North Carolina EMT State Practice Exam

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Prepare for the North Carolina EMT State Exam with interactive quizzes and comprehensive explanations. Master your skills and gain confidence by reviewing key topics before test day!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

Which line should be disconnected first when working with a car battery?

Positive line
Negative line
Both lines at the same time
None; it is unsafe to disconnect

The correct answer is: Negative line

When disconnecting a car battery, the first line to be disconnected should be the negative line. This practice is crucial for safety and helps prevent short circuits. By removing the negative connection first, you eliminate the risk of accidental electrical discharge that could occur if a tool or object inadvertently touches the car's metal body or the positive terminal afterward. If the positive terminal were to be disconnected first, any contact of a tool with the vehicle's metal ground while still connected to the positive terminal could create a dangerous short. Disconnecting the negative first ensures that the circuit is safely broken. In addition, if the negative cable is removed and there is a fault or accidental contact made while working on the battery, the risk of sparking and potential injury is considerably reduced. Therefore, the recommended safety procedure is to always disconnect the negative line first before handling the positive terminal.