What is “rated capacity” and why should it never be exceeded during a lift?

• A. It is the maximum legal load allowed by regulation; exceeding it results in fines.
• B. It is the maximum weight that can be lifted without any energy consumption increase.
• C. It is the maximum load the crane can safely lift at a given configuration; exceeding it risks tipping, structural failure, and severe injury or death.
• D. It is the weight of the crane itself.

Answer: (C)

Rated capacity is the maximum load a crane can safely lift for the current configuration, including factors like boom length and angle, radius, outriggers, and counterweights. It comes from the crane’s design and the manufacturer’s load charts, which show how capacity changes as the setup changes. This limit is a safety boundary that accounts for the stresses the crane can handle without risk of tipping, structural damage, or failure.

Exceeding it creates dangerous conditions: the crane can become unstable and tip over, the boom or other components can bend or fail, and workers nearby face severe injury or death from a dropped load. The rated capacity also considers dynamic effects such as the load’s movement and inertia, so staying within the limit keeps the lift controlled and predictable.

Always check the current configuration against the load chart before lifting, ensure ground and setup are solid, and use appropriate rigging and signaling to maintain a safe operation.