A 30A Galvanic Isolator WARNING: The galvanic isolator used in this article does not meet the current safety standards. To meet the current safety standards you would need a "Fail Safe" unit that has been tested to the ABYC Fail
While researching this topic, I learned that the ABYC regulations changed a while back regarding galvanic isolators. The change now requires the failure mode to be a short circuit as opposed to the often older failure mode of an open circuit. That means that if there is a failure in newer isolators, a direct connection to shore ground would be maintained whereas in the past, a failure could mean the loss of shore ground, a much more serious electrical condition. In many cases, you might not know that the ground is open.
With the new failure mode specification, it may be prudent to check the isolator routinely since a failure may not be obvious.
Here is an excerpt from a BoatUS article on the subject
The newest designs incorporate technology that can identify these units as "fail safe." Simply put, this designation ensures that even after something as significant as a lightning strike, the galvanic isolator will maintain continuity of the safety ground on board your boat. It may not continue to protect your underwater metals, but the safety ground will be intact, one reason why a galvanic isolator should be regularly checked for proper function.