


Outlets have ground wire but testing as open ground.
These outlets come off a sub panel on the second floor. All the ones on the main floor show as grounded but all the ones upstairs are showing open ground. What could cause this? Anything I can do to troubleshoot as a home owner?
Attaching pictures of the sub panel main panel. The sub panel comes off the 2 30amp breakers that are switched to off on the main panel.