Conntek 20601 L14-30 Generator Extension Cord, 25 ft

If a truck can export 240V, this is how it reaches a job. Ten-gauge copper across four conductors handles the full 30 amps without the voltage drop that makes cheaper cords warm and inefficient, and the molded ends mean nothing to come loose in a wet parking lot. Available in 10, 25, 40, 50, and 100 foot lengths — buy the shortest one that reaches, because every extra foot costs you voltage.