National Commission for the Certification of Crane Operators (NCCCO) Mobile Crane Practice Exam

When performing duty cycle work, by what percentage must the load chart be reduced?

1. 10%

2. 20%

3. 30%

4. 50%

The correct answer is: 20%

When performing duty cycle work with a mobile crane, it is essential to recognize that the load-carrying capacity decreases compared to standard lift operations. As a general industry practice, load charts for cranes are often reduced by a percentage to account for the variations and stresses involved in duty cycle activities, such as digging, dragging, or other continuous lifting operations. In this case, a reduction of 20% is standard because performing duty cycle work typically subjects the crane to dynamic loading conditions that differ from those encountered in standard lifts. This reduction helps ensure safety and stability, as the loads during these activities can cause more wear and stress on the crane, potentially leading to failure if the full lifting capacity were used. By applying this 20% reduction, operators can better manage their lifts and ensure they are operating within safe parameters, ultimately maintaining equipment integrity and worker safety throughout the duty cycle operations.