power rating

Anyone know what the input power rating (mains draw) is in Watts of a 5N when connected to 240VAC? I am wanting to size a UPS for 2x 5N’s and want to know if a APC BR1500GI is big enough.

Depends on the number and type of the drives installed, mostly. From the official specifications, 5N comes with a PSU rated for 150W max output, so let’s make it ~190W peak draw taking efficiency into account but that’d be really the worst case scenario. HDDs draw their peak current during spin-up. In practice, it will be much, much less during regular operation.

For what it’s worth, here are some measurements I took for my 4-bay Gen. 2 Drobo loaded with 4 different HDDs back in the day:
Active (chkdsk operation): 37W
Idle (disks spinning, doing nothing): 32W
Disks spun down, fan running: 13W
Unit in standby: 8W
(PSU efficiency not taken into account, so allow for some +20% tops for heating of your power brick)

5N is much more powerful (and thus more power-hungry as well) than my 2nd Gen was, but this won’t affect the main contributor to the overall power consumption which is the drives themselves.

hi, just a thought, if the environment is very hot, (for weather reasons or bad drive reasons), and the fan has to spin at its fastest, then that might add to the power draw as well?

Yes, insignificantly.

ok thanks zbig