When protecting your equipment with an uninterruptible power supply (UPS), you need more power than the equipment itself requires. This is due to the extra power required to continue running your device(s) and recharge the uninterruptible power supply’s batteries after a power outage.
Sometimes this means that you will need a different socket for the UPS to plug into that allows more power to be drawn. For example, a high end server may only draw 1,600 watts and require a NEMA 5-15R (standard socket with 1,875 watt maximum), but when adding an uninterruptible power supply with adequate capacity to run the server and recharge the UPS’ batteries, the correct uninterruptible power supply will require a NEMA 5-20R (20 amp socket with 2,500 watt maximum) for input. In this instance, the UPS will have a NEMA 5-15R on the back of it for the server to plug into, but the UPS itself will require a NEMA 5-20R for its input.