Shorepower line to main breaker

[karista]

I just installed my Galvanic Isolator, which is spliced into the ground wire at the shore power inlet. I found that Catalina used 12 gauge wire from the shore power box to the main 30 amp breaker, at least in my boat (1990). This is clearly not to code or safe as it requires 10 gauge wire. You may want to check your wire to insure its the correct size. I am the original owner so no one has tampered with this wiring and I never checked until now.

[Ron Hill]

In Catalina's defense : There's a placard just under the engine instrument panel.  It states something like "This vessel was met the standards when it was built". 
FYI. the best example of the electrical code changes imposed by the ABCYA is the difference in the electrical between the 1987 and 1988 / subsequent C34s. 
 
In your house you'll find that : 14 gage wire goes to a 15amp breaker
                                           12 gage wire goes to a 20amp breaker
                                           10 gage wire goes to a 30amp breaker 
It's a safety factor if you're drawing over 20 amps. on your 12 gage wire!!   
So take Bernd's advice and upgrade to 10 gage wire so you'll have the protection just in case you ever draw over 20 amps!!