Jim
You read it correctly, but the scary part is you are not willing to accept it, while you seem to be fine with the advice offered by the throughly unqualified. If you were to plug a welder or anything other than a thermally protected motor of 15 or less full load amps into the 15amp 240volt receptacle, you are correct in that the breaker should then be changed. If you were worried about your 30 or 40 amp welder overloading the #12 wire, send me a picture when you get it plugged into the 15 amp receptacle, but you have electrical training and already knew that. I am not aware of a any delay breaker and the most correct breaker for this installation is called a high magnetic. It only has a magnetic trip device and no thermal trip device, as the thermal protection is included in the motor itself. This breaker would be a special order for most suppliers and the normal thermal / magnetic that they have in stock will work just fine. I also was not aware that we were using a motor starter. If we don't use a starter there are no heaters to upsize. If you choose him and upsize a heater by as much as 10% you loose 70% of the thermal protection offered by a motor starter.

A motor starter provides two things: 1. thermal protection 2. the ability to turn the motor on and off. If you don't need the thermal protection it is a very expensive switch. That guy must have gotten his electrical training from his second wifes' stepsons' friend that worked the counter for two weeks at an electrical supply house. While this forum is not intended to teach all the requirements for installing a compressor, my last post said if you did not already know what I was saying that, YOU ARE NOT QUALIFIED TO DO YOUR OWN ELECTRICAL WORK!!! Almost all insurance policies have a clause that boils down to this; should your non code compliant electrical work be deemed the cause of the fire or injury, they will not pay any claims against them.This should not be considered a word to the wise, as they don't need it, this is for the stupid ones. Is this the DIY forum????? If you guys want to offer electrical advice you should first go take and pass a master code test. It ain't as easy as it looks. :cheesygri :cheesygri :cheesygri