An ELCI is sort of a whole boat GFCI like that found in homes and boats. A GFCI is required by current electrical codes to protect people in wet areas: bathrooms and kitchens. Usually it is a device built into the first outlet in a series which protects all subsequent outlets.

A ELCI works similarly but is set to trip at higher currents to avoid nuisance trips. But boats are inherently wet and I think the chance of nuisance trips outweighs any safety advantage.

Just make sure that you have GFCIs in your galley and head and forget whole boat ELCIs.

David