Jumper Cables in cars

Jumper cables in cars are used in cars to start a car whose battery is dead.  Car batteries can get drained due to a variety of reasons such as forgetting to switch of a light, Keeping the car unused for  long periods of time, ageing of battery, etc.  

Jumper cables are used to start the engine of a car by using the battery of another car.  Once started, the car's alternator will charge the dead battery.  The jumper cables is made of copper.  It is thick with special heavy duty clamps which can withstand currents of nearly 500 amperes.  

The positive of the live battery is connected to the positive of the dead battery.  The negative of the good battery should be connected to any metal bracket or any other metallic part of  the car to be jump started.  (Do not connected the negative of the good battery to the negative of the dead battery as this may result in sparks or a battery explosion.)

Keep both cars in neutral gear.  Start the good car and let it run for a few minutes.   Now start the car with the dead battery.  

The ignition key is turned and the starter motor runs with the power from the live battery.  Once the engine is started and runs for a few minutes, disconnect the cables in the reverse sequence.  The car with the dead battery should be kept running for at least 30 minutess to charge the dead battery.