I have a MultiPlus 3K installed on my travel trailer (RV). There is a very short 110V shock on the trailer chassis when the use first turns on. After it goes through a brief few second start up period (with the Mains light blinking), the unit "clicks". At this time the camper is energized for a split second, but enough to give you a quick shock. Is there a grounding issue that I should be aware of? Anyone have any ideas why this would be happening? Need more information?