how can you prevent this from happening? why would it happen?|||Always make sure everything is turned off before you start to do this. That includes doors closed so the interior lights are off.
Eye protection is necessary. There is acid in a battery and explosive gas present. If you generate a spark, the battery could literally explode in your face. I have seen it happen, and the person nearly lost their eyesight.
Always disconnect the negative terminal first. This is the %26quot;grounded%26quot; cable that is attached to the body of the vehicle anyway, so if you happen to touch the body with the wrench while touching the terminal, nothing will happen. If you try and remove the positive terminal first and the wrench touches the body while in contact with the terminal you create a short circuit and sparks will fly!
Always remove the negative first and connect it last. The same holds true when using booster cables. Positive first negative last when connecting and negative first positive last when removing. The only additional thing to remember is you should connect to the %26quot;dead%26quot; battery last. Hope this clarifies things!|||I%26#039;m loving the answers you got already, obviously from those who are not mechanics and have no knowledge of basic electrical circuits.
You took off the positive terminal first, which you shouldn%26#039;t do. As soon as the wrench, now charged positive, touched any metal anywhere on the car, as you said, sparks flew.
Always take off the negative battery terminal first, then when you touch metal parts you%26#039;re already grounded, no sparks, no melted wrench either.
When reinstalling the new battery, positive first, negative last.|||This was probably caused by detaching the positive terminal first and laying it down on the metal parts, thereby completing a short circuit.
Oh, and by the way, oklatom, I am a mechanic. A wrench doesn%26#039;t hold a charge, which will make it spark when you put it down. You obviously don%26#039;t know much about electricity. And who is it that%26#039;s giving everybody thumbs downs ?|||because you touch something medal with the wrench when you was doing it so dont touch any thing medal with your wrench and you wil be fine.. or you hook the wrong wire to the wrong post cant be touching the wire together or have anything touch medal when your working with the battery|||When disconnecting a battery, always remove the earth lead first ( Brown). When reconnecting, always connect the earth lead last.|||you either have something shorted or left on or plugged into cigar lighter socket.also remove negative cable first then the positive.reinstall positive first then negative to reduce this problem.|||dont let the cables touch the car
