[c-nsp] Redundant power supply onto a WS-4912

[jcovini at free.fr]

I have a WS-C4912 with the following PS1 inserted :
PS1-Type internal total 400W.

We just received a backup unit for PS2
PWR-C49-300DC/2 :  300-Watt DC  -Catalyst 4900

I would like to hotplug it, but
-> Is it possible
-> Is it safe

Im always paranoid when it comes to hotplug.....