Recommended AC power line sizes

When installing your storage system, you must determine the AC power line lengths running from the storage system to the power source.

By properly designing longer AC power feeds, you can preserve voltage levels to the equipment. The longer power feeds—the wiring from the breaker panel to the power strip, which supplies power to the storage system 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 tables list the recommended conductor size for 2 percent voltage drop for a particular distance measured in feet (taken from the Radio Engineer's Handbook). The circuits in the following tables are described in American Wire Gauge (AWG) measurements:
110V, single-phase 20A circuit 30A circuit 40A circuit 50A circuit
25 feet 12 AWG 10 AWG 8 AWG 8 AWG
50 feet 8 AWG 6 AWG 6 AWG 4 AWG
75 feet 6 AWG 4 AWG 4 AWG 2 AWG
220V, single-phase 20A circuit 30A circuit 40A circuit 50A circuit
25 feet 14 AWG 12 AWG 12 AWG 10 AWG
50 feet 12 AWG 10 AWG 8 AWG 8 AWG
75 feet 10 AWG 8 AWG 6 AWG 6 AWG

The following table lists the approximate equivalent wire gauge (AWG to Harmonized Cordage).

AWG 8 10 12
Harmonized, mm-mm

mm-mm = millimeter squared

4.0 2.5 1.5