Many times when you blow a breaker, lose power, or even if the cord just becomes unplugged, you forget to turn off the tool. This can lead to the dangerous situation where the tool restarts unattended after you restore power. This may not always be a problem, but what if you left stock in contact with a blade or you left the belt sander face down on the table?
Woodcraft amusingly describes this scenario in their writeup of the SafetyGate:
Most belt-sander races aren’t sanctioned events. Accidentally pull the trigger, set the tool on your bench, and when as you plug the cord into the outlet, you’ve got yourself a track-side seat.
Sanctioned belt sander races are fun, but when an accidental trigger pull turns your workbench into the drag strip, the event ends with a damaged workpiece or trashed tool. Considering the potential of other tools, it’s easy to imagine how an unexpected start–when you’re plugging it into an outlet, or resetting a blown fuse–can be much worse than an amusing anecodote [sic].
Plug the SafetyGate into the outlet and your tool into the SafetyGate. If you leave the tool on when the power goes out, its patented sensor technology recognizes this and prevents current from flowing to the tool when power is restored. When this condition happens a yellow LED on the device turns on and you need to switch the tool off then back on again to make it work.
SafeStartSystems sells two versions of their SafetyGate product — a consumer and a professional model. The consumer model retails for $19 and the professional model retails for $24. Both have a 15A maximum rating, but the professional model meets several national standards including OSHA, NFPA and CSA standards. Plus the black and yellow coloring of the professional version looks much cooler.