possible.

David G · Jun 29, 2014

The 24V John Deere"s were pretty close to that.

ih_bug · Jun 29, 2014

I would like to see how you would do the spark plugs ?

Geo-TH,In · Jun 29, 2014

When it comes to lawn mowers with plastic hoods and fenders, they run a ground wire. I think the tail lights on my truck have a ground wire too.

If you didn't grouond the engine, you would have to run a very large ground wire for the starter and come up with a way to make a spark without grounding.

My 62 XKE had a positive ground. Some thought that a positive ground help prevent rust. Rust is formed by iron loosing 2 electrons. Don't really think it helped cars, however preventing the loss of electrons with an anode in water heaters works.
George

MarkB_MI · Jun 29, 2014

It is common for aircraft to run both power and return conductors to every device, usually through a "twisted shielded pair", which is, as the name implies, two conductors twisted together and covered by a grounded shield. This is done to improve electromagnetic compatibility. When current through a twisted pair is turned on or off, it won't generate noise like a single conductor will. Likewise, twisted pairs pick up less noise from other sources than single conductors. Typically, all the returns are connected to ground at a single point to eliminate current through the fuselage.

Indiana Ken · Jun 29, 2014

The frame etc. is simply another connector to complete the circuit. If you choose not to use the frame, there is no frame or the frame is not conductive an actual wire can be used to complete the circuit.

In the case of spark plugs; typically spark plugs require the engine block to be conductive. However, I don't see why a dual electrode plug could not be constructed. In the case of a diesel engine this is not an issue.

Using conductive structural members for one leg of the circuit has saved a lot of copper over the years.

Can This Be Done?

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