I use a regular USDM Kill-A-Watt and it works/reads on 220 just fine as long as you dont exceed around 8 amps of current
how do you have it connected to the 220? My PDU has C19 plugs, are you using an adapter to convert C19 to 5-15 and plug the kill-a-watt into it? Pics of how you have it setup would be great. I thought the 5-15 plugs were only 110V, so I'm confused how you are plugging the normal Kill-A-Watt into your 220. thanks