Blodgette issue convection oven 208/240 60Hz haveing issue with plug over heating what size breaker should i use 20 or 30amp. Wiring is on a line seprated. What gage wire should i use.

First reset your breaker, then check your wiring in the back of the oven. You may have just a wire loose.

Flip both oven breakers HARD to the "off" position, then back on. If it did not help - you might have a problem with a relay on the control board or a failed bake element.
Grab a flashlight and check the element on the bottom (if you can see it). DO NOT TOUCH THE ELEMENT! If you find any bulging or cracking on the element - it'd out. Before removing the element turn the oven off on the breaker panel.
PS Model number is needed to find the part numbers.

I went online to the Blodgette Company. I went to service request and asked the same question. I recieved an answer via e-mail, the items and part numbers need. I then contacted a local distributor for the items needed.

1) If there is a reset on the electronic panel try that.
2) Set the temperature to 200 and see if works then.
3) Put a baking tin in the oven with a piece of meat in it.
4) Uninstall the Wall Oven and take the back off and check the wiring for the elements and the convection fan.

I need to know the Power rating Example 5Kw or the Ampere Ex. 30A . What is the raring of each oven? The Breaker should be greater than the Ampere of your oven let say 120% greater.

I think the issue you are dealing with is the NEC. National Electric Code. Most callouts for conductors are in reference to your home wiring. Due to voltage drop and heat the NEC always errs on the side of safety. Most structure wiring is covered so you never want issues of heat in conductors. The wires on your oven are only several feet in length and I am sure are sized properly from the manufacturer for their intended purpose.

You must use a three-wire, single-phase A.C.
208Y/120 Volt or 240/120 Volt, 60 hertz
electrical system. If you connect to aluminum
wiring, properly installed connectors approved
for use with aluminum wiring must be used.

That means that you ned a double 40 amp breaker.

Good Luck

It is probably and electrical service issue. If this is a North American unit, it uses two electrical circuits to provide power. You must find and reset the breakers and check that the wiring is operating as intended. Less likely: It could also be a manufacturing defect. DeLonghi uses screw compression connections on some products. Sometimes, they don't work well.

This sounds like a control panel issue, you may have to replace it, about $300.00