Quote Originally Posted by freonjoe View Post
I was taught to disconnect the negative first too. This is from cartalk:

It was already said but I'd give you a more detailed explanation. If you
touch positive to negative battery post with a piece of metal it will create
a circuit (a short--dangerous). As you know the negative cable on the
battery is connected to the metal part of your car (body). If you touch the
positive post of the battery to a metal section on the car it will be the
same as touching the positive terminal of the battery to the negative which
will create a short. If you remove the negative cable first, now the metal
part of the car is not connected to the battery in any way, so even if you
touch any part of the car's body while you're messing with the positive
post, it won't short out and do nasty things (best case you'll get some
sparks and that would be it). If you're removing the positive cable first
and the negative cable hasn't been disconnected from the car body, and you
touch the metal of the car with your wrench while you're unscrewing the
positive connector, you might get shocked if there's no isolation on the
wrench. That's why people recommend removing the negative terminal first.
Now if you don't touch any part of the body with your wrench while you're
touching the positive terminal, you have nothing to worry about.

Hope this helps.



--Viktor
i like that answer the best, its a lot less confusing than reading all those articles