Originally Posted by twinboat
Did you check for breakers off in the main panel.
Often they use 2 breakers to power the device. If one is off, it does work correctly.
When I was doing my Hughes Autoformer install a week ago I started by turning off all of the breakers before I started. Then when I powered everything back up and was going to test things out I was at first on a 20amp 120V outlet. I decided to see which of my breakers powered the panel as part of confirming that the RV thought my wiring was correct.
I was turning on a single breaker at a time - and turning off the previous one. When I had breaker 2 (water heater line 2) I noticed that the panel told me I had 50amps service. I assume this is because L1 an L2 were different. As I moved through the breakers I got the same result with breaker 8 (engine block heater).
When both breaker 2 and 8 were on it correctly read 30amp service (it cannot tell 20 vs 30). I remembered this thread and just wanted to add in the breaker pair that worked for me in case it helps others in the future.