Replacing magnetek 6300 with inverter/charger

DrewE wrote:
For a transfer switch, the ground line should not be switched. Only switch the hot(s) and neutral.

Technically that is correct.

However, in reality, many cheapo inverters may not appreciate having the RV wiring with the equipment ground connected and requires a "floating ground" AND a "floating neutral". So basically isolating the ground via a switched connection may actually be needed in order to get some inverters to work properly since they were not designed to be wired into an electrical "system".

Have to understand that in a RV even though the breaker panel maintains separation between safety ground and neutral, it DOES connect the safety ground to the trailer frame AND that means the 12V battery negative terminal is at the same potential.. Some inverters may internally bond the safety ground, neutral and battery negative ground and may not like that when you plug the entire RV into the inverter and may refuse to work or even go up in smoke..

The reason for that?

Has to do with the design of the inverters high voltage chopper section combined with a "H bridge output" which may depend on a floating neutral and safety ground and with those you cannot tie either 120V output terminals to the same potential as the 12V battery negative terminal without causing damage. Otherwise known as a "transformerless" inverter..

Simplified Circuit looks like this..


You can read up on transformerless inverter theory HERE