I’m trying to understand the reasoning behind grounding the negative side of a battery in vehicle electrical systems, given that the negative terminal has an abundance of electrons. In electron flow theory, electrons move from the negative terminal (where there is an excess of electrons) to the positive terminal (where there is a deficit of electrons).
If the negative terminal is the source of electrons, why do we consider it a “sink” and connect it to the chassis ground? Wouldn’t it make more sense to ground the positive side, which is where the electrons are flowing to?
Additionally, I’m interested in learning about the thought process and design principles that electrical engineers follow when making this decision. What are the safety, performance, and practical implications of grounding one terminal over the other?
In: Physics
It actually doesn’t directly matter wich side you ground. Voltages are potential**differences** and grounding defines where your zero potential is. So if you ground the positive side you simply get a negative voltage at the negative terminal instead of a positive one on the other side.
The flow direction of electrons is irrelevant for this. They always flow from high density to low density area basically.
What is important is that you’re consistent in that decision. If you ground plus in one device and minus in the other then touching both at the same time will electrocute you. So we just decided that negative side always gets grounded to avoid accidants
Latest Answers