Electrical safetyCAUTION:Electrical current from power, telephone, and communication cables can behazardous. To avoid personal injury or equipment damage, disconnect theattached power cords, telecommunication systems, networks, and modemsbefore you open the server covers, unless instructed otherwise in theinstallation and configuration procedures.Observe the following rules when working on electrical equipment.Important: Use only approved tools and test equipment. Some hand tools havehandles covered with a soft material that does not insulate you whenworking with live electrical currents.Many customers have, near their equipment, rubber floor mats thatcontain small conductive fibers to decrease electrostatic discharges. Donot use this type of mat to protect yourself from electrical shock.v Find the room emergency power-off (EPO) switch, disconnecting switch, orelectrical outlet. If an electrical accident occurs, you can then operate the switchor unplug the power cord quickly.v Do not work alone under hazardous conditions or near equipment that hashazardous voltages.v Disconnect all power before:– Performing a mechanical inspection– Working near power supplies– Removing or installing main unitsv Before you start to work on the machine, unplug the power cord. If you cannotunplug it, ask the customer to power-off the wall box that supplies power to themachine and to lock the wall box in the off position.v If you need to work on a machine that has exposed electrical circuits, observethe 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, ifnecessary.– Use only one hand when working with powered-on electrical equipment; keepthe other hand in your pocket or behind your back.Remember: There must be a complete circuit to cause electrical shock. Byobserving the above rule, you may prevent a current from passing throughyour body.– When using testers, set the controls correctly and use the approved probeleads and accessories for that tester.– Stand on suitable rubber mats (obtained locally, if necessary) to insulate youfrom grounds such as metal floor strips and machine frames.Observe the special safety precautions when you work with very high voltages;these instructions are in the safety sections of maintenance information. Useextreme care when measuring high voltages.164 BladeCenter JS20 Type 8842: Hardware Maintenance Manual and Troubleshooting Guide
