I’ve seen numerous videos on YouTube instructing to attach the red cable and then the black cable when jump starting a car (e.g. [1](https://www.youtube.com/watch?v=iI1o2hNy2hE), [2](https://www.youtube.com/watch?v=VdnkRQF5Cps), [3](https://www.youtube.com/watch?v=hyLwfthYjKw)).
However, to my understanding, black is for ground, and the reason for connecting ground in electrical systems is to prevent a potential voltage difference and creating a path for the excess current to flow into the ground (excuse me if I messed up “voltage” & “current”, my knowledge in that field is minimal). If that’s the case, then wouldn’t I want to ensure ground is connected first to prevent the risk of a voltage difference through the red cable?
I asked ChatGPT about the right order and it said “red then black”, then I explained my reasoning behind why I think black should go first, and then it said:
>You raise a good point. In some cases, it may actually be safer to connect the ground (black) cable first.
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>To minimize the risk of sparking or arcing, it’s generally a good idea to connect the ground (black) cable to a metal part of the engine block before connecting the positive (red) cable. This will ensure that there is a low-resistance path to ground in case there is a potential difference between the batteries.
EDIT: Same question about the recommended reverse order of disconnecting. Why first disconnect black then red? Shouldn’t I make sure ground is connected at all times during a circuit? If I disconnect ground first, then red is connected on its own, raising the risk of an excess current.
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It is easy to connect to the ground (black wire) in any location of a car engine, the metal part of the engine and the car body are directly connected to the ground. A good and simple connection for positive voltage (red wire) is often only available at the battery.
Batteries can give off hydrogen fumes so you do not what a spark there, which means it is simple to connect the black wire last in another location
You also what to avoid a direct short when you connect the wire that is a lot worse than some sparks when you connect it correctly, you can melt the wires and do a lot more damage. https://www.youtube.com/watch?v=ZfFViY1-zYw If you have connected the two cars with the black wire then all exposed metal parts are connected to the black wire.
When you connect the red wire to the battery of one car any mistake on the other car like connecting it to the wrong location or even just dropping it can result in short of the other battery of the first car. That is a very bad idea.
If you on the other and connect red first then the black wire can be connected to practically any other part except where the red wire is connected. Dropping the black wire will not result in a short. If you drop or connect the red wire incorrectly nothing will happen if you notice the mistake before the black wire is connected.
So red wire first reduces the risk of sparking in the wrong location and reduces the risk of you shorting the battery by mistake.
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