MacPro4,1 8 core Intel Xeon 2.26 GHz, 8 GB RAM

I bought an 8 core MP from the local Apple retail store (08/2009). When I power up or wake the machine from sleep, my office lights flicker. (My vacuum cleaner does the same thing when I switch it on.) This happens with or without the dedicated 1500VA UPS I added to help trouble shoot the problem. I called Apple support and they suggested that the wiring in the room was faulty/not grounded properly. I have since moved, and am still having the same issue. I am not having any performance issues. I’m just wondering if my machine is defective.

While running only Camino and stock system processes, Bresink Hardware monitor says the Power Supply is producing 102 Watts, 12.17 Volts, 8.3 Amps.

Thanks in advance,