Apple Workgroup Clusters ship with various uninterruptible power supply (UPS) sizes. Some of these UPS systems include plug shapes that may not be available at your installation site. Read on to learn about plug shapes and electrical current considerations..
| Type | Plug | Socket |
| NEMA 5-15 This is the most common plug shape in the U.S. and Canada. It has two vertical prongs, one slightly larger than the other, and a third, round prong for ground. It supports 15 amps of current at 120V. |
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| NEMA 5-20 This plug, which supports 20 amps of 120V current, is also common in institutional environments. Compared to the NEMA 5-15, one of the NEMA 5-20 plug's top two prongs is rotated 90 degrees. |
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| NEMA L5-30 This plug is typically found in server rooms or in places where it has been specially installed for high-current equipment. This plug type is used on circuits that support 30 amps at 120 volts. |
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Each Xserve G5 Cluster Node requires approximately 2 amps of current at 120V. You should ensure that the outlet you're using is capable of sustaining the total current of your cluster system, including Xserves, switches, and fans.
The current requirements for each device are documented in the product manual. The current (in amps) required by the servers, which will make up the majority of your circuit load, is equal to the number of Xserve G5 servers multiplied by 2 (at U.S. and Canadian voltage). You should also leave some headroom in your circuit capacity—typically, about an amp or two per circuit. If you do not have an outlet capable of supporting the load of your entire Apple Workgroup Cluster, you must split the systems across two or more independent circuits.
Beginning in December 2004, all Apple Workgroup Cluster systems now ship with APC Smart-UPS 1000VA UPSs. You should connect only the head node of your cluster to this UPS. Cluster nodes are not as essential to protect with the UPS since the risk of data loss is highest on the head node during a power failure. (No non-volatile data is stored on cluster nodes.) APC Smart-UPS 1000VA UPSs have NEMA 5-15 connectors.
Important: Information about products not manufactured by Apple is provided for information purposes only, and does not constitute Apple's recommendation or endorsement. Please contact the vendor for additional information.
See also technical document 86694: Xserve G5: Power consumption and thermal output (BTU) information