What power cord does a WD16001032 hard drive use

Depends on what you want. If it is important for you that there is no downtime when one of your disks fails (and a disk fail has a much higher probability than an electronics/controller fail), use a RAID.

If it is more important that your data is safe (i. e. a backup), use separate disks and sync them manually (maybe even keep multiple generations as you can always accidentally delete important files).

A RAID is not a backup (in the rare case that the electronics fail). You will need a backup (at least if you think your data is somewhat important), but you will only need a RAID if uptime is important to you.

"...part or all of their backup solution."

USB HDDs for part of the solution is okay. For all of the solution, it's not a good idea.

When you plug in your USB HDD, your entire backup medium is now online and writable, on the same machine which has your primary data.

In the event of:

• a glitch in your backup software
• an electrical failure
• a virus
• human error
• fire or flood

You could lose all your data, even your backups.

One poor-man's solution would be to use two HDDs, keeping one off-site and off line (e.g., at a friend's house).

The disks are reliable. Some USB electronics are flaky, so test your backups.