When you say running off your shop. Is that circuit a 20 or 30 amp circuit? How long is the complete length of the circuit from the breaker to the trailer?
First thing is to test the voltage at the trailer. If the above conditions are substandard you are running low voltage and thus high current. Breakers are designed to trip at 80% of rated load. It could be a weak,aged, breaker.
Determine the electrical situation before going further.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles