Thinking out loud here...
When plugging into a pedestal, there is already a circuit breaker at the pedestal. So yours would be redundant? Duplicating effort?
Is 50 amp the right size? If you fire everything up, would it be possible that you'll pull more than 50 amps? If you did, the pedestal would trip anyhow, so maybe 50 amp is just right.
The EMS manufacturer may have a recommendation on where to place the breaker or if it is even necessary.