You state: "We have chronic power problems here... blackouts in the winter, and brownouts in the summer.. I want the extra protection... and I don't want to get burnt because some wire vibrates loose sometime in the future."
Look into a large Uninterpretable Power Supply [UPS]. You will be amazed at how much better your computer runs and how few "odd" electrical and electronics problems you have.
What size you ask: Uninterruptible Power Supply (UPS)
Copied from elsewhere:
............I plan to use a UPS on the PC and BOB which will then act on the estop and activate a blinker powered by the same UPS. the UPS is just 10min backup and since I am planning on LED blinker and Atom motherboard processor combo the backup will extend to around15 min.
I will set up the Estop in such a way that any power outage will trigger a estop -, I will also have a delay switch on the mains - before power enters the mains - it will go thru a Omron delay switch - this helps when in our areas there is huge variation in power and where we have external shorts where power gets on / off many times in a few second.
More over one important thing I am planning is to have a Voltmeter placed near your meter box - I have seen in my other machine with servos that any voltage drop will need changes in mach velocity settings. So better safe than sorry.