What safety feature should never be engaged when using a power tool?

The trigger lock is a safety feature designed to prevent accidental activation of a power tool when it is not in use. Engaging this feature ensures that the tool cannot be turned on unintentionally, which is crucial for maintaining safety during transport and storage. However, when actively using the tool, the trigger lock should not be engaged since it would prevent the operator from activating the tool when needed.

In contrast, the other safety features are essential for the safe operation of power tools. The emergency stop allows for immediate shutdown in dangerous situations, the blade guard protects the operator from accidental contact with the cutting tool, and the safety switch is designed to ensure that the tool can only be activated under controlled conditions. Each of these features is important for safeguarding operators and promoting safe usage, while the trigger lock is specifically intended to be disengaged during operation to allow proper tool functioning.