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This chapter describes how to prepare your site for the installation of the switch and contains these sections:
For detailed information about cabling requirements, see "Gigabit Port Configuration."
Planning a proper location for the switch and the layout of your equipment rack or wiring closet is essential for successful system operation. You should install the switch in an enclosed, secure area, ensuring that only qualified personnel have access to the switch and control of the environment. Equipment placed too close together or inadequately ventilated can cause system overtemperature conditions. In addition, poor equipment placement can make chassis panels inaccessible and difficult to maintain.
The switch operates as a standalone system mounted in a rack in a secure wiring closet. It requires a dry, clean, well-ventilated, and air-conditioned environment. To ensure normal operation, maintain ambient airflow. If the airflow is blocked or restricted, or if the intake air is too warm, an overtemperature condition can occur. The switch environmental monitor can then shut down the system to protect the system components.
To ensure normal operation and avoid unnecessary maintenance, plan your site configuration and prepare your site before installation. After installation, make sure the site maintains an ambient temperature of 0 to 40ºC (32 to 104ºF). It is essential to keep the area around the chassis as free from dust and foreign conductive material (such as metal flakes from nearby construction activity) as is possible.
Multiple switches can be rack-mounted with little or no clearance above and below the chassis. However, when mounting a switch in a rack with other equipment, or when placing it on the floor near other equipment, ensure that the exhaust from other equipment does not blow into the intake vent of the chassis.
Cooling air is drawn in through the front side and exhausted through the rear of the chassis. Keep the front and rear sides clear of obstructions, including dust and foreign conductive material, and away from the exhaust ports of other equipment.
Appendix A, "Specifications," lists the operating and nonoperating environmental site requirements for the switches. To maintain normal operation and ensure high system availability, maintain an ambient temperature and clean power at your site. The environmental ranges listed in Appendix A are those within which the switch will continue to operate; however, a measurement that approaches the minimum or maximum of a range indicates a potential problem. You can maintain normal operation by anticipating and correcting environmental anomalies before they exceed the maximum operating range.
This section describes the installation site power requirements for the Catalyst 4912G switch. The power requirements for the site should be verified before you install the switch.
Follow these requirements when preparing your site for the Catalyst 4912G switch installation:
 | Warning This product relies on the building's installation for short-circuit (overcurrent) protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15A U.S. (240 VAC, 10A international) is used on the phase conductors (all current-carrying conductors). |
Follow these precautions when preparing your site for the Catalyst 4912G switch installation:
 | Caution The total maximum load on each AC-input power circuit must be within the rating of the wiring and breaker. An overload of input power can result if this requirement is not met. |
| Warning This equipment is intended to be grounded. Ensure that the host is connected to earth ground during normal use. |
Follow these guidelines when setting up the site wiring. When planning the location of the new system, consider electromagnetic interface (EMI), the distance limitations for signaling, and connector compatibility. Strong EMI, especially when caused by lightning or radio transmitters, can destroy the signal drivers and receivers in the switch and can create an electrical hazard by conducting power surges through lines and into equipment.
When wires are run for any significant distance in an electromagnetic field, radio frequency interference (RFI) can occur between the field and the signals on the wires.
Power requirements might be useful for planning the power distribution system needed to support the switches. Heat dissipation is an important consideration for sizing the air-conditioning requirements for an installation. Refer to "Specifications," for the power and heat ratings for a Catalyst 4912G switch.
If DC grounding is required, installation is approved for use with copper connectors only. Attach the chassis ground M4 pemnuts to the central office or other interior ground system with number 6 AWG wire (the larger gauge ground wire is used when the switch is further away from the ground location). The chassis uses two threaded M4x.7 chassis ground pemnuts. These M4 pemnuts connect directly to the central office or other interior ground systems and are located on the rear of the chassis. The ground chassis M4 pemnuts require M4 bolts and locking hardware, which are not included.
Table 3-1 lists the site planning activities that you should perform before you install the Catalyst 4912G switch. Completing each activity helps ensure a successful switch installation.
| Task No. | Planning Activity | Verified By | Time | Date |
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1 | Space evaluation: Space and layout |
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2 | Environmental evaluation: Ambient temperature |
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3 | Power evaluation: Input power type |
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4 | Grounding evaluation: Circuit breaker size |
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5 | Cable and interface equipment evaluation: Cable type |
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6 | EMI evaluation: Distance limitations for signaling |
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Posted: Thu Apr 8 13:46:25 PDT 1999
Copyright 1989-1999©Cisco Systems Inc.