Not sure what happened!

[tiltrider1]

Wednesday I stepped on the boat and no power. My ELCI breaker had tripped and my inverter had a fault code. Reset the inverter and all seemed to work fine. Reset the ELCI and 5 seconds later it tripped. Turned every circuit breaker off and then reset the ELCI, 5 seconds and it tripped. I have a switch that bypasses the inverter, bypassed the inverter and reset the ELCI. ELCI held, until I threw the first breaker and then it tripped. Reset, tried different breakers same result, ELCI tripped. Desperation, disconnected every neutral on the neutral bus, reset the ELCI. I then jumped each neutral, one at a time. Got to the refrigerator and the ELIC tripped. Unplugged the refrigerator, reset the ELCI, turned on all the breakers and all was well. Examined the fridge, the compressor had a catastrophic neutral/ground failure which is why the ELIC was upset. Then i turned off the inverter bypass switch, this tripped the ELIC.

Today I tested every ac wire for continuity. There is no continuity between the neutral and ground wires. I did find some continuity between positive and ground (extremely high resistance). I traced this down to some corrosion on an outdoor outlet. Now I have no continuity between positive/ground or neutral/ground. A new refrigerator has been installed and the ELCI is happy until I try to add the inverter. The inverter is working fine except it trips the ECLI. The inverter and ELCI have worked together for 3 years until now.

So, did the inverter kill the fridge, did the fridge kill the inverter, did something else kill them both? Do I buy a new inverter or is there a test i’ve Missed. The inverter is showing some resistance between ground and neutral but since I can only test it disconnect from shore power I don’t know if that’s normal.

 

[GregBrannon]

Thanks for the topic and your thorough description of what you've done to troubleshoot. I regret that I can't help but thankful that I'm likely to learn something.

 

[twistedtree]

What resistance are you measuring between neutral and ground on the inverter? It may be enough to trip the ELCI.

 

[O C Diver]

Check the grounding of the inverter and whether it's tied to the hull bonding system.

Ted

 

[Aquabelle]

Wednesday I stepped on the boat and no power. My ELCI breaker had tripped and my inverter had a fault code. Reset the inverter and all seemed to work fine. Reset the ELCI and 5 seconds later it tripped. Turned every circuit breaker off and then reset the ELCI, 5 seconds and it tripped. I have a switch that bypasses the inverter, bypassed the inverter and reset the ELCI. ELCI held, until I threw the first breaker and then it tripped. Reset, tried different breakers same result, ELCI tripped. Desperation, disconnected every neutral on the neutral bus, reset the ELCI. I then jumped each neutral, one at a time. Got to the refrigerator and the ELIC tripped. Unplugged the refrigerator, reset the ELCI, turned on all the breakers and all was well. Examined the fridge, the compressor had a catastrophic neutral/ground failure which is why the ELIC was upset. Then i turned off the inverter bypass switch, this tripped the ELIC.

Today I tested every ac wire for continuity. There is no continuity between the neutral and ground wires. I did find some continuity between positive and ground (extremely high resistance). I traced this down to some corrosion on an outdoor outlet. Now I have no continuity between positive/ground or neutral/ground. A new refrigerator has been installed and the ELCI is happy until I try to add the inverter. The inverter is working fine except it trips the ECLI. The inverter and ELCI have worked together for 3 years until now.

So, did the inverter kill the fridge, did the fridge kill the inverter, did something else kill them both? Do I buy a new inverter or is there a test i’ve Missed. The inverter is showing some resistance between ground and neutral but since I can only test it disconnect from shore power I don’t know if that’s normal.

The ELCI itself could now be faulty, tripping too easily.

 

[Maerin]

You might also confirm that all the neutral connections for circuits powered by the inverter are connected to a buss that connects to the inverter's output neutral. If any are commingled, it can easily cause an ELCI trip. No issues whatever on a non-ELCI connection. Don't overlook pilot lamp neutrals, they count, too. A pilot LED for a 120V circuit powered by the inverter will function regardless of which neutral it's connected to. They only draw a couple of mils, but it's cumulative. A handful of LED's with crossed neutrals can be enough to hit the ELCI threshold. Some inverters are slow on the draw when they transfer the neutral-ground bond, my Magnum sometimes trips an ELCI when applying shore power and that relay is energized. Not always, it seems to depend on the ELCI, but it's a potential contributor. I turn off the inverter via the remote panel before connecting, that seems to help.

Not sure if it's relevant since it appears your ELCI is on board, but I've found that when connecting to an ELCI it helps to start with all breakers "OFF" and bring them online incrementally.

 

[sdowney717]

I would suspect the inverter is starting to leak current somewhere inside its circuits. The mosfets in those things run on the ragged edge. Or might be a soldering fault, some component is leaking current to ground, since its ac is turning off the ELCI, must be leaking on the AC side of the inverter, even into the DC side of things.

Maybe you can test your inverter on a GFCI circuit isolated from the rest of the boat wiring.
Ground and neutral are joined in a FSW marine inverter usually, but not in a MSW inverter. When off I would think the neutral ground bond should read zero ohms, and you say you have resistance..some use an internal relay, these things are done differently by different companies. So maybe something going on with the switch over, whatever you have, I dont know how its done in your setup..how you have it wired into your boat.

Inverter is like any other AC power source, both neutral and hot must be disconnected together, when not in use.

 

[sdowney717]

Another thing, the cheaper MSW inverters, you can not ground the neutral or the inverter gets damaged.
They put power out on both neutral and hot wires at half the voltage so about 60 vac on neutral and 60vac on hot, you had a serious neutral to ground short, so maybe it fried it, if thats the type you got.

