galvanic isolator, which one? 16amp or 32amp

[Baronkrak]

Originally Posted by s/v Jedi

To be complete:

.......

[twofingerpoi]

https://www.promariner.com/en/p/2203...sltr-FAIL-SAFE

I have the FS-60 which is the proper size since I have dual 30A shore power.

This is perhaps the only vendor on the market that is currently ABYC certified.

It's recommended to mount this as close to the shore power connectors as practical, and of course high enough to avoid water. Mine is mounted in the lazarette aft bulkhead about six inches from the shore power.

[YANDINA]

Well actually, you only need a single 30 amp rating for dual 30 amp service.
If one leg neutral failed and the ground carried the full current that would require the 30 amp capacity.
If the second leg also shorted to ground instead of neutral, current in the second leg would be out of phase with the first leg so its current would SUBTRACT from the first.
If both legs were at 30 amp maximum capacity and both using the ground instead of the neutral there would be no ground current.

[kubota]

hey Jedi,


assume you are specifying a modern toroidal isolation transformer.
the old iron common linear core beasts you find around marine stores
have problems of their own.

worth noting the difference.

[s/v Jedi]

Originally Posted by kubota

hey Jedi,

assume you are specifying a modern toroidal isolation transformer.
the old iron common linear core beasts you find around marine stores
have problems of their own.

worth noting the difference.

Correct, I take the Victron model as the norm.

[Icarus]

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 depends on the W you draw...
Let's say a hot water heater draws 2000W
2000W÷230V= 8.6A
A 60A battery charger draws about 1000W =~5A max
Who knows what else you are likely to plug in all at the same time?
I go for the 30A

[Jlp0217]

Originally Posted by YANDINA

Well actually, you only need a single 30 amp rating for dual 30 amp service.
If one leg neutral failed and the ground carried the full current that would require the 30 amp capacity.
If the second leg also shorted to ground instead of neutral, current in the second leg would be out of phase with the first leg so its current would SUBTRACT from the first.
If both legs were at 30 amp maximum capacity and both using the ground instead of the neutral there would be no ground current.

You're assuming they ae splitting a 50-250 service, if connected to 2 30 amp services, it could likely be the same phase on both, thus 60A.

[MV Caroline]

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?

You are better off just getting an Isolation Transformer. They are pretty reasonable for a thirty amp 120vac system and in my case I installed a multi volt (120/240 vac) 25kw uptick Isolation transformer that provides the proper voltage and phase always. It has meant that there is almost no electrolytic action, zincs last years now instead of months.