Burned ground wire on inverter

[toddster8]

Well this is somewhat timely. I just checked my brand new Renogy 2000 Watt inverter, still sitting on the work bench, and there is continuity internally between the AC ground and DC negative.

[sailingunity]

Originally Posted by sailorchic34

I will note that I agree with TransmitterDan and I feel that connecting the AC ground to the boats DC ground can create problems. ABYC is a good code, but it assumes everything will always be perfect. On a boat that is almost never the case. So I do not have AC and DC ground connected on my boat. But that's just me.

So what I'm hearing is that if we are connected to shore power, the AC and DC ground should be connected, but if on inveter then no?

[toddster8]

There are enough poles on the (manual) transfer switch to disconnect the inverter ground whenever shore power is on. Seems easy. I wonder how this works in the more expensive charger/inverters with automatic transfer?

[sailingunity]

I better call Victron and see what they say.

[sailorchic34]

Originally Posted by sailingunity

So what I'm hearing is that if we are connected to shore power, the AC and DC ground should be connected, but if on inveter then no?

I would say never run the inverter if your on shore power. But if you must, say with a 220v EU boat in a US marine, either install a much larger ground wire from inverter to ground or, disconnect the ground wire to the inverter. Pretty sure your getting some harmonic imbalance between shore power phase and inverter.


I will note that back in 1990 we did install larger ground wires in PC data centers. That does "solve" the issue, sort of. I think the newer NEC addresses this. But it's been a while since I read it.

[a64pilot]

Originally Posted by GordMay

Indeed.
Which the transfer switch (should) accomplish.

What transfer switch?
I believe we are confusing neutral again, my Inverter has an option of bonding the neutral with the ground I believe when the inverter is functioning.

Besides I’m unaware of specific “Marine” inverters, my Magnum MS 2812 for instance is very often used for house solar installations, so is it a “Marine” inverter? Is my Outback 80 a Marine solar controller? I know my Canadian Solar panels are not Marine solar panels.

I guess my point is that often the title Marine is misrepresented to dictate a higher price, like Marine batteries, I don’t think my Lifeline batteries are Marine either.

So the name marine doesn’t necessarily mean anything. West Marine is full of Marine batteries and other not necessarily quality products with Marine in the title.

See attached screen shot, read where it says ensuring a safe ground

I am not, nor do I pretend to be a Marine electrician, I was licensed for residential work, but a boat is a whole different thing than a house.

[sailorchic34]

Originally Posted by toddster8

Well this is somewhat timely. I just checked my brand new Renogy 2000 Watt inverter, still sitting on the work bench, and there is continuity internally between the AC ground and DC negative.

That would be correct. But check if either hot leg on inverter output has continuity to dc negative. THAT is the issue.

[wingless]

The OEM wiring on my 2000 380DA Sea Ray, w/ factory shore power and factory generator has been working fine.

They use a galvanic isolator between the green ground wire on each 30A shore power inlet and the boat's green ground system. All of the green ground wires on the boat are connected to this system.

My boat has a Guest Dynaplate sintered bronze bonding plate attached to the hull exterior, connected to the green bonding wires.

On my boat, both engines have a large ground stud. On each stud I have thick black battery negative wires and thick green bonding wires. These are the only locations where battery negative and green bonding wires are connected together.

My small inverter is used for additional receptacles, for television power and for convenience outlets around the boat, used for phone and laptop chargers. The original AC receptacles remain wired to the main circuit panel, powered by shore power or generator power.

[a64pilot]

Your saying your shorepower ground is connected to your external plate in the water?
You sure? Maybe they just used green wire to ground the boats metals?

[boatpoker]

Originally Posted by a64pilot

What transfer switch?
I believe we are confusing neutral again, my Inverter has an option of bonding the neutral with the ground I believe when the inverter is functioning.

Besides I’m unaware of specific “Marine” inverters, my Magnum MS 2812 for instance is very often used for house solar installations, so is it a “Marine” inverter? Is my Outback 80 a Marine solar controller? I know my Canadian Solar panels are not Marine solar panels.

I guess my point is that often the title Marine is misrepresented to dictate a higher price, like Marine batteries, I don’t think my Lifeline batteries are Marine either.

So the name marine doesn’t necessarily mean anything. West Marine is full of Marine batteries and other not necessarily quality products with Marine in the title.

See attached screen shot, read where it says ensuring a safe ground

I am not, nor do I pretend to be a Marine electrician, I was licensed for residential work, but a boat is a whole different thing than a house.
Attachment 196965
Attachment 196966

Marine inverters are different and ABYC requires they meet UL and SAE standards not required of non-marine units. None of the non-marine units has the auto neutral switching.

PM me an email address and I'll send you a copy of the standard.

[a64pilot]

I understand the requirements, but just as a reference the Magnum meets those standards, and isn’t to my knowledge advertised as a “marine” inverter, but it may be.
But I bet I can find Marine labeled inverters that don’t meet the ABYC standards, which if I understand correctly aren’t requirements, but are a standard, and often a good idea.
I guess I’m saying that you need to either educate yourself or hire a Marine electrician, and not go by labels.

[wingless]

Originally Posted by wingless

They use a galvanic isolator between the green ground wire on each 30A shore power inlet and the boat's green ground system. All of the green ground wires on the boat are connected to this system.

My boat has a Guest Dynaplate sintered bronze bonding plate attached to the hull exterior, connected to the green bonding wires.

On my boat, both engines have a large ground stud. On each stud I have thick black battery negative wires and thick green bonding wires. These are the only locations where battery negative and green bonding wires are connected together.

Originally Posted by a64pilot

Your saying your shorepower ground is connected to your external plate in the water?
You sure? Maybe they just used green wire to ground the boats metals?

Yes, you are correct. My error, sorry for creating confusion.

Different green wires. One for shore power Earth ground, receptacle to galvanic isolator, then to boat AC wiring. Separate green wire for underwater metal bonding, to hull zinc and to sintered bronze hull plate.

One of those is connected to battery negative on each of the engine blocks.

[transmitterdan]

It sure seems as if Magnum promotes their products as designed for the marine market segment.

https://www.magnum-dimensions.com/si...glepgs-web.pdf

[roland stockham]

Originally Posted by boatpoker

The DC negative and AC ground should always be bonded on the vessel
(as per ABYC).

I believe you may be thinking of the AC ground and AC neutral which should only be bonded at the power source whether generator, inverter or shore power.

I have never understood why ABYC do this. European regs say the opposite that AC ground should be connected to seawater and DC ground seperate and left floating. The issue with connecting grounds is that it is often don by connecting both grounds to a seacock bolt or similar. If the connection comes adrift leaving AC and DC connected to each other but no to seawater then every case and all DC equipment will potentialy at hot wire volts.

[roland stockham]

I am wondering if you have a working RCD. It should have tripped if you have a significant current flowing to earth. If the RCD is fitted and working my guess would be a loose connection on the DC+ cause a short to the casing nd then earth until the ground wire acted as a fuse. In that case where is the main batt fuse and why did it not blow? Sound like you need to check the earths and fussing/RCD's