I was right in that I need to disconnect the AC side of my distribution panel somehow, but I didn't realise that I have to avoid having the converter (that transforms 110v shore power to 12v to charge the house battery) connected to 110v inverter power. I've had a look at my setup and this is a simple diagram as it is now:
Link here if the diagram doesn't appear
Shore power comes in to the top of the AC breaker panel and the converter gets its 110v supply from the load side of the GFI breaker. The converter then supplies the DC distribution panel and charges the house battery. Easy.
Here's what I think I need to do to install an inverter to just power the 110v receptacles so we can charge phones, run our kitchen appliances and watch TV:
Link here if the diagram doesn't appear
So, I plan to disconnect the existing shore power line in from the Main breaker and disconnect the converter from the GFI breaker output. I'll have the converter connected directly to shore power so it will only charge the battery and power the DC distribution panel when shore power is live i.e. the converter is isolated from the inverter output.
I'll use an automatic transfer switch with the output going into the Main breaker. This will automatically choose between inverter power and shore power, with shore power winning if they're both live at the same time. Finally, to avoid the A/C, Microwave etc from using inverter power I'll install a triple pole single throw relay on the load side of the A/C, microwave and conv. W/H breakers with the coil triggered by shore power. The relay will be normally open so only when it's energised from shore power will the three circuits close those high power circuits. The receptacle circuits won't have a relay as I want them to be power from the output from the transfer switch and work on either inverter power or shore power.
Is there anything I've missed?
Cheers
Simon