Warning | This equipment must be grounded. Never defeat the ground conductor or operate the equipment in the absence of |
| | a suitably installed ground conductor. Contact the appropriate electrical inspection authority or an electrician if |
| | you are uncertain that suitable grounding is available. Statement 1024 |
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Warning | This unit might have more than one power supply connection. All connections must be removed to de-energize the |
| | unit. Statement 1028 |
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Warning | This product relies on the building’s installation for short-circuit (overcurrent) protection. Ensure that the |
| | protective device is rated not greater than: AC power supplies 20 A and DC power supplies 40 A. Statement 1005 |
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Before you begin, read these important notices:
•The color coding of the DC-input power supply leads depends on the color coding of the DC power source at your site. Typically, green or green/yellow is used for ground (GND), black is used for -48V on negative (–) terminal and red is used for RTN on the positive (+) terminal. Make certain the lead color coding you choose for the DC-input power supply matches lead color coding used at the DC power source.
•For DC input power cables, select the appropriate wire gauge based on the National Electrical Code (NEC) and local codes for 60-amp service at nominal DC input voltage (–48/–60 VDC). Three pairs of cable leads, source DC (–) and source DC return (+), are required for each power distribution unit (PDU). These cables are available from any commercial cable vendor. All input power cables for the chassis should have the same wire gauge and cable lengths should match within 10 percent of deviation.
Each DC input power cable is terminated at the PDU by a cable lug. The cable lugs must be dual-hole, and have a 45-degree angle tongue. They must be able to fit over #10 power terminal stud.
Note DC input power cables must be connected to the PDU terminal studs in the proper positive (+) and negative (–) polarity. In some cases, the DC cable leads are labeled, which is a relatively safe indication of the polarity. However, you must verify the polarity by measuring the voltage between the DC cable leads. When making the measurement, the positive (+) lead and the negative (–) lead must always match the (+) and (–) labels on the PDU.
•An earth ground cable is required for each DC PDU. We recommend that you use at least 6-AWG multistrand copper wire. This wire is not available from Cisco Systems; it is available from any commercial cable vendor.
