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Discussion Starter · #1 ·
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?

John
PSC 31 #28
 

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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
Annapolis
 

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Maine Dub
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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.
 

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Discussion Starter · #4 ·
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,

John
PSC 31 #28
 

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Mondofromredondo
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John,

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.
 

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Discussion Starter · #6 ·
Keith,

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.

John
PSC 31 #28
 

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Mondofromredondo
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John,

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
 

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Guys,

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...
 

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Guys,

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.
 

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Discussion Starter · #10 ·
Maine,

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.

John
Pacific Seacraft 31 #28
 

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Recently (3 weeks ago) installed a galvanic isolator on Crazy Fish.

Mounted it outboard on the rear quarterberth bulkhead a short run from the AC plug. Probably above the level of the original headliner but the quarterberth headliner was removed many years ago and never reinstalled.

One of the simpliest installations of devices on the boat.

Marc Hall
Crazy Fish - Maintaining, Upgrading and Sailing a Crealock 37
 

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Discussion Starter · #12 ·
Marc,

Thanks, I ended up putting the Galvanic Isolator in the wet locker aft of the head mounted just below the new charger. With Thumper's help from Pacific Seacraft I found access to the shore power cable very close to the inlet.

Next challenge is to link the AC ground to the DC ground.

John
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PCS 31
 

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Marc,

Thanks, I ended up putting the Galvanic Isolator in the wet locker aft of the head mounted just below the new charger. With Thumper's help from Pacific Seacraft I found access to the shore power cable very close to the inlet.

Next challenge is to link the AC ground to the DC ground.

John
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PCS 31
Just check continuity behind the panel. Put one lead to AC ground and the other to the DC bus... Most boats built in the last 20-30 years are wired with the AC/DC bond, though a few brands were not....
 

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Discussion Starter · #14 ·
"Just check continuity behind the panel. Put one lead to AC ground and the other to the DC bus... "

I checked for continuity from AC ground to DC bus behind the panel. No joy.

Here is my plan:
1. temporary fix - Connect a 10awg green wire from ac ground at panel to dc bus at panel 12 inches away.

2. March to the future - Having read every post about ground(ing) on every site plus every compass marine diagram and picture plus Calder I intend to clean up the battery area by installing positive and negative bus bars with one of them becoming the new dc negative bar and a second bar (connected to that one) to terminate the non-conducting grounding wires and then on to engine ground. No fuses now at battery so that project happens at the same time.

Here is what is stopping me:

A) The all neg to one place law.

There are now two negative wires going to the engine (three if you count the alternator which is a 2G wire from alternator to battery 1 negative post.)

1) One 4G wire from bat 1 to bolt where transmission bolts to engine.
2) One 4G wire from DC neg at panel to second bolt where transmission bolts to engine. These bolts are 4 inches apart. The DC neg wire would be brutally difficult to re-run to the proposed new neg bus bar in battery compartment.

Are two bolts four inches apart on the engine one place or two?

Sorry for the consulting fee worthy length but this stuff has a lot of pitfalls.

John
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