An uninterruptible power supply (UPS) is used to provide critical devices suitable power for a few minutes when the main source of power goes out. This allows users to save important files and shut down their devices properly.

There may be instances when the UPS will work when it is unplugged but will not work during an actual outage. Aside from ensuring that the devices are connected to the battery backup outlet (and not a surge-only outlet), it is also important to check if the red overload indicator is continuously illuminated. In this situation, the devices are drawing more power than what the UPS can handle. You may need to disconnect non-essential devices from the UPS. It is also advisable to check the battery if it is still working properly. If the battery is not working properly, it will be essential to replace it with a new one.

On the other hand, when the red overload indicator is flashing it may be that the UPS is faulty. It will be necessary to contact the manufacturer if the UPS is still under warranty to get a replacement unit.