NAS Alerts Event Code 0031 "ON UPS Power"

I hate for my first post to be a request for assistance (I prefer to lurk and then help when needed if I have the knowledge), but so be it. My EX4100 is plugged into an APC 1500VA UPS, and since I couldn’t find the original CAT5-USB cable, I used a plain “Type A to Type B” USB cable. It was recognized as a USB device under the USB icon on the main menu bar on top of the WD web interface, but I couldn’t find any other settings or configuration options related to it.

The next day (less than 24 hours, but more than 12 hours later), I received a NAS e-mail event warning: Event description: “The system is running on UPS power. 100% power left.” My first thought was that I had a power outage while I was away from home, but there was no corresponding event message telling me I was not running on UPS any longer. Now I am thinking, “well, technically, I’m on UPS all the time if I’m plugged into a battery”. I that all that it is?

Will I be better off with a CAT5-USB cable that originally came with the APC UPS?

I appreciate any insight.


This is a unit designed to work connected to your network. The USB port, is to attach usb drives to the unit for USB backups or safepoints.

As a recommendation, connect the unit using an Ethernet cable.

Regarding the power, it’s better if the unit is connected to a wall outlet directly.

Some computer (NAS) power adapters my not like the UPS (not pure sine wave power output) of the cheaper UPS systems ( which may be why there is a WD recommended list ? )

I think you are always better off using a UPS but the less pure sine wave power only starts when the power fails so best to test.

The power adapters (bricks) are build a lot better now and can work better with UPS systems.

NOTE: I do not use the included 90 watt brick but a better 120 watt unit.