Elevate Your Skills with the 2026 NCCER Mobile Crane Challenge – Time to Lift and Conquer!

The question tests the wear limit for crane hook throat openings. OSHA requires that the throat opening not grow by more than 15 percent from its original (new) size. As a hook wears, the gap at the throat increases, which can allow the load to slip or the hook to fail under load. Therefore, if the throat opening becomes more than 15% larger than when the hook was new, the hook must be removed from service or replaced.

In practice, you measure the throat opening with the hook unloaded and closed, compare it to the original dimension stamped or recorded when the hook was new, and calculate the percent increase. If you find a wear increase of 15% or more, remove the hook from service.