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wmjr 12-31-2013 01:49 PM

Galvanic Isolator
I am going to install a galvanic isolator on my 31 Pacific Seacraft. I have read (Maine Sail) that the best place to connect to the AC ground is very close to the shore power inlet. That could make a short run to the isolator since I would install it in the locker aft of the head.

Unfortunately I am having a very difficult time finding access to the the AC connector inside the boat. It looks like it should be easily accessed on the starboard side in the head. Not so.

If there is no access I will have to connect the new portion of the AC ground wire to the existing ground wire at the panel, run 10 feet aft (right back past the hidden AC power inlet ( a few feet from where I want to install the Galvanic Isolator), connect to the new isolator and then run the ground wire right back past the hidden shore power inlet to the panel to complete the connection to the AC ground at the panel.

That makes a total run of 25 or 30 feet going forward, back and forward again instead of a 5 or 6 foot detour loop to the new GI and back.

Has anyone seen an access to the AC shore power inside the boat on a 31? Anyone else installed a galvanic isolator somewhere else?

PSC 31 #28

AlLorman 01-01-2014 10:10 AM

Re: Galvanic Isolator
I just installed one on my Freedom. I unscrewed the 30 amp receptacle from the boat and pulled it free (with wires still attached). I removed the ground wire and butt spliced a long piece of green wire to it. I also attached a new long green wire to the receptacle. I then fed both of the green wires down into a cockpit locker, where I attached them to the isolator.

The main reason to attach an isolator near the AC input is to make sure that you are capturing all of the AC current. If you are sure that the AC runs without interruption straight to the panel, then that is a fine place to install an isolator.

Al Lorman

PSC 31 Ann West (for sale)
Freedom 35 Ab Initio

34crealock 01-01-2014 10:43 AM

Re: Galvanic Isolator
I installed one on a PSC 34. To put it right with the AC inlet I had to remove the entire headliner in the quarter berth. Easy but time consuming.

wmjr 01-01-2014 09:25 PM

Re: Galvanic Isolator
Al (Freedom),

Duh, I never thought of trying to get at it from the outside. Tomorrow I will see if my Pacific Seacraft is set up the same way as your Freedom. Thank You very much.

Al (Coorie Doon),

Yep, looks like same type of thing on the 31 except it is the headliner above a shelf space in the head. I would have to drill out the bungs on the teak trim, remove the screws from the trim and headliner and hope that would let me pull out some kind of shelf inside the space that must contain the shore power inlet. I hate to drill out the bungs and then have to repair and re-varnish but if it works it would make the wiring easy. Sad sad song if it did not give me easy access.

I think I should call Pacific Seacraft. Thumper has always been a tremendous help when I have needed it.

I appreciate the advice. Thanks again,

PSC 31 #28

mondofromredondo 01-02-2014 11:47 AM

Re: Galvanic Isolator

When I purchased my '88 PSC 34 it already had a Galvanic isolator installed in the switch panel box. The isolator has (2) large guage leads leading from (2) seperate attach points on the isolator. One of the leads goes to a buss plate in the panel. The other one appears to be running aft to an undetermined location. I am only able to describe this as I am looking at a photo of my isolator as it sits directly below the 110V area of my panel. Sorry I can't provide anything further but thought this may help a smidge.

wmjr 01-02-2014 07:44 PM

Re: Galvanic Isolator

There is no room in the panel on the '31 but right next to it there is a wet locker that I only use for storage. I guess I could cut a hole to frame it and then just take the existing ground wire from the panel to the isolator, patch in a couple feet and run a wire from the output of the isolator to where I took the input.

Might be the easiest.

PSC 31 #28

mondofromredondo 01-03-2014 10:09 AM

Re: Galvanic Isolator

I am guessing that with the galvanic isolator setup you will be hanging a zinc like anode from a stainless cable that attaches/detaches to something mettalic that is linked into your ships ground which is what I do at least.

In my case I attach usually to a mast shroud turnbuckle. I've made the mistake on a few occassions of setting sail with this still attached and the anode dangling 4' down under the boat and inevitably it'll bang against the hull at some point. Suggest if your annode setup will be anything like yours that you might attache a red ribbon or something bright and dangley to draw your attention to the attached anode to remind you to remove it prior to getting under way.

Best O' Luck

Maine Sail 01-03-2014 10:50 AM

Re: Galvanic Isolator

The GI can be inserted into the green/Earth/grounding wire anywhere between the shore power inlet and the AC panel green/grounding/Earth bus. Just be sure it is before the ships AC/DC safety bond...

svjobeth 01-03-2014 04:58 PM

Re: Galvanic Isolator

Originally Posted by Maine Sail (Post 1268353)

The GI can be inserted into the green/Earth/grounding wire anywhere between the shore power inlet and the AC panel green/grounding/Earth bus. Just be sure it is before the ships AC/DC safety bond...

Exactly -

On Jo Beth, ours is installed near the AC breaker panel, further away from the AC inlet, but closer to the AC ground bus. It's working just fine there.

With the refit we're doing, it will be relocated as we're redoing the DC/AC panel configurations somewhat.

wmjr 01-03-2014 11:27 PM

Re: Galvanic Isolator

The connection from AC to DC has me worried.

I have owned the boat for a long time but did not have much time to learn about the electrical system. I retired recently and now have time to begin tracing wires etc.

Whoever had the boat before me had some good ideas. Over 14 years ago they installed a 1, 2 both switch system (alternator to house, ACR, the works, exactly as you describe and diagram it.

But ... they labeled nothing (except the face of the panel).

Am I best off running a wire from the AC panel to the engine ground bolt for my AC/DC connection or does that risk unequal grounding somewhere?

Thanks for your Compass Marine site. Phenomenal place to learn.

Pacific Seacraft 31 #28

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