Independent Electrical Contractors (IEC) Year 4 Practice Exam

When the boom of a telescopic material handler is extended, the load capacity reduces. This happens because extending the boom increases the lever arm between the load and the machine’s base, which raises the tipping moment the machine must resist. The stabilizers (outriggers), wheelbase, and fixed counterweight have to handle a larger tipping force as the load moves farther away horizontally. Even though the lift height might change the dynamics, the most critical factor for the capacity at a given reach is the increased moment caused by the greater distance from the base. That’s why the rated capacity is highest with little or no extension and decreases as the boom reaches farther out. Always consult the machine’s load capacity chart for the exact reach and boom angle, as different configurations will show different allowable loads, but the general trend remains: capacity goes down with extension.