betty2017
Member
What would happen if we connect the positive and negative poles together?
What would happen?
- Thread starter betty2017
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Monster5601
Platinum Member
If the device pictured doesn't have output current limiting, is not able to detect a short, and depending on its charge state, the jumper cable wires will have a very short life as will the device.
k0ua
Epic Contributor
For a really fun time connect a telephone central offices -48 volt power buss to ground before the main fusible link. Yes, large copper buss bars can and will turn white hot, melt and fall onto the floor.
EddieWalker
Epic Contributor
A friend in high school hooked up the jumper cables backwards on a car battery once and it exploded on him. I accidentally touched a wrench to both polls on a battery while taking off a cable and it melted a bit of the wrench off in about a second.
Xfaxman
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Nothing according to their Website: http://www.genstattu.com/tattu-400a-12v-12000mah-jump-starter-power-bank-battery-charger-led.html
mrmikey
Elite Member
I was under a tandem truck removing the starter, being a duma$$ or lazya$$, take you choice, I shorted the battery wire to ground, burnt my hand a bit and soiled the shorts and wrote the wrench........Mike
Gator6x4
Super Star Member
I had a friend that after starting on his second six pack touched the positive and negatives together on a truck to see what would happen. After he got out of the hospital people referred to him as one eye.
CobyRupert
Super Member
This is equivalent to touching a wrench to the frame and the positive (+) pole of the battery if the battery's negative pole is connected. (Assuming a modern (post-1960 12V) negative ground system)
We should all remember that this is why you should disconnect the negative post first when removing a battery, and connect it up last when installing a battery. That way there is no short circuit path from the + terminal to the - terminal of the battery through the frame, and you won't melt your wrench if you touch the frame when putting on or taking off the +terminal.
^It seems backwards to disconnect the "ground" before the hot (opposite doing work on your household AC circuit), but.....
fidowanttobe
Platinum Member
Positive cable "welded" a hole through a brand new header one time as we were so excited to fire the new engine for the first time no one noticed the cable resting against it.
LD1
Epic Contributor
Positive and negative are relative in a DC system. Don't matter weather positive ground or negative ground. Bottom line, you unhook the one that is connected to ALL the metal stuff around. That way when unhooking the other cable, the only potential to short out is directly to the other terminal, rather than the other terminal + all the metal in sight.
In household, guess I have never heard of a right or wrong way, cause SOP would be to work de-energized. Then it wouldn't much matter. But if one were to choose to work live, especially in the panel, I'd unhook the hot first. People get a false sense of security when it comes to neutrals, thinking that since they are "normally" grounded that they pose no danger of getting shocked. But once you unhook the neutral, it can indeed have 120v energizing it.
LD1
Epic Contributor
No.....
k0ua
Epic Contributor
Nope. But using a jump starter on any day always carries a certain amount of risk. Proper procedures will mitigate some of those risks.
EddieWalker
Epic Contributor
This was during our senior year in high school, in 1983. He had some minor acid burn on his face and one of his eyes, but nothing severe or serious. If you ever watched the TV Show "Mythbusters" he owns the cranes they used on the show and he was the operator for some of their experiments. He also owned the crane used in the latest Jurasic Park movie.
TCJatko
Platinum Member
According to Mr. Ohm: I (current) = E (voltage) / R (resistance). If R goes to zero (short), I (current) tries to reach infinity resulting in meltdown. If the device is protected, nothing should happen.
