Sundowner Q

[O C Diver]

No, I'm not referring to shore power pedestals. I'm referring to the ELCI breaker that's used as the main AC breaker on every boat built to ABYC standards in the last 10 years, every boat built in Europe for the last 25 years (but called an RCD over there), and a recommended upgrade for every boat that was built without one.

So as a curiosity, if you have an inverter that's tied to the AC grounding system (which on new boats is tied to the bonding system), does the location of the ELCI protect the inverter from converting DC to AC and having a faulty appliance delivering the AC power to the bonding system? This seems a very possible scenario from people anchoring out and swimming off their boat.

Ted

 

[Fleming]

So as a curiosity, if you have an inverter that's tied to the AC grounding system (which on new boats is tied to the bonding system), does the location of the ELCI protect the inverter from converting DC to AC and having a faulty appliance delivering the AC power to the bonding system? This seems a very possible scenario from people anchoring out and swimming off their boat.

Ted

No, The ELCI is only protecting from ground fault in the case of a shore power connection. Because AC sources of power always ground the neutral at the source, in the case of the inverter the AC output is (should be) grounded at the inverter. In the event of a ground fault in an AC appliance powered from the inverter, the ground fault current will return to the inverter and not enter the water.

Ground fault current is only going to enter the water when it is coming from shore power because it's trying to get back to the place it's grounded on shore near the transformer supplying it.

Same with a generator supplying AC power on a boat. If there's a fault in an appliance the fault current will return to the generator through the grounding conductor and not enter the water.

 

[loganmj]

..."These are hand-laid glass hulls correct? Or is there a wooden core? any idea how thick the hull is?"....

I can only speak to the wooden core part... My Dad purchased a Sundowner 30 hull (no deck or topsides) in the mid 80's. I am not sure if it was a liquidation purchase or he got a good deal on it but I remember from a few factory visits you could get those boats uncored or with balsa coring. Ours was uncored and the sides were pretty thin, maybe 1/4", the bottom was thicker but not sure how much, and the keel thicker yet. My vague recollection of a hull with cored sides at the factory was quite thick... 3/4" or so.

 

[della li]

So much confusing misinformation in here so far. The AC ground DOES connect to your bonding system, because both the AC ground and the bonding system connect to the DC negative in one place each which makes them electrically connected. That's the whole reason why you need a galvanic isolator. If you don't connect the AC ground to the DC ground then you don't need a galvanic isolator (the european way, ABYC recommends connecting them for safety reasons).

The OP seems to have some confusion with the anodes in the engine heat exchanger and the boats bonding system, they're unrelated.

The Sundowner 30 has a solid glass bottom but the hull sides and decks are cored. Being a 1986 the odds are 99.9% that it's balsa cored. Bonding systems and whether to have one are unrelated with whether a boat is cored or not.

I'm guessing you bought this boat without a survey, these questions would have all been answered.

Q RE galvanic isolator: the instructions say it should be installed in a vented space, I'm assuming to diffuse heat ? I had intended to mount this in a relatively enclosed space near the power distribution panel--bad idea? Should I extend the ground wires and locate perhaps below deck in the engine compartment, which is directly below the power center? This would mean detouring the incoming shore power ground and connection back to ground bus by a couple feet

 

[Fleming]

Q RE galvanic isolator: the instructions say it should be installed in a vented space, I'm assuming to diffuse heat ? I had intended to mount this in a relatively enclosed space near the power distribution panel--bad idea? Should I extend the ground wires and locate perhaps below deck in the engine compartment, which is directly below the power center? This would mean detouring the incoming shore power ground and connection back to ground bus by a couple feet

I think they are talking about heat, but I don't think they make very much heat. They are usually jammed in tight, hard to reach places. In theory the AC grounding conductor that the GI is wired into should not be carrying any current unless there's a fault, and the DC current on the line that's being stopped is in milliamps so I wouldn't personally worry about the heat. I think the enclosed space near the power distribution panel would be fine.

 

[della li]

I think they are talking about heat, but I don't think they make very much heat. They are usually jammed in tight, hard to reach places. In theory the AC grounding conductor that the GI is wired into should not be carrying any current unless there's a fault, and the DC current on the line that's being stopped is in milliamps so I wouldn't personally worry about the heat. I think the enclosed space near the power distribution panel would be fine.

Thx! So if I need to add wire to make the interface, should I use a 10 gauge shore power cable wire, and just strip out the green wire, or the primary wire that comes in rolls at West Marine--can the latter is be used in the 12v and 120v system?

 

[Fleming]

Thx! So if I need to add wire to make the interface, should I use a 10 gauge shore power cable wire, and just strip out the green wire, or the primary wire that comes in rolls at West Marine--can the latter is be used in the 12v and 120v system?

You would just need marine grade, tinned, stranded 10 gauge green wire.