Which component must be rated to the Working Load Limit for safe operation?

• A. A tape measure.
• B. A decorative hook.
• C. A shackle.
• D. A wooden block.

Answer: (C)

In rigging, anything that carries a load must be rated to its Working Load Limit so the system remains safe under use. The shackle is specifically a load-bearing connector used to join lines and other hardware in the load path, and it is manufactured and marked with a defined WLL. Because it directly carries the force of the lift, it must be rated to the WLL to prevent failure.

The other items don’t belong in the same load-bearing category. A tape measure is merely a measuring tool and isn’t designed to support lifting or rigging loads. A decorative hook may look like a hook, but it’s not designed or rated for critical rigging use. A wooden block typically doesn’t come with a reliable, certified load rating and can fail unpredictably under load.

Therefore, the shackle is the component that must be rated to the Working Load Limit for safe operation.