[c-nsp] Redundancy vs. Paranoia

[Jeff Kell]

Bill Wichers wrote:

> I would recommend each power supply be placed on a seperate circuit
> though, since I have seen many cases where a single circuit will trip and
> if your power supplies are on different circuits you won't go down if a
> single circuit fails. Best is to have each supply on a seperate UPS and
> generator, but that's not always possible. 

While the "each power supply be placed on a separate circuit" part is
par for the course for multiple supplies in a given device, one thing
often overlooked [mea culpa, ONCE], is to place more than one device on
the same circuit, especially UPS feeds, where the distribution layer is
often "sparse" at in smaller installations.  I had a power supply in a
6509 fail in a manner that tripped the breaker, which caused a power
outage to some smaller switches that were plugged into the same circuit.
Guess I asked for that one.

Jeff