[c-nsp] Cisco RPS for 3550 switch

[TCIS List Acct]

We are looking at options to provide redundancy for the internal A/C power 
supply in some 3550-48-EMIs.  It seems that the following RPS models will work:

RPS-300
RPS-675
RPS-2300

We plan to do a 1-1 config (1 RPS for 1 switch), so we are leaning towards the 
RPS-300 for cost reasons.

I've reviewed various threads in the archive, and see where others have had 
problems with the RPS-300's allowing fall-back to the internal A/C power supply 
after it has taken over on the DC source.  Was this an IOS issue, a hardware 
issue with the switch and/or RPS, or ?

Also, I keep seeing this warning in the docs:

"The Catalyst 3550 switch and the Cisco RPS 300 or RPS 675 should be connected 
to the same AC power source."

We had planned to power the internal source from one PDU, and the RPS from 
another PDU (both PDUs are fed by the same UPS source, but we wanted to guard 
against a PDU failure).  What is the real issue here -- and am I asking for 
trouble by ignoring this warning?

TIA.

--Mike