2-12 Installation PreparationsSafety PrecautionsTo avoid any device impairment and bodily injury caused by improper use, observe these rules:z Before cleaning the switch, plug out the power cord of the switch first. Do not clean the switch withwet cloth or liquid.z Do not place the switch near water or in a damp environment. Prevent water or moisture fromentering the switch chassis.z Do not place the switch on an unstable case or desk. The switch might be damaged severely incase of a fall.z Ensure proper ventilation of the equipment room and keep the ventilation vents of the switch free ofobstruction.z Connect the yellow-green protection PGND cable before power-on.z Make sure that the operating voltage is in the range labeled on the power of the switch.z Do not open the chassis to avoid electrical shocks when the switch is operating or just when theswitch is powered off.Installation SiteThe 3Com Baseline Switch 2900 Family must be used indoors. You can mount the switch in a rack or ona workbench, but make sure:z Adequate clearance is reserved at the air inlet/exhaust vents for ventilation.z The rack or workbench has a good ventilation system.z The rack is sturdy enough to support the device and its accessories.z The rack or workbench is well earthed.To ensure normal operation and long service life of your switch, install it in an environment that meetsthe requirements described in the following subsections.Temperature/HumidityYou must maintain a proper temperature and humidity in the equipment room. Long-term high humiditymay lead to bad insulation, electricity leakage, mechanical property changes, and metal corrosion.However, if the relative humidity is too low, captive screws may become loose as the result ofcontraction of insulation washers and static electricity may be produced in a dry environment tojeopardize the circuits on the device. A high temperature is the most undesirable condition, because itaccelerates the aging of insulation materials and thus significantly lowers reliability and service life ofthe switch.For the temperature and humidity requirements of different models, refer to Table 2-1 on page 2-2.CleannessDust is a hazard to the operating safety of your device. The dust accumulated on the chassis can beadsorbed by static electricity and result in poor contact of metal connectors or metal contact points.