Product Selection

Selecting an appropriate Galvanic Isolator is an important but simple process. 

Typical Product Selection

DEI Isolators are typically applied using an industry standard method of matching the device to the steady-state current rating of the shore power service. In order to select the best product for your vessel you must know the size of the shore power service on your boat and choose the Galvanic Isolator accordingly.  

Shore Power Size


Dual 30A


Dual 50A



Recommended DEI
Galvanic Isolator 















Fail-Safe Plus and Fail-Safe MAX

Fail-Safe Plus models meet the requirements of ABYC A-28 for fail-safe galvanic isolators, while the Fail-Safe MAX versions offer even more robust performance. Fail-Safe MAX products have fault current ratings so high, that the ground wire would melt before the product will fail.  The choice between these two models can be made at the customer's discretion.



Alternate Product Selection Method - AC Fault Current

DEI Isolators are typically sized to match the steady-state AC rating of the shore power service, which typically also provides an appropriate associated AC fault rating. If an alternate location is planned or higher fault current is expected, there are other methods available for rating the products. This can include sizing the products based on known fault currents, coordinating with upstream circuit breakers, or coordinating with grounding conductor size and ampacity. Contact DEI if additional information is needed.