U. P. aSked (You people asked): Big Box UPSes dont work on servers

A frequent question from customers is... I bought a 1500 UPS from a big box store, but its not able to handle my two servers each with 500watt power supplies.

• First off, nearly every big box retailer only sells APC backUPS or SmartUPS SC units, which are junk.  
• Second, those junky units use a technology that causes them to shut off during overload conditions.
• Third, your server probably uses a PFC type power supply which tend to have a high inrush current, which these junky UPSes think are overloads.
• Fourth, those junky UPSes require you to size your UPS at 125% of the rated Power supply wattage.  (meaning a two servers with 500watts power supplies need at least 1250watts or a 1700va UPS)

The good news, is that real Smart UPS units from us can handle your server's power supplies at the actual load, without any necessary upsizing.   So two servers with 500 watt power supplies probably can use a 1000va SmartUPS (100b), since the actual max load of the servers is about 300watts and the 100b is rated for 670watts.

Bottomline, all the units we sell are rated for the PFC type power supplies and need only be sized based on their true load.  Of course call us or visit APC's site for actual loads.

Read more about PFC from APC's white paper