Longer AC power feeds need to be properly designed to preserve voltage levels to the equipment. The wiring from the breaker panel to the power strip, which supplies power to the storage appliance and disk shelves, can often exceed 50 feet.
Note
Total AC wire length = breaker to wall or ceiling outlet + extension cable or ceiling drop.
The following table lists the recommended conductor size for 2% voltage drop for a particular distance in feet (taken from the Radio Engineer's Handbook).
The following table list the approximate equivalent wire gauge (American Wire Gauge (AWG) to Harmonized Cordage).
1 mm-mm = millimeter squared
To calculate the maximum combined length of the positive and negative wires between the DC source and DC power supplies, use the following variable definitions:
The following two examples show how to calculate the maximum combined length of the positive and negative wires that connect the DC power supply to the DC source.
This example uses the following given values.
For example, if you have a 12 gauge wire, solid strand, at room temperature, use the following calculation.
1 Data from Alpha Wire, wire manufacturer
2 Combined positive and negative run
This example uses the following given values.
For example, if you have a solid strand 12 gauge wire at room temperature, use the following calculation.
1 Data from Alpha Wire, wire manufacturer
2 Combined positive and negative run
If you need a longer run for your combined positive and negative DC wires, choose a wire with a lower resistance and calculate the total cable length. For example, a solid #10 AWG has a lower DC resistance than a solid #12 AWG.
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Part No. 210-00134
File: appb2.htm
Last updated: 07/17/02 02:28:09
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