Depicted is a close shot of two male electrical plugs on the same cord. This is a dangerous generator hookup. Do not use a cord with two male plugs. It is dangerous because one end could be live with electricity and just be laying on the ground.

Dangerous Generator Hook-Ups

Square D generator sub-panel completed and labeled

Generator Sub-Panel Installation

Completed generator sub-panel with a Square D generator interlock between the utility power main circuit breaker and the generator circuit breaker

Wired Generator Sub-Panel

The spines of a few National Electrical Code books

Free National Electrical Code