Kymasabe

So, I need to put a starter in my Cherokee and watching a couple YouTube videos, everyone says to remove the negative battery cable. Why? Why not the positive cable? I'd be afraid that the cable to the starter would somehow be live and would spark or short out if it touched metal, kinda freaks me out. Would disconnected positive cable instead work just as well?

5-Speed

Fun fact for the day. Most of the power travels through the ground wires, not the positive. There is a reason why you hear people always saying "check your grounds". When you disconnect the ground, you completely cut the circuit. I mean pulling the power wire off does the same thing but pulling the ground is more common. Either way will get the job done without creating any sparks.

00t444e

You can pull either one or both if you want to, it doesn't make much difference.

SteveMongr

The reason the ground terminal is disconnected and not the hot wire is to prevent accidental short circuits.
When replacing or removing battery, ground terminal always comes off first, and is reinstalled last. For the same reason.

Following info helps explain;

"Remove The Negative Cable First,
Re-connect The Negative Cable Last:
Why? Because the wrench or socket is touching the live part of the electrical connector. There is a good chance that the wrench or socket handle will accidentally touch something. The entire car is connected to the negative terminal.

If your wrench is on the positive terminal and it accidentally touches anything metal, you will short circuit the battery. The voltage isn't harmful, but the sudden unexpected sparks will startle the $hit out of you, and could even burn you. There is so much current (amperage) available that your wrench literally becomes an arc welder.

If you disconnect the negative cable first, and reconnect it last, then the car is not electrically connected to the negative battery terminal. After that you can disconnect the positive battery terminal with minimal risk, because if your wrench touches any metal parts of the car there is no complete circuit, and nothing happens. The only risk comes from touching the other (i.e. negative) battery terminal.

While connecting or disconnecting the negative cable, you don't need to worry about the wrench touching metal parts of the car, because everything is at the same electrical potential. You only need to keep the wrench from touching the positive battery terminal. That's easy."

kjc

Excellent answer SteveMongr!

EZEARL

One other caution. Never have your head directly over the battery when connecting cables. If the battery is empty or extremely low on fluid it can explode.

Kymasabe

Thank you all for your answers. Starter is done, pulled the positive cable. I understand the reasons for pulling the neg, but still wigs me out. Took me longer to drive to the parts store and back than it did to R&R the starter. 2 bolts, 2 wires, simple simple.

jordan96xj

Great answer by SteveMongr.


The starter is blessedly easy on an XJ. It was a gift from the engineers to make up for the heater core.

Turbo X_J

Electrons flow from negative to positive, without the negative there is no positive.

BlueRidgeMark

Nope. Power is exactly equal in the positive and negative. Mr. Ohm says so, as also the the law of conservation of energy, also known as the first law of thermodynamics.


Bingo.

Mr. Mongr's excellent answer is the real reason for the rule.


.

You got lucky. Removing the ground is the only correct procedure because it's the only sure procedure.

You happened to not do something that caused a problem.