It will be bigger than you may need it if you size it to the breaker.
You could size it to the KW of the oven.
I am guessing you want 208 to become 240?
Using the 60 amp breaker and boosting 28 volts I come up with a 10 to 12 kVA transformer.
I got that from this chart.
http://www.transformeronline.com/files/buck-sizingtables1.pdf [This message has been edited by iwire (edited 04-12-2005).]
