What Size Cable is Needed for Jump-Starting a Car?
2 Answers
For jump-starting a car, copper cables with a cross-sectional area of 10 square millimeters or more are recommended. Diesel vehicles require even thicker cables. There are two ways to indicate the thickness of the cable: one is by the cross-sectional area of the copper core, and the other is by the diameter of the copper core. If using the diameter measurement, gasoline vehicles should use an 8mm copper core cable, while diesel vehicles require a 12mm copper core cable. When purchasing, not only the thickness matters but also the length. Excessively long jumper cables can lead to power loss, making it difficult to start the vehicle. Generally, it is advisable to choose jumper cables that are 3 to 4 meters long. Additionally, it is important to select high-quality cables, as poor-quality ones may not only leak electricity but also potentially damage the car.
Last time I helped my neighbor jump-start the car, I realized the thickness of the cables really matters. For household sedans, 16 square millimeter copper core cables are the most reliable, equivalent to about AWG gauge 4, capable of handling 400 amps. Don’t just use leftover thin wires from home renovations—I once saw someone use a wire as thin as a phone charger cable, and it started smoking immediately. The red and black cables need thick enough insulation to be durable; just check the numbers printed on the cable—look for 16mm². For temporary emergencies, 10 square millimeter cables can work, but if the wires get hot during ignition, remove them immediately. Also, a reminder: trucks need at least 25 square millimeter cables, especially diesel vehicles, which demand more current.
