Electrical question-54 Mercury

[Bob from Northport]

For vehicles that have a 6 volt pos ground system, are any fuses in the vehicles electrical system fused on the positive ground side wiring or on the negative side?? I'm thinking on the neg side.

[Abe Lugo]

I don't think fuses care as long as you don't short them out.

The only thing I can think of is LED that have polarity. Even then they are making them go either way.

We got a 33 Plymouth 6 volt POS ground with updated signals that have fuses but the wiring it set up for pos ground. If you were to ground the - side to the body someplace the fuse will pop.

[miker98038]

I’ve never really thought about that. But I’m guessing the fuses are on the negative side. Like the lights, the switch is fed with the “hot” lead, in this case negative. It protects the wires leaving the switch, more or less, and the wire feeding the switch in case of an overload. Things like the clock and radio are grounded to the positive side when bolted in, so there’s no convenient way to fuse the ground or positive side.

It’s the way it was done in the day, but there’s some wires in my 55 bird that went quite a ways before there was a fuse. Poor engineering. But the alternative in those days was a fusible link at the hot connection. Not ideal by today’s standards either.

[poolplayer1]

Being that the source (Power) is on the negative side, any fuse would be inline with the negative side . Positive side of course is grounded to body or frame or both.

[dmsfrr]

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Originally Posted by Bob from Northport

For vehicles that have a 6 volt pos ground system, are any fuses in the vehicles electrical system fused on the positive ground side wiring or on the negative side?? I'm thinking on the neg side.

Originally Posted by poolplayer1

Being that the source (Power) is on the negative side, any fuse would be inline with the negative side . Positive side of course is grounded to body or frame or both.

An electrically powered item is grounded to the body, frame or engine where it is attached or mounted to the body, frame or engine. I'm betting it would be very impractical to have the powered items attached with some sort of insulating device so a fuse or circuit breaker could be added for that connection.

Additionally, when Ground circuits are interrupted or in poor condition electrical items on the vehicle will misbehave... so not practical from that standpoint.
Examples: a vehicle with 4 headlamps... when turned on one will appear normal and the other three will be much dimmer. Or... tail lights that turn off or appear to switch sides when you step on the brake pedal or use the turn signals.