Any dangers or concerns doing this?

I run a home theater and separate stereo system in a room where the electronic stacks are separate but they share the same main speakers. When swapping systems I disengage the breaker on the amp not in use and change speaker cables. I want to run my 5 channel amp to the 20 amp circuit that my stereo amp uses without having to purchase a new cable for the run. My 5 channel amp uses the c20 style iec output while my pass Labs uses the more common c14 style. I see there are adaptors for this and I am thinking of doing that in lieu of buying and running another cable. This way when switching systems I can just unplug the one amp and put the same power cord in the other amp. Thanks for any input.
By repeatedly inserting and removing the cables you will be producing a great amount of wear and tear on both the male and female ends of this connection. At some point they will become loose and worn and would need to be replaced. Furthermore, due to this wear, it could cause the supplied voltage to be intermittent or variable which could damage the equipment.
As an example, You could build a box with parts from Home Depot ETC which would have 2 receptacles and two wall switches conformed as a power strip. This would handle your switching problem. 

I am really curious. Why not just keep the stereo amp for both, and use the 5 channel amp for center and surround duties? 
I would concur with squires, just use the Pass Labs for both and only turn on the 5 channel for HT just plug the L&R fronts into the Pass Labs, and run the Pass Labs to the preout L&R on the 5 channel. for HT run both and for stereo only turn on the Pass Labs.