Don’t do double duty as spotter and ground rigger
A crane operator was putting up steel beams for a building annex. His brother-in-law was acting as both spotter and ground rigger, attaching the steel beams to the crane. A high-voltage line ran by the job site. The crane operator reminded his relative to help him keep the crane at least 15 feet* from the line, but something went wrong. The brother-in-law signaled the crane to get too close to the line, and when he grabbed the crane cable to attach a steel beam, he was electrocuted. (Source: Worker Beware video)
*Today, per OSHA regulations, this clearance would be at least 20 feet.