It is funny how things cycle. We have been doing a bunch of Cisco 4500 installs ranging from 4506’s through the 4510 and even a few 6500s in the mix. And no matter how hard we try we have power issues with them every single time. We either are in a hurry and spec the wrong cables, the client requests the wrong cable, we don’t have the correct power to stage the equipment in our office or the client doesn’t have the right power for the unit. In many cases we temporarily fall back to using 110 power with NEMA 5-15/20T cables and then force the power supplies to combined mode in order to get enough power to bring up the entire chassis.  I should point out that this is usually only good for temp fix and that you should fix your power issue (usually installing bigger circuits) and move back to redundant mode.  But for that quick fix here is the command on a 4500 or 6500 chassis to combine the power supplies:

power redundancy-mode combined

This command should be ran from config mode and once your config is saved it will return to this state after reboot.

And for a bit of extra fun scream out BY THE POWER OF GREYSKULL as you type this in.