How much current does each monoblock pull? (on the rear of the amp somewhere it will say "120V xxxW" W being the power in watts the power supply pulls at maximum draw, not the rated speaker power output.) Then divide watts by 120 to get the current draw.
Also, there's the fuse rating of each monoblock. Let's say it's 8 Amps. Then you can use wire that's rated slightly higher than that, say 10 Amps. 14-Gauge wire is rated at 15A, so this would be about the minimum gauge for this example.
I can't guarantee that you won't have problems with your homemade PC, but if your wire is well-terminated (won't come loose/disconnected), and doesn't run hot, I don't see a problem with it. But if it gets moved around much/bent, some of the small wires of the CAT cable could break, which would put more heat strain on the remaining wires because they're still connected, and the same current has to go through less wires.
Like was said above, the ideal thing is to get some proper power cord to be sure.
Also, there's the fuse rating of each monoblock. Let's say it's 8 Amps. Then you can use wire that's rated slightly higher than that, say 10 Amps. 14-Gauge wire is rated at 15A, so this would be about the minimum gauge for this example.
I can't guarantee that you won't have problems with your homemade PC, but if your wire is well-terminated (won't come loose/disconnected), and doesn't run hot, I don't see a problem with it. But if it gets moved around much/bent, some of the small wires of the CAT cable could break, which would put more heat strain on the remaining wires because they're still connected, and the same current has to go through less wires.
Like was said above, the ideal thing is to get some proper power cord to be sure.