A general safety rule to follow when working with power tools is to:

• A. Keep the tool plugged in and ready for immediate use
• B. Disconnect tools from power when not in use or when changing accessories
• C. Operate at the highest speed possible at all times
• D. Use water to cool down hot components

Answer: (B)

Preventing accidental starts and electrical hazards by removing the power source when you’re not actively using or servicing a tool is the safest, most reliable practice. If the tool remains plugged in, a trigger could be pressed, a switch could stick, or a damaged cord could energize the tool unexpectedly. Unplugging (or removing the battery on cordless tools) ensures the tool cannot start while you’re handling it, changing accessories, or performing maintenance.

This is especially important when changing blades, bits, grinding wheels, or other accessories, because your hands will be near moving parts. Disconnecting eliminates the risk of severe cuts or injuries from a spinning component. It also protects against electric shock or short circuits if there’s a fault in the tool or the cord, or if moisture is present.

The other options introduce clear hazards: keeping the tool plugged in and ready for immediate use invites unexpected starts; operating at the highest speed reduces control and increases the chance of losing control or damaging the work; and using water to cool hot components can cause electric shock and damage to the tool and workpiece.

So the general safety rule is to disconnect from power whenever the tool is not in active use or while changing accessories to keep you safe from start-up and electrical risks.