Galvanic Isolator

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obthomas

Guru
Joined
May 16, 2013
Messages
560
Location
USA
Vessel Name
TheVenture
Vessel Make
1985 Bestway Labelle Sundeck 40ft
I just made some shore power changes on my boat and noted that I do not have a galvanic isolator before the green shore wire lands on the green on-board grounding buss. Dutifully I bid on and won a 60 amp Quicksilver fail safe variety of galvanic isolator on Ebay. Meanwhile I was reading up on installation and also noted that one needs to test these things from time especially if they are not the fail-safe or monitored variety. So hold on I am getting to my question.....Since my fail safe galvanic isolator is not monitored and I would like to know if my galvanic isolator is working properly and some diodes are not blown leaving me and some swimmers without protection...... why couldn't I just wire up a receptacle next to and right after my quicksilver galvanic isolator and use one of them there yellow plug-in testers? You know they cost about a dollar and have three lights that tell you if the power to the receptacle is right? :D
 
Greetings,
Mr ob. Couldn't you just check any plug on the boat or do you not have one in close proximity to the isolator?
 
Greetings,
Mr ob. Couldn't you just check any plug on the boat or do you not have one in close proximity to the isolator?


I think you are right ! :facepalm: Guess I was thinking an outlet next to the isolater in the electrical closet and leaving the checker plugged in all the time.
 
I don't think the home outlet/GFCI tester can test the galvanic isolator.

The GFCI monitors and cuts out the leaks between hot or neutral and ground wires. This is what protects you or swimmers in water.

The galvanic isolator or isolating transformer separates shore ground from boat ground and cuts out stray current coming from a faulty shore installation.

Two different things.

FWIW, there are various testing method described if you google for it.
I have not tried any of them ... one more thing to do this spring, ugh ...

Google: http://www.google.com/search?q=galvanic+isolator+test+procedure
 
Last edited:
This is a better solution: from Wikipedia "An isolation transformer is a transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, usually for safety. Isolation transformers provide galvanic isolation and are used to protect against electric shock, to suppress electrical noise in sensitive devices, or to transfer power between two circuits which must not be connected. Isolation transformers block transmission of the DC component in signals from one circuit to the other, but allow AC components in signals to pass. Transformers that have a ratio of 1 to 1 between the primary and secondary windings are often used to protect secondary circuits and individuals from electrical shocks.
 
AFAIK, a galvanic isolator will not protect from electric shocks but will protect the boat from galvanic corrosion.
 
"Failsafe" means the diode (if it fails) will close, therefore the ground is maintained so a 3-light tester will not work for testing.
 

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