galvanic isolator, which one? 16amp or 32amp

[Srpulpo]

I am not great with electrical but need to put in a GI as recomended by my surveyor. It seems like a 32 would cover it? I have a 30 amp shore cord if that means anything?

[boatpoker]

Originally Posted by Srpulpo

I am not great with electrical but need to put in a GI as recomended by my surveyor. It seems like a 32 would cover it? I have a 30 amp shore cord if that means anything?

It means a lot. Don't know where you found a 32amp isloator, you should have a 30amp unit.

Don't cheap out. ABYC compliance requires a "failsafe" unit like this one.
https://www.promariner.com/en/p/2203...sltr-FAIL-SAFE

[Matt Johnson]

Originally Posted by boatpoker

It means a lot. Don't know where you found a 32amp isloator, you should have a 30amp unit.

Don't cheap out. ABYC compliance requires a "failsafe" unit like this one.
https://www.promariner.com/en/p/2203...sltr-FAIL-SAFE

Europe, Asia, Africa... Anywhere not NA. 32a is sold by all manufacturers for 230v systems.

[Cheyne]

Victron's are 16 amp, 32 amp and 64 amp.

Cheyne

[Srpulpo]

victron has 16, 32 amp GI

[boatpoker]

Originally Posted by Matt Johnson

Europe, Asia, Africa... Anywhere not NA. 32a is sold by all manufacturers for 230v systems.

Is the OP in Europe ?

[GordMay]

Originally Posted by boatpoker

Is the OP in Europe ?

According to his profile:
Location: San Francisco, California
Boat: Passport 40

[wholybee]

Originally Posted by boatpoker

It means a lot. Don't know where you found a 32amp isloator, you should have a 30amp unit.

Don't cheap out. ABYC compliance requires a "failsafe" unit like this one.
https://www.promariner.com/en/p/2203...sltr-FAIL-SAFE

For a 30A circuit, a 32Amp isolator is fine. A 29A or lower isolator would not be.
Yes, get a failsafe unit, or an isolation transformer instead.

[s/v Jedi]

Actually, for a US 30A inlet, a 32A galvanic isolator is even better than a 30A version.

Grab the attachment now that you see it… so you can read it yourself

[Srpulpo]

SF Bay Area USA

[boatpoker]

Originally Posted by s/v Jedi

Actually, for a US 30A inlet, a 32A galvanic isolator is even better than a 30A version.

Where does it say that in A-28 ?

[mvweebles]

This gets a bit technical. ABYC has a spec - A-28 - that requires a GI to 'fail safe' meaning if it fails, it fails in a protected state. I'm not a purist with ABYC, but this one makes a lot of sense.

Whatever size you decide, go with the Promariner Boatpoker cites in #2. They are A-28 compliant. Newmar, a decent company, makes some vague statements of engineering, but in the end, they have not been tested to be ABYC compliant.

[s/v Jedi]

Originally Posted by boatpoker

Where does it say that in A-28 ?

Nowhere. The amperage rating is for maximum amperage, i.e. both a 30A and a 32A isolator can do 1A or 20A but only the 32A one can do 31A. It’s how ratings work.

Originally Posted by mvweebles

This gets a bit technical. ABYC has a spec - A-28 - that requires a GI to 'fail safe' meaning if it fails, it fails in a protected state. I'm not a purist with ABYC, but this one makes a lot of sense.

Whatever size you decide, go with the Promariner Boatpoker cites in #2. They are A-28 compliant. Newmar, a decent company, makes some vague statements of engineering, but in the end, they have not been tested to be ABYC compliant.

This isn’t the whole story, you skip the boldface part of A-28 that explains what failsafe means: it means that when the device fails, your propeller and other underwater metals can be quickly eaten away because the whole isolation protection is lost. A big fail (but when they forgot a RCD type breaker then you do get protection from the ground wire)

For this reason one shouldn’t have these isolators at all and use an isolation transformer instead, which doesn’t have any of these problems, which is why I have it in all the reference diagrams

Edit: I don’t think a failsafe unit is a requirement in A-28. You can also have a monitor with alarm function, which I would prefer as you get alerted not just for personal safety but also it keeps the boat protected.

[wholybee]

Originally Posted by s/v Jedi

Nowhere. The amperage rating is for maximum amperage, i.e. both a 30A and a 32A isolator can do 1A or 20A but only the 32A one can do 31A. It’s how ratings work.

Does this count?

28.7.3 The current rating of the galvanic isolator shall not be less than the rating of the main shore power
disconnect circuit breaker as installed per ABYC E-11, AC & DC Electrical Systems on Boats

[s/v Jedi]

Originally Posted by wholybee

Does this count?

28.7.3 The current rating of the galvanic isolator shall not be less than the rating of the main shore power
disconnect circuit breaker as installed per ABYC E-11, AC & DC Electrical Systems on Boats

I guess… I don’t really see how weird it can get on the forum…

But I believe the 32A came from a Victron unit which doesn’t comply with A-28 so it’s a moot point.