Disconnecting Car Battery


#1

Which cable should I disconnect first? I’ve always heard the negative should be first, but I would think the positive should be first than the negative. Thank You. George


#2

Disonnect the negative terminal first.

Electrically speaking, it makes absolutely no difference which terminal is disconnected first. The given advice is a safety consideration.

If you are working on the positive terminal first and your wrench touches any other metal part of the car (which is presumably grounded) you have created a short circuit. Not a good idea!

If the same accident happens when you are first tackling the negative terminal there is no problem.

The same rationale applies to connecting a battery. Connect the positive terminal first, then do the negative terminal.