Galvanic Isolator

[Rocky Lou]

I'm pleased to report that after installation of a GI: Promariner Prosafe Failsafe 60amp Galvanic Isolator, my zincs are holding up much better. My diver reported ~85% still in place vs. 15-20% at the same time last year. It was installed in the forward section of the cave and is hard to access. I find it frustrating that you have to trust that it is working since there are no activity indicators, either remote or on the unit itself. However, zincs don't lie.

 

[BB marine]

You can test the Galvanic Isolator to confirm it is functioning per design. This is a good practice to do during annual maintenance inspections. The Older style Galvanic isolators when failed the safety ground would open. This caused a dangerous safety concern. The hull and shaft anodes were still protected because the ground was disrupted between shore power and the boat electrical system. The ABYC found this to be a safety hazard and now recommends that all galvanic isolators be fail safe closed. Meaning if the diodes fail the ground circuit is fully connected and the anode protection is gone. This is not good for the anodes but is much safer for the boat owner and guest.

The old style galvanic isolator should be tested often and when suspected to be failed replaced immediately. The new style should also be tested to confirm that it is functioning and protecting the anodes to extend the anodes service life.

The testing is done the same with either type of galvanic isolator. This isolator has diodes that will block low voltage DC current. The testing is simple if you have a multimeter that has a diode setting. Most VOA meters have this setting.

Testing:

UNPLUG YOUR VESSEL FROM AC POWER !! Remove both green wires from the GI and connect your VOA leads to the studs. Red on one stud Black on the other.

If the diodes are working you should see a reading of .7 to 1.0 V.

Now reverse the VOA leads connected to the galvanic isolator studs.

If the diodes are working you should see a reading of .7 to 1.0 V.

If you have these readings your Galvanic isolator is functioning properly.

(New Style) If you get no reading .000 or OL (open lead) in either direction the galvanic isolator is damaged and should be replaced if you want to protect the anodes.

(Old style) You must replace the isolator to maintain an active safety ground on board.

You don't have to trust that it is working. You can confirm it is working by doing this periodical test. It takes less than a minute to test if the isolator is installed in an accessible location.

 

[briandunnington]

I'm pleased to report that after installation of a GI: Promariner Prosafe Failsafe 60amp Galvanic Isolator, my zincs are holding up much better. My diver reported ~85% still in place vs. 15-20% at the same time last year. It was installed in the forward section of the cave and is hard to access. I find it frustrating that you have to trust that it is working since there are no activity indicators, either remote or on the unit itself. However, zincs don't lie.

Adding a galvanic isolator is on my to-do list for this season as well. As others have done, I will probably combine it with replacing my shore power connector with a Smart Plug since I will be working in that area anyway.

Good to hear that it had such a good effect on your anode life!

 

[Rocky Lou]

Thanks Brian, my Promariner has 'failsafe' in it's brand name, so they clearly want to point that out. It's good to know they prioritized people over anodes.

Checking annually will work. It's accessible but, with some effort and I'm spoiled in thinking electronics can be checked either remotely or on an app these days.

Given the results I saw and if you are in a hot harbor like mine, I'd consider a GI to be essential.