What is the correct sequence to remove jump-start cables after starting the engines?

• A. Turn off the donor battery after starting.
• B. Remove the positive leads first, then negative.
• C. Remove both at the same time.
• D. Remove the negative lead from engine block first, then remove positive leads.

Answer: (D)

When taking jump-start cables apart, break the circuit where it’s safest first. The main safety point is to disconnect the ground (negative) connection before touching the positive connections. The negative lead that’s attached to the engine block serves as the primary ground path. By removing that first, you interrupt the current path and reduce the chance of a spark near the battery where hydrogen gas could be present.

After the ground is removed, you can safely detach the remaining leads, finishing with the positive connections. This order minimizes arcing and the risk of a short or ignition near the battery.

Turning off the donor battery or removing the positive leads first increases the chance of a spark near the battery or creates a temporary path for current that’s less safe. Removing both cables at once isn’t feasible in practice, and the grounded-first rule is the safer, standard approach.