Had an ozone generator, from China, which failed to work in multiple outlets in a particular 28 stall barn, where fans, lights, portable radios all worked seemingly just fine. The machine would work elsewhere in other locations. There was a voltage drop/ faulty ground wire to the barn that tripped off the sensor in the ozone generator, and the voltage drop didn’t affect ‘simple’ electrical devices. The electrician was surprised that there was a problem, said it could have been a disaster fire in a rain storm. Discovered after a real electrician checked out my complaints to the farm owner after the farm manager’s inadequate repairs. .
FYI, electrical faults and live horses don’t coexist.