Mechanic Glossary

Jumper Cables

A pair of heavy-gauge, insulated electrical wires with spring-loaded jaw clamps used to start a vehicle with a dead battery.

A dead battery can leave you stranded in seconds. Jumper cables allow you to jump-start a disabled vehicle by connecting its electrical system directly to the battery of a running helper car. The cables consist of two thick copper wires insulated in rubber, color-coded red for positive (+) terminals and black for negative (-) ground connections.

Safe connection sequence is critical to prevent dangerous sparks. Connect the red clamp to the dead battery positive terminal first, then the other red clamp to the good battery. Next, connect the black clamp to the good battery negative terminal, and finally, the other black clamp to a clean, unpainted metal ground point on the engine block of the dead car. Start the helper car first, let it run for a few minutes, then attempt to start the dead vehicle.

Frequently Asked Questions

1. Red to dead battery (+). 2. Red to good battery (+). 3. Black to good battery (-). 4. Black to clean metal frame/engine block on the dead car. Disconnect in the exact reverse order.
Connecting the final clamp can create a small spark. Lead-acid batteries release flammable hydrogen gas when charging, and a spark near the battery can cause it to explode.
Thicker cables (lower gauge number) are better. Choose 4-gauge or 2-gauge cables, especially if you need to jump-start larger trucks or SUVs. Cheap 8-gauge or 10-gauge cables will overheat and may not pass enough current.
Yes, but consult the owner's manual. Most hybrids have a dedicated 12V jump-start terminal under the hood, but you should never use a hybrid to jump-start another vehicle, as their electrical converters are not designed for the high current draw.
Back to Glossary

List Your Business on Top Mechanic Services

Get found by customers searching for mechanic services. Join the largest national mechanic services directory.

List Your Business