Naval ships require several miles of cable to supply power, from its source, throughout the ship. Electrician apprentices learn to install, operate and test electrical systems onboard ships. These systems include lighting, power distribution, machinery, interior communications, fire control/weapons systems, testing, and nuclear plant work. They will work with drawings to devise a plan for their jobs, so they can lay off equipment location and cable runs. Electricians construct and install various electrical components and are required to complete a rigorous series of electrical theory courses to complement on-the-job training.