When is a lock-on switch permissible on a power tool?

A lock-on switch on a power tool is permissible when it can be turned off with a single finger motion. This design feature allows the operator to maintain control of the tool while also ensuring that it can be easily deactivated without needing to reposition their hands. This single-finger operation is critical for safety, as it allows for a quick response in situations where the operator needs to abruptly stop the tool, minimizing the risk of accidents or injuries.

While there may be considerations for other options, such as the nature of the operation or the training of personnel, these do not provide as direct a safety mechanism as the ability to turn off the tool with minimal effort. Manufacturers often design tools with safety features intended for user convenience and safety; however, the ease of turning off a lock-on switch is crucial in ensuring that operators maintain control during use, especially in situations where quick action is necessary.