Rated Capacity
The maximum load a crane can safely lift at a given configuration, as specified by the manufacturer's load chart.
In Detail
Rated capacity is the maximum load that a crane is designed to handle safely at a specific configuration of boom length, boom angle, operating radius, and counterweight/outrigger setup. It is determined by the manufacturer and published in the crane's load chart. Operating at or near rated capacity requires extreme care, and most companies have policies limiting routine lifts to 75-85% of rated capacity. Exceeding rated capacity can cause structural failure, tip-over, or collapse. Rated capacity accounts for the weight of the hook block, rigging hardware, and any attachments — operators must subtract these from the chart capacity to determine the actual load they can pick.
Related Terms
Load Chart
A manufacturer-provided chart showing the maximum safe lifting capacities at various boom lengths and radii.
Critical Lift
A crane lift that exceeds a specified percentage of rated capacity or involves unusual hazards requiring extra planning.
Load Moment Indicator (LMI)
An electronic safety device that monitors crane load, boom angle, and radius to warn operators of overload conditions.
Tip-Over
A catastrophic event where a crane loses stability and overturns, often caused by overloading, ground failure, or improper setup.