I appreciate your input. Why do you say you don't think it could be power factor? Also, if current was finding an alternate path back to the transformer wouldn't that mean I would see less than the difference between the two phases on the neutral? The excess neutral current is always 3amps or more. In the last picture I uploaded it is 8.2amps excess. That seems pretty substantial.One way to go about this is to first consider what assumptions are being made in order for the current in the neutral conductor to be equal to the difference between currents on line conductors L1 and L2. And then determine and list possible ways these assumptions could be violated and cause a different result, such as the excess neutral current you're observing.
Here are some thoughts:
1. The vector sum of the sinusoidal currents through L1, L2, and N is zero.
This means that if you put a clamp meter around the L1, L2, and N you should see zero current.
2.The L1-N and L2-N currents are 180° apart.
Ways the assumptions can be invalid and resulting consequences
Assumption #1 would be invalid if there are any currents that do not flow between the L1, L2, and N conductors on the load side of the clamp, and therefore represent unwanted leakage or “common-mode” current on another path that’s not going through your clamp.
Things that could make this happen are:
a. Paths which allow current to bypass around the clamp meter.
b. External sources of current applied on the load side of the clamp meter.
If assumption #2 is not true then you can get a current on the neutral conductor even though L1 and L2 have equal RMS currents and assumption #1 is true.
But you’ve already verified that the L1-N and L2-N voltages are at 180°. So the only way that their currents could depart significantly from 180° is if the power factors on L1 and L2 were very different. In your situation I think this is very unlikely to be causing the amount of neutral current observed.