Jumper cables are a more common name for a jump-start vehicle battery cable. These have heavy gauge (often four or six gauge wire) clamps on either end that are color-coded positive and negative with red and black. These cables are typically only used for as long as it takes to charge a dead car battery, allowing the other two batteries to start the vehicle without the dead battery. Usually, this lasts no more than 15 minutes. Jumper wires can be left connected for longer in an emergency when a charger is not accessible, such as when the alternator in the automobile with the dead battery is questionable.