Problem fusing my grounds

[helotaxi 5,000+ posts]

If the ground shorts to the body, since the body is grounded there is 0 difference in potential thus no current flow and no need for a fuse. Nice try though.

Exactly, so why in the hell would you fuse it? The fuse is there to protect the wire from a short. A short on the ground side is inconsequential. If the wire is correctly sized the amp will never draw enough current to be a fire hazard on the positive or negative.

I see what you're getting at but why buck convention? If you fuse the positive battery wire, the negative is totally redundant. If you only fuse the negative you're simply going against convention for the sake of being different. You don't gain any added benefit.

 

[n2caraudio 10+ year member]

It's not my advice. I am not fusing my grounds as the troll OP suggests. I just wanted to jump in here and prove with fact and logic that you guys don't know what you're talking about... because you just simply do not. I'm shocked at the KHA revelation. I always thought you were respectable.

You have certainly proven something.

 

[helotaxi 5,000+ posts]

You suggest that only fusing the ground wire provides protection? really?

Depends on where the fuse is placed. If the fuse isolates the battery from the rest of the circuit and every ground strap from the engine is fused as well, then fuses on the negative wire would provide short circuit protection. It would be a silly way to go about it and would cost you every circuit in the car as already mentioned, but it would still work.

when the entire car metal is a ground plane, where do you fuse that circuit to provide over current and short circuit protection? you can't fuse once at the battery ground because of the fuse size. fusing at the ground connection is pointless since the positive wire isn't protected and subject to damage. we fuse positive wires at the source because of the ground plane. polarity doesn't matter - the car metal could be 12V and all wires ground wires and we'd fuse ground wires then.

The car chassis is only a ground plane when it is connected to the battery negative terminal Sever that connection and the chassis is irrelevant.

Fusing the battery negative would in theory provide protection. In practice it would be effectively impossible to implement as the sole means of protection for all the car wiring since the fuse would have to fulfill the mutually exclusive goals of being small enough to protect the smallest wire while large enough to allow all circuits to operate correctly. It would also leave you subject to being wholly screwed if you manage to blow the fuse and don't have a spare handy.

 

[keep_hope_alive Premium Member]

i contest that just fusing a ground IN A FAWKING CAR is not providing protection. i've already stated that in a simple series circuit it doesn't matter. but we're not in a lab, we are in the real world dealing with real cars. why on earth are you trying to argue with me? get your head out of Circuits I text books and apply your knowledge on something tangible.

a car has hundreds of ground points and the entire vehicle is the ground plane - that is why it matters.

a modern car is filled with computers and electronics with switching circuits - those cause noise on grounds and if ground potential (caused by current + resistance) is too high. minimize ground resistance, minimize ground potential, minimize noise.

there is a lot i could teach you, if only you'd STFU and listen.

 

[BlactimusCrime 10+ year member]

One fuse on the negative side at the battery will not protect bc of the required fuse size (wires would melt before it blew)... if you individually fuse each circuit after the load (negative side) then it will work and there would be no difference between that and fusing normally, suggesting no wire previous to the fuse came undone and grounded out.

 

[chillin 10+ year member]

Is the OP a member with a different name? Maybe someone previously banned?

 

[n2caraudio 10+ year member]

i contest that just fusing a ground IN A FAWKING CAR is not providing protection. i've already stated that in a simple series circuit it doesn't matter. but we're not in a lab, we are in the real world dealing with real cars. why on earth are you trying to argue with me? get your head out of Circuits I text books and apply your knowledge on something tangible.
a car has hundreds of ground points and the entire vehicle is the ground plane - that is why it matters.

a modern car is filled with computers and electronics with switching circuits - those cause noise on grounds and if ground potential (caused by current + resistance) is too high. minimize ground resistance, minimize ground potential, minimize noise.

there is a lot i could teach you, if only you'd STFU and listen.

Ego's are too high to listen and reading comprehension is too low. LOL

 

[PIITB Wut Wut 10+ year member]

thread haz lulz

 

[helotaxi 5,000+ posts]

a car has hundreds of ground points and the entire vehicle is the ground plane - that is why it matters.

This premise is fundamental to the validity of your argument and, unfortunately, since it is FALSE your argument is invalid. The battery negative terminal (with the car off) and the case of the alternator (with the car running) are the points of zero potential. The chassis is merely a buss bar connecting all other negatives back to true ground. If you cannot grasp this then you are beyond help. If you don't believe me, disconnect the battery negative and see how well anything in the car works. Conversely, you could connect everything back to the battery completely eliminating the chassis from the equation and it would all work just fine but it would waste a lot of wire.

I agree that in practice, fusing the battery negative as the only protection cannot work but that isn't what you're arguing.

 

[helotaxi 5,000+ posts]

One fuse on the negative side at the battery will not protect bc of the required fuse size (wires would melt before it blew)... if you individually fuse each circuit after the load (negative side) then it will work and there would be no difference between that and fusing normally, suggesting no wire previous to the fuse came undone and grounded out.

Actually fusing every circuit between the component negative terminal and a chassis ground might provide protection against a component overcurrent condition but it would not provide any protection against a short circuit as long as the chassis is still connected to the battery negative. There would still be potential between the positive and the chassis and with no fuse on the positive, this could still allow a short and a fire.

 

[MONSONwarrior Premium Member]

this thread kinda makes me wanna ditch my Kinesiology major and go for electrical engineering

 

[n2caraudio 10+ year member]

this thread kinda makes me wanna ditch my Kinesiology major and go for electrical engineering

You wouldnt need to. Fifteen minutes of basic electronics would bring you up to speed. This isnt rocket science, most of the arguments here are merely misunderstanding what they are reading.

 

[helotaxi 5,000+ posts]

High school physics tells you all you need to know...

 

[MONSONwarrior Premium Member]

You wouldnt need to. Fifteen minutes of basic electronics would bring you up to speed. This isnt rocket science, most of the arguments here are merely misunderstanding what they are reading.

Oh I'm not saying to understand this. I completely understand it, I'm just saying it's more interesting than body movements.

 

[n2caraudio 10+ year member]

Oh I'm not saying to understand this. I completely understand it, I'm just saying it's more interesting than body movements.

Roger that! This thread is more fun then midget tossing and elephant rides.