I have bought a counter top prima super chef roaster, when plugged in it trips the circuit breaker in electric box, any suggestions.

Probably close to 50 things could cause that, but here are a few of the most common: Bare wire in a harness of the oven, causing a short-circuit in the line. Faulty plug on the power cord. Outlet in the wall is damaged. Loose wire in the outlet box, causing a dead short. Bad wire between the outlet box and the main breaker box. Weak breaker, or a breaker that isn't heavy enough to handle the load of the oven. (especially, if you just bought a new oven, it may need a larger breaker to handle start up.) Use a fused multi-meter (voltmeter) to check for these issues, and do not try to fix it if you are not familiar with electrical work. It could cause a fire, or give you a deadly shock.

Check the house circuit breaker for the oven. If 240 isn't present, everything else will work except the heating element. The circuit breaker will have it's handles joined so if one trips they both trip. Unfortunately, this doesn't always work, Meaning one can trip without tripping the other so only 120 volts is supplied to the oven.

In the power panel on your house. There are two circuit breakers with their handles joined.One of these breakers has tripped internally which will stop the heating elements but not the control panel or oven light since they work on 120 volts. Reset the breaker or replace it.

Good Morning Friend,

I understand that you are not receiving power to your Frigidaire oven, model# FEB30T7FC, even though the power is on to your home and the breakers have not been tripped. Please try the following:

1)Be sure the electrical cord is securely connected into the electrical junction box.

2)There is a possibility that the service wiring is not complete.

3)There is also a possibility that there is a short in the cord or plug. Replace the cord or plug.

4)The house fuse has blown or the circuit breaker has tripped immediately following installation. The house fuse may not be fully engaged. Check the fuse and screw or engage circuit breaker securely.

I ask that you please follow up with a comment on the post, at your convenience, to advise if further troubleshooting is needed or if your appliances status has changed successfully. Hope this is helpful.

-Best Regards-
WP

Check the thermal coupler a copper thermometer for your stove after checking all the fuses in stove and circuit breaker box of house to see if any have tripped. Circuit Breakers should have the switches all in a line. Any not in the lie will be tripped. Fuses in your stove are usually in the top part of the stove where the instruments are and fuses screw out and visually are easy to detect if they are blown or not. Remember all ways Unplug what you are working on to prevent shock

It might be that a circuit needs to be reset. Find your circuit breaker box (usually in a garage or a closet); you should be able to see a circuit that is going in a different direction than the rest--it might even be labeled). Push that circuit switch to the opposite direction. Hopefully this will work.

If the fuse or circuit breaker is tripping it is most likely a short circuit in the oven element.

If your oven won't heat at all, the most likely problem is a blown fuse or a burnt out element. Assuming you're not attempting to repair an antique, your oven will have a clock. If it has also stopped working, it's safe to assume the oven is not getting electricity. Check your circuit breaker box and reset the breaker if necessary and see if this fixes the problem. If not, cut power to the oven at the breaker box before going any further. Note that your oven runs on 220 volts. There should be a double switch on the circuit breaker board controlling power to it. If not, there will be two single switches that need to be tripped to cut power to the oven.
Even if you didn't find a blown circuit breaker, the problem could still be a blown fuse. Some older ovens have their own set of fuses located under the range top, in the back of the oven space, or behind the oven. Inspect the fuses and replace any that have blown with one of the same amperage. Your oven might also have a circuit breaker with a reset button on the control console or on top of the oven that needs to be reset.
If you are still confounded, pull the oven away from the wall. If it is a range/oven combo, make sure it is plugged securely into the wall. If it is a stand-alone oven, inspect the wiring in the junction box to make sure everything is tightly connected and the wiring doesn't show any signs of damage.

I'm not familiar with this oven, but it ought to have protection against this kind of exciting burn-out.
This could be a fuse: find it and replace it, or it could be a circuit breaker: look for a reset button.
As I said, I don't know this oven; this attempt to help is based on the general idea that it ought to have some built in protection.