PowerMac G5 won't boot in one location

Question

Here's a strange problem. We have a pair of PowerMac G5's. Second and Third generation. They boot fine from my place of work. But at my new residence, they do not boot at all. I went back and forth between the places 3 times. Yet I can't even get to single user mode (UNIX prompt).
I tried plugging the computers into each grounded circuit in my house. I first tried it with my new 20 amp outlets (20 amp each). I had a qualified electrician come to my house and tell me that the outlets are "clean": well grounded, good voltage (4 volts over "you get what hydro gives you"), etc.
I know that the G5 draws a lot of current when it starts up but according to my electrician, my circuitry should definitely be able to handle that plus a whole lot of other guear.
A G5 iMac works fine. All my PC's work fine. I did discover a dead power supply on one of my routers, but I don't know if it died before or after the move.
I've searched the apple site and web and couldn't find anything on this topic, which is even more baffling. I don't believe in singularities within mass production--I can just assume that anyone who has experienced this has not posted, or applecare might be able to provide an answer.
My next move will be to introduce a UPS, such as the Belkin UPS Line Conditioning And 4 Battery Backup (550VA), e.g.,
http://www.futureshop.ca/catalog/proddetail.asp?logon=&langid=EN&sku_id=0665000F S10054425&catid=10446
Needless to say, I'm completely floored by this problem, and so is our IS/IT staff.
So if this is not a question, it's at least a post "for the record".
Thanks,
Luc

Answer 1

Well, I searched the web all over, and Apple's web site, and I even phoned Apple's tech support who took several minutes to research this: I found no solution to my problem. So I'll describe the problem and the solution. (Maybe a better googler would have found the solution, but Apple couldn't help!)
To recap: I moved to a new, older, house recently. I installed 4 20 amp circuits to handle my equipment (over $1,000 for this). I plugged in my PowerMac dual G5 (second gen) and tried to boot it up. Nothing. Wouldn't even get to the command prompt, though the power light was on. Tried every outlet in the house. I brought this computer back and forth to my workplace, making minor modifications as you would expect for debugging (resetting pram, etc., swapping RAM, etc., etc.). Nothing worked. So I tried a different PowerMac G5 (3rd gen). And this one had the same problem. Bizzaro.
I had the electrician come to my house again and he measured several of the outlets and said they were all clean. All within the specs of Apple. Voltage was a bit high but within normal range. He even measured it during the attempted boot up.
I tried a UPS. It idn't work. I phoned APC, and they told me that they have frequently fixed PowerMac G5 users' problems with their:
APC Model SUA1500: line interactive UPS, pure sine wave, list price = $US 519. So that means my original UPS just wasn't good enough--lucky I pursued that further.
So that would be my solution, assuredly. I won't even bother to buy the thing, cause the price is too high and I don't know how long I'll be staying here. So I've been demoted to an iMac 1.8Ghz. Better than using a G4 anyway.
Dual G5   Mac OS X (10.4.3)   2 GB RAM
Dual G5   Mac OS X (10.4.1)