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Prevention of electric shock
● Before starting work, make sure that there is no potential electrical hazard in the maintenance area.
Example: Insufficient grounding line or a wet floor
● Before starting work, check the location of the emergency power-off switches and how to operate them.
● Unless otherwise specifically instructed, isolate the machine from all power sources before starting
maintenance. Turn off not only the power switches on the machine but also the switch on the distribution
panel.
After turning off the switch on the power distribution panel, attach a notice saying Do not turn on this switch
on the power distribution panel. If the power distribution panel is equipped with a lockout device, turn off the
switch on the power distribution panel, lock the device, and then bring the key with you.
If you are resuming maintenance work performed by someone else, do not assume that the power is off.
Make sure that the above-mentioned conditions, such as switches turned off, are satisfied. If necessary, use a
measurement tool to ensure that the power is off.
● Some parts in the machine remain charged for a certain time even after the power supply to the machine is
disconnected. (Follow the displayed instructions).
● When working on a machine which has a grounding terminal, make sure that the terminal is properly
connected to the facility's ground.
● When working near an exposed live electric circuit, do not work alone. Work with another person who can
immediately turn off the power.
● To prevent electric shock during work, do not wear any metallic items or an accessory such as a wristwatch
with a metallic surface. If you wear eyeglasses with a metallic frame, take care not to let the frame touch an
uninsulated surface.
● Make sure that your hands and arms are dry.
● Use only one hand when it is necessary to work near an exposed live electric circuit. This mitigates the risk
of current passing through your heart if you accidentally touch the circuit.
● Do not use a dental mirror near an exposed live electric circuit. The mirror surface is conductive and can
become hazardous even if the mirror is made of plastic.
● Unless otherwise specifically instructed, do not supply power to any subassembly such as a power supply
unit or a motor while it is removed from the machine.
S-4
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