Which component is NOT recommended for use in a fall-arrest system?

The component that is not recommended for use in a fall-arrest system is a single-strap belt. This type of belt does not provide adequate support or safety features necessary to protect an individual from falls when working at heights. A full-body harness, lineman's-style belt, and suspension relief strap are all designed specifically to distribute weight evenly and offer the necessary support in case of a fall.

A full-body harness wraps around the torso and legs, helping to prevent injury during a fall by distributing forces across the body. Lineman's-style belts are used in specific applications such as climbing where they can be paired with other safety gear but still provide greater stability than a single-strap option. A suspension relief strap is critical in a fall situation, allowing a person to relieve pressure on their legs after a fall and prevent suspension trauma.

Using a single-strap belt can pose serious risks, as it may not effectively support the body if a fall occurs, leading to potential injury. Therefore, it is crucial to utilize components in fall-arrest systems that are specifically designed for safety and efficacy in preventing injuries.