My panel has been protected by a 50 amp fuse for years. My inverter is protected off the 150 amp breaker along with the windlass and hf radioand 12 volt dc panel. what I am replacing is the battery selector switch that hasn't had separate wires from both battery banks for years so no worries about any fried diodes The engine alternators are protected separate from the 12 volt dc panel. I am protecting the 12 volt panel with lighting and electronic loads with the 50 amp breaker located at the 12 volt panel.