Jump Start (vehicle) - Jumper Cables (Jump Leads)

Jumper Cables (Jump Leads)

For other uses, see Jumper cable (disambiguation).

Many motorists carry jumper cables (known in the UK as jump leads) which consist of a pair of heavy gauge, insulated wires with alligator clips at each end. Jumper cables are available in various lengths. The size of copper conductors varies from about #10 AWG for light duty sets, to #1 AWG. The alligator clips generally have color-coded, vinyl-coated (PVC) insulation to prevent electrical short circuits. Most clips fit both top- and side-mounted battery terminals. Top-quality clips are made of solid copper; lesser-quality are made of material such as copper-plated steel. Jumper cables are marked by black (-) and red (+) handles, representing the two polarities of the automobile's direct current system. Interchanging the polarities will cause damage to one or both automobiles, possibly including blown electrical fuses and circuit boards, and could cause a battery explosion. Car manuals recommend connecting the negative (black) cable last and disconnecting it first, since charging may produce hydrogen gas, which could explode if there is a spark; if this ruptured the battery casing, it would then spray Sulfuric acid, possibly over the person performing the jump start (see acid burn for consequences). Connecting the positive (red) cable while the negative cable is connected may also cause a spark and battery explosion.