Guidelines For Servicing Electrical Equipment - Lenovo System x3750 M4 Installation And Service Manual

To inspect the product for potential unsafe conditions, complete the following steps:
1. Make sure that the power is off and the power cord is disconnected.
2. Make sure that the exterior cover is not damaged, loose, or broken, and observe any sharp edges.
3. Check the power cord:
• Make sure that the third-wire ground connector is in good condition. Use a meter to measure
third-wire ground continuity for 0.1 ohm or less between the external ground pin and the frame ground.
• Make sure that the power cord is the correct type, as specified in "Power cords" on page 213.
• Make sure that the insulation is not frayed or worn.
4. Remove the top cover.
5. Check for any obvious non-Lenovo alterations. Use good judgment as to the safety of any non-Lenovo
alterations.
6. Check inside the server for any obvious unsafe conditions, such as metal filings, contamination, water
or other liquid, or signs of fire or smoke damage.
7. Check for worn, frayed, or pinched cables.
8. Make sure that the power-supply cover fasteners (screws or rivets) have not been removed or tampered
with.

Guidelines for servicing electrical equipment

This section contains guidelines to follow when you service electrical equipment.
Observe the following guidelines when you service electrical equipment:
• Check the area for electrical hazards such as moist floors, nongrounded power extension cords, power
surges, and missing safety grounds.
• Use only approved tools and test equipment. Some hand tools have handles that are covered with a soft
material that does not provide insulation from live electrical currents.
• Regularly inspect and maintain your electrical hand tools for safe operational condition. Do not use
worn or broken tools or testers.
• Do not touch the reflective surface of a dental mirror to a live electrical circuit. The surface is conductive
and can cause personal injury or equipment damage if it touches a live electrical circuit.
• Some rubber floor mats contain small conductive fibers to decrease electrostatic discharge. Do not use
this type of mat to protect yourself from electrical shock.
• Do not work alone under hazardous conditions or near equipment that has hazardous voltages.
• Locate the emergency power-off (EPO) switch, disconnecting switch, or electrical outlet so that you can
turn off the power quickly in the event of an electrical accident.
• Disconnect all power before you perform a mechanical inspection, work near power supplies, or remove
or install main units.
• Before you work on the equipment, disconnect the power cord. If you cannot disconnect the power
cord, have the customer power-off the wall box that supplies power to the equipment and lock the
wall box in the off position.
• Never assume that power has been disconnected from a circuit. Check it to make sure that it has been
disconnected.
• If you have to work on equipment that has exposed electrical circuits, observe the following precautions:
– Make sure that another person who is familiar with the power-off controls is near you and is available to
turn off the power if necessary.
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