Len wrote:
But what do you think of the varistor/fuse setup? I also want to use
it in the incoming shore connection. Some shore connections are
generator powered. That means there is a risk of the null hanging a
bit loose what may cause v-spikes also. Would this setup protect my
combined inverter charger in your opinion?

Destructive transients are done in microseconds. Fuses take tens or
hundreds of milliseconds just to consider tripping. Varistor life
expectancy is defined by a parameter called joules. And then you must
define the type of transient - longitudinal or transverse. The most
damning part of your theory is no numbers. With numbers, you have far
more to consider. Properly noted is that electronics already have
internal protection. So your only question means you must first define
how bad that generator really is. Again, get numbers - specifications.
Without first defining what you are protecting from, then no one can
provide anything but wild speculation - Rush Limbaugh type response.