My prius 2012 won’t turn on

To Reboot the Prius. The safest is to disconnect the red cable, the positive , from the positive terminal on the battery. On the negative side I was thinking in terms of removing the the chassis connection. If your careful, nothings going to happen, Rebooting is only a temporary disconnect anyway..
As far as shorting yourself out thru a ring or watch that takes a special talent. My resistance used to be 165K ohms, I=E/R = 12/ 165,000 ohms = .0001 amperes. As tiny as that is I still don’t make a practice of touching both polarities at the same time. Thru a ring or a watch, conduction doesn’t improve, it’s still 1/10 of a milliamp

Agree if you’re using a long wrench on the battery, for me, those days are gone forever. If the tool spans the distance of the terminals or adjacent chassis ground, get a shorter tool.

 

My brain cells can barely comprehend electricity, but there seems to be a lot of internet lore pointing to "disconnect negative first, and reconnect last". This being for the very widespread negative-ground system. One example:

Replacing Your Car Battery, DIY Battery Replacing | Pep Boys

I can recall too the first time I purchased a replacement 12 volt, I already had heard it, but the service guys were telling me the same mantra.

 

I agree with that, but, if either is disconnected and then covered in a plastic bag, then nothing will happen.
If I’m going to leave a cable off, I always cover it anyway. Including 110VAC.

 

Yeah I stuff loose leads into heavy leather work gloves, keeps them shielded. I hope...

 

Great idea.

 

Humans are involved, so that talent is occasionally found.

The problem happens when that human resistance is completely bridged by an all-metal circuit path, and current suddenly jumps to hundreds or thousands of amps. And it is even worse then the high current creates a minor spot-weld so that the electrical connection gains some mechanical strength, requiring some noticeable force to break loose.

The wedding ring case happened between electrical terminals at a traditional non-hybrid starter. I don't remember details of the watch band incident. Neither case was bad enough for the victims to have residual battle scars to show off.

 

Starting current can be enormous 150-300 amps and more with larger truck batteries. we are speaking of a Prius, any year, any model.
Anybody that works on a live starter is a nut case.

 

We are still speaking of general electrical safety. Even a Prius battery can put out damaging levels of current.

By the time I met him, he had matured into a well regarded mechanical engineer.

 

Glad to hear it.

 

that's one reason i have never worn a wedding ring, or any jewelry. table saw is another.

 

For 20 years while in USAF I always removed my ring, whether in the field or working the bench.

 

That explains your closet watch collection .

As long as Mrs. Bisco is ok without the ring, you’re good.

 

On the negative terminal first, @fuzzy1 has nailed it. I missed seeing the event, but I did see the nasty burn mark all the way around my father-in-law's wrist when his metal watch band and his wrench combined to complete a circuit between the frame and positive when he still had the negative connected. Musta hurt like a sununvagun.

On the ring, I'll just tell you about the time in the factory that I went to the nurse's office for an aspirin and she was patching up a guy's left ring finger. She said, "Jerry, where's your wedding band." I held up my hand to show them the tan line and said, "It's in my toolbox with my keys." She turned to the guy she was working on and said, "See?" I think I can guess what they were talking about before I came in. LOL!

 

Oh, it happens, no doubt about that. By talking about it we may save somebody.

 

Yup. Won't kill you, but it won't be the highlight of your day, either.