Electrical Safety - Lenovo ThinkCentre M79 Hardware Maintenance Manual

• Place removed covers and other parts in a safe place, away from all personnel, while you are servicing
the machine.
• Keep your tool case away from walk areas so that other people will not trip over it.
• Do not wear loose clothing that can be trapped in the moving parts of a machine. Ensure that your sleeves
are fastened or rolled up above your elbows. If your hair is long, fasten it.
• Insert the ends of your necktie or scarf inside clothing or fasten it with a nonconductive clip, approximately
8 centimeters (3 inches) from the end.
• Do not wear jewelry, chains, metal-frame eyeglasses, or metal fasteners for your clothing.
Remember: Metal objects are good electrical conductors.
• Wear safety glasses when you are: hammering, drilling, soldering, cutting wire, attaching springs, using
solvents, or working in any other conditions that might be hazardous to your eyes.
• After service, reinstall all safety shields, guards, labels, and ground wires. Replace any safety device
that is worn or defective.
• Reinstall all covers correctly before returning the machine to the customer.

Electrical safety

CAUTION:
Electrical current from power, telephone, and communication cables can be hazardous. To avoid
personal injury or equipment damage, disconnect the attached power cords, telecommunication
systems, networks, and modems before you open the computer covers, unless instructed otherwise
in the installation and configuration procedures.
Observe the following rules when working on electrical equipment.
Important: 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 Field Replaceable Units (FRUs)
• 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 exposed electrical circuits, observe the following precautions:
– Ensure that another person, familiar with the power-off controls, is near you.
Remember: 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.
Remember: There must be a complete circuit to cause electrical shock. By observing the above rule,
you may prevent a current from passing through your body.
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ThinkCentre M79 Hardware Maintenance Manual