Why you must disconnect the negative terminal of your car battery first ?

Whenever you work on a car battery, always disconnect the negative terminal first and not the positive and when re-connecting, connect the positive first.

The reason is pretty simple: If you accidentally touch the engine-bay or any other grounded metal part of the car with the positive, nothing will happen. But if the negative terminal is still connected, and if you happen to touch any metal, it would result in disastrous consequences(which I don’t need to explain even to a high-school grader) since the battery will be conducting several hundred amperes.

2 Responses

  1. hector December 5, 2013 / 2:25 AM

    i connect a brand new battery in my citroen picasso. i plugged the negative terminal first and then the positive, i heard how the doors were unlocked and after that the car was dead, with a brand new battery. did i damage the car or just the battery got damaged?

    • Mithun John Jacob December 5, 2013 / 11:29 AM

      Since it’s a brand new battery, better check with a reputed garage or contact the battery dealer.

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