Like Ectofix said, there is a bleed of electricity to the ground system somewhere. We are talking Milli-amps here. Finding the source can be a bit daunting. It can be some dust or flour that has some moisture to it. Oil track, The use of a Megger can help if you know how to use one. Other wise a quality ohm meter and individual isolation of elements will work.
To eliminate a bad GFIC, go inside the machine power connection cable and open the ground wire to place a milliamp meter in series of the ground curcuit.. If you see over 5 milliamps, Then you need to find it inside the machine. Less than 5ma means your GFIC is bad.
Great points! I would like to add that a GFCI trips when the cumulative leakage for all the connected appliances goes over the threshold (5ma). If there are other things plugged into the same GFCI the HL200 might just be the “straw that broke the camels back”.
My preferred method for finding leakage current is to use a clamp meter that can read milli-amps and then clamp around the hot wire and the neutral. Any measured milli-amps from this test would be leakage.
I forgot to mention one important point that often is overlooked. That’s where the GFI is at. If close to the load, not a problem. But if it’s a long distance away you can get induced current in the ground wire. I have seen over 300 volts on a support wire for overhead before the telephone company installed ground stakes at every pole. I’ve also seen farm fences with high induced voltages that run parallel to power lines. There are higher value GFI’s available for commercial use. Up to 8 ma.