What I have done on my boat is to hard wire the inverter to a switch.
The switch switches the 110V plugs on the boat to either the inverter
or the shore power. The switch has to be break-before- make. It also
switches both the neutral and the hot wire. So there is no chance of
ever connectiong the inverter to the shore power. So if I want to use
the micro wave, coffee maker, TV,VCR, power tools, toaster etc while I
am anchored out, I have to switch the deep discharge house batteries
to both.( I have a separate starter battery for the engine, so there is
no danger to drain the batteries so that I can't start the engine).
Then I have to switch the inverter on, and then I have to switch the
selector switch to "inverter". When I am on shore power, I make sure
the inverter is off and the selectro switch is to "shore". This system
has worked great, and I feel it is safe, but it may be too complicated
for some.
BTW to recharge the house batteries after heavy use on the weekend, I
have a parrallel switch to chrge the house batteries from the engine
and I ahve solar cells that recharge the batteries while I am away
during the week.

Let me voice an opinion: this is a very abreviated description of what
I have, if you don't understand this, then you should leave this to an
electrician. It is too dangerous to fool around with 110V on a boat.
Rolf