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Observe the following rules when working on electrical equipment.
Use only approved tools and test equipment. Some hand tools have handles covered with a soft material
that does not insulate you when working with live electrical currents.
Many customers have, near their equipment, rubber ﬂoor mats that contain small conductive ﬁbers to
decrease electrostatic discharges. Do not use this type of mat to protect yourself from electrical shock.
Find the room emergency power-off (EPO) switch, disconnecting switch, or electrical outlet. If an electrical
accident occurs, you can then operate the switch or unplug the power cord quickly.
Do not work alone under hazardous conditions or near equipment that has hazardous voltages.
Disconnect all power before:
Performing a mechanical inspection
Working near power supplies
Removing or installing main units
Before you start to work on the machine, unplug the power cord. If you cannot unplug it, ask the customer
to power-off the wall box that supplies power to the machine, and to lock the wall box in the off position.
If you need to work on a machine that has
electrical circuits, observe the following precautions:
Ensure that another person, familiar with the power-off controls, is near you.
Another person must be there to switch off the power, if necessary.
Use only one hand when working with powered-on electrical equipment; keep the other hand in your
pocket or behind your back.
An electrical shock can occur only when there is a complete circuit. By observing the above
rule, you may prevent a current from passing through your body.
When using testers, set the controls correctly and use the approved probe leads and accessories for
Stand on suitable rubber mats (obtained locally, if necessary) to insulate you from grounds such as
metal ﬂoor strips and machine frames.
Observe the special safety precautions when you work with very high voltages; Instructions for these
precautions are in the safety sections of maintenance information. Use extreme care when measuring
Regularly inspect and maintain your electrical hand tools for safe operational condition.
Do not use worn or broken tools and testers.
that power has been disconnected from a circuit. First,
that it has been powered off.
Always look carefully for possible hazards in your work area. Examples of these hazards are moist ﬂoors,
nongrounded power extension cables, power surges, and missing safety grounds.
Do not touch live electrical circuits with the reﬂective surface of a plastic dental mirror. The surface is
conductive; such touching can cause personal injury and machine damage.
Do not service the following parts
with the power on
when they are removed from their normal operating
places in a machine:
Power supply units
Blowers and fans
Similar units to listed above
This practice ensures correct grounding of the units.
If an electrical accident occurs:
Hardware Maintenance Manual
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