Why would disconnecting the positive cable first on car battery cause sparks?

[hutchphd]

Is my understanding correct?

No. Your finger is a bystander. The battery can supply a hundred amps through the ring and it will get very hot very fast. Not good.

 

[sevensages]

No. Your finger is a bystander. The battery can supply a hundred amps through the ring and it will get very hot very fast. Not good.

Oh. So in the scenario in which a person removing a car battery was wearing a ring and the positive post touches the ring and then the ring simultaneously touched the car body, would the electrical circuit created cause a person to lose the ring finger by burning off the finger (as opposed to electrically shocking off the finger per se)?

 

[hutchphd]

I believe the burns cause the damage. High voltages (power lines) can burn you by the current conducted through flesh but not a 12V battery.

 

[anorlunda]

If so, why would any significant amount of current go through the person's finger?

No. The risk is that current goes through the ring, the ring gets hot, perhaps melts, while still on your finger.

 

[sevensages]

I believe the burns cause the damage. High voltages (power lines) can burn you by the current conducted through flesh but not a 12V battery.

I was about to say that your post quoted above is contradictory. But anorlunda's post #54 explained how your post ain't contradictory.