Best overcurrent protection device for Charles isolation tranformer?

[Pau Hana]

You’ll love it.

I hated to read a couple years ago that Charles Industries was discontinuing it’s IsoBoost models, which gave rise to the rumor they were stopping production of all marine isolation transformers. Thank goodness the rumor was incorrect.

I week in- all is well. We’re dockside at Roche Harbor, plugged in with zero issues.

Not having to do the amp dance is a blessing!

Nothing onboard is 220v, so I’m ok without the boost function.

 

[exmaggiedrum]

When you say "stray current" I assume you mean in the dangerous form, which can cause death or injury and not stray current corrosion? If you are referring to electrocution risk, electricity returns to its source; inverters, along with generators and shore power transformers, when the source of power, exhibit this phenomenon. In these cases leakage will not travel through the water because it has no reason to, it's not a path back to the source. This is why an isolation/polarization transformer makes for a safer shore power installation.

Shore power, on the other hand, for all intents and purposes, originates at the transformer in the marina parking lot or head of the dock, and thus leakage will travel through the water to return to that source.

I have yet to encounter a verified case of electric shock drowning (ESD) or in water electrocution from an inverter or genset, if anyone knows of a verified case please share.

Having said all that, inverter/genset and vessel wiring faults can still occur aboard, which can lead to electrocution, just not in water electrocution or ESD, and fire, so an ELCI on the inverter (and genset) output, along with GFCI receptacles, is still a good idea.

Thanks. Your explanation as far as the path through the water back to the source makes sense. I had never heard of inverters making stray current but thought it was worth asking. I have seen where non-marine inverters have created problems at the marina. AC is always protentially a dangerous thing, like you say. I have wired my boat to ABYC guidelines for AC and grounding but I don't have an ELCI breaker on the inverter. When I was working on boats a few years ago they were only on some European boats and not considered important. If I were keeping the boat I would definitely install one as your suggest but will let the new owner make this upgrade.

 

[Steve DAntonio]

I week in- all is well. We’re dockside at Roche Harbor, plugged in with zero issues.

Not having to do the amp dance is a blessing!

Nothing onboard is 220v, so I’m ok without the boost function.

If your shore power is 50 amp, 240 VAC, regardless of whether or not you have 240 VAC gear, the 208/104 issue remains. If you plug into 208, and you have a non-boosting transformer, your receptacles will be supplied with half the dock input voltage,, or 104 VAC.

If your shoe power is 120, 30 or 50 amp, then it is indeed an non-issue.

Glad the transformer is working for you in Roche.