How to Safely Use a 15A Limit Switch to Control 240V 50A Glass Annealer Oven?

Greetings; Not sure this is the right forum aas I am not a electrical engineer but a Glass Artist. Recently built a annealing oven (just a large electric oven) where temperature can reach 1000 degrees. I* want to add a safety factor, limit switches that turn of the exposed elements when the front doors of the oven are open.
The voltage to the oven is 240 volts with 50amps. The problem is that while most limit switches (want to use a horizontal) such as Omron ZE-N-2S-NOS are rated to 480 volts they are only reach 15 amps.
Question how do I maintain the voltage but lower the amps to 15 amps ( or do I need to worry about exceeding the 15 amps) so I can connect the limit switch to shut off power when a door is open.
Simple and cheap is best as I am a poor artist
Thanks

Why do you need a safety factor, if the thermal mass of the whole system is significant then temperature will remain high when the door is open. If it hasn't been on for long then no matter. If the elements are electrically unsafe, in other words the elements are bare and therefore electrically alive, then I would hazard a guess that the design needs to be reconsidered, a safety switch may not be enough.
You should never exceed the maximum rated contact current, if the contacts weld there goes your safety switch. There is an overload capacity built into many relay contacts but that is for transient inductive loads only.
If you have multiple elements then you could place lower current relays or contactors on separate elements, splitting the current and allowing the use of lower contact rated devices. Contactors are usually three phase, at 50 amps I assume that you are using 3 phases, and splitting the elements into three groups. That means 17A on each phase, which eases the contact rating requirement.
Was the wiring checked over by a registered electrician?
Without more details, I would prefer not to say too much more, since the device may well not meet fire and electrical safety requirements.
Cheers,
Richard

Richard gave you a good start. Basically, you don't want to run the entire heater load current through the limit switches. You should have some type of contactor or SSR actually switching the load, and the limit switches should be in series with the control circuit not the load. If you don't have a complete and comfortable understanding of the principles, I'd suggest contacting a licensed electrician for help.