I have checked all that I know and simplified my testing down to a 20 amp breaker connected to a single 20 amp outlet. Both are new. I show 110 power but still will not power anything. I then put breaker and outlet to another panel to verify they are both good and test fine. This is a new breaker box installed to power my greenhouse operations. I'm stumped as to how to proceed from here. Any direction would be greatly appreciated! Thanks in advance
Usually this is caused by a bad connection. With no current, you show full voltage (we've been on 120/240 for a few decades now, might want to update your 110/220 thinking) but when you actually try to power a load, the high resistance in the bad connection drops the voltage so the load gets very little voltage.
So, check the connections. If you can check voltage while under load (easiest might be a plug-through meter) you would see it drop when a load is connected past the bad connection, and not drop when it's measured before the bad connection.
If you self-installed and did not use a torque controlled driver, get a torque controlled driver and check the panel labeling for proper torques for each type/size of connection (with the power off, of course.)
If the breaker and outlet work fine in another panel, the bad connection would appear to be in the connections to this panel. If the 240V loads are working and the test 120V load is not, then that points to the neutral connection as being most suspect.