Examined the fridge, the compressor had a catastrophic neutral/ground failure which is why the ELIC was upset. Then i turned off the inverter bypass switch, this tripped the ELIC.

I have a msw 3000 watt inverter wired into my boats AC system and so far its been ok, but I do worry about the neutral ground short issue.
AFAIK, these type inverters measure overloads between hot and neutral and shutdown safely, but the neutral-ground short seems to be a problem at least in the manuals they talk about it.

 

[IRENE]

I will be watching and (hopefully) absorbing closely.

We tripped the ELCI at the newly-installed Friday Harbor G dock.

My electrician found continuity between neutral and ground in two circuits; a Webasto DBW 2010 furnace, and the main exhaust shroud blower. Coincidentally, both of those things have 12VDC and 110VAC parts. The Webasto is 12 VDC but the blowers are 110VAC, and the shroud blower is controlled via relay to the main engine ignition (hope I got that right). Unfortunately, he didn’t want to continue the diagnosis and finish the job. Furthermore, the wires on my multimeter know more about AC electricity than I do.

I have received a recommendation for a suitable electrician by Sunchaser, but have not had an opportunity to align that electrician and the location of the boat, yet.

 

[SteveK]

The inverter bonds neutral & ground once the shore power is removed and disconnects when shore power is applied.
I am going to suggest that the inverter is not disconnecting the neutral/ground bond and thus your ELCI trips.
Test out by disconnecting the inverter ground feed to the bus bar.

 

[tiltrider1]

More information. There is no continuity between neutral/ground or positive/ground in any of the boats wiring, including the wires to the inverter. This is supported by a properly functioning ECLI breaker and multimeter testing.

The inverter which is disconnected from both the DC source and the AC source, shows no continuity between neutral and ground but shows near short level of continuity between positive and ground. This I suspect is my issue but I don’t know if this is a valid test as I don’t know what would be expected from an inverter that has neither DC nor AC connected to it. I could buy a new $2,000 inverter and try it but i’ll Feel real dumb if that doesn’t solve the problem.

 

[Comodave]

When you say positive and ground do you mean between hot a/c and ground. In a/c there isn’t a positive. There is a positive in dc. It could be confusing.

 

[tiltrider1]

When you say positive and ground do you mean between hot a/c and ground. In a/c there isn’t a positive. There is a positive in dc. It could be confusing.

You are correct, I mean hot a/c.

 

[SteveK]

More information. There is no continuity between neutral/ground or positive/ground in any of the boats wiring, including the wires to the inverter. This is supported by a properly functioning ECLI breaker and multimeter testing.

The inverter which is disconnected from both the DC source and the AC source, shows no continuity between neutral and ground but shows near short level of continuity between positive and ground. This I suspect is my issue but I don’t know if this is a valid test as I don’t know what would be expected from an inverter that has neither DC nor AC connected to it. I could buy a new $2,000 inverter and try it but i’ll Feel real dumb if that doesn’t solve the problem.

you need to check inverter in inverter mode trying to supply power. That is when ground and neutral are supposed to be bonded.
When AC shore power is applied to inverter it is supposed to release that bond. It will be the AC from inverter to load that should be bonded when in inverter mode only.
With the GFI doing its job it makes it difficult to run tests. Can't remember if you tried all load off and turn on Shore AC to inverter putting it into charging mode and does it still trip GFI.

 

[Comodave]

I recall some people having a timing issue with some inverters that didn’t break the neutral and ground connection in time to stop the ELCI from tripping.

 

[SteveK]

I recall some people having a timing issue with some inverters that didn’t break the neutral and ground connection in time to stop the ELCI from tripping.

agree, but if working right should reset by the time the breaker is turned back on?
Also some boats had negative and AC ground bonded. He says there is a leak from hot to ground could be enough to trip GFI / ELCI.

 

[Comodave]

Yes a leak from hot to ground can easily trip it. If they are individual breakers for each slip they are 30 mAmps. If they do a whole dock they are 100 mAmp but you are sharing that 100 mAmps with everyone on the dock.

 

[Comodave]

Also, since you have a couple of issues going on, you may have had a power hit that damaged the inverter and the refer. Maybe it damaged the inverters timing circuit so it isn’t switching in time.

 

[tiltrider1]

The ELCI breaker is on the boat so not a dock issue. I have no idea how you would do a continuity test on a powered up inverter. I am hopping the inverter is damaged as that would answer all the questions as to why it used to work and now it doesn’t. My amp clamp is one digit short of giving me a useful answer on current loss.

Since no one else on the dock has issues and since the pedestal breaker was not tripped i’m Thinking either the fridge or the inverter pulled a murder suicide on me.

 

[Comodave]

Ok, that sounds like what happened.

 

[tiltrider1]

Even with all loads off the inverter trips the ELCI.

 

[STB]

Any chance that when you disconnected one of the neutral wires you connected it to the the wrong bus?

What I am concerned about is that the inverter's neutral bus should be separate from the regular neutral bus. And, if it wasn't earlier blowing the ELCI -- they were.

But, since you had the neutral buses apart to debug, in putting them back together, the two neutral buses (shore and invertable) could have gotten tied together. Should this have happened, there is effectively only one neutral bus.

Since the inverter starts out tying neutral and ground together and only breaks this connection once it detects shore power, this could tie the two neutral buses (acting as as single neutral bus) to ground. This in turn could pop the ELCI.

 

[tiltrider1]

The boat is set up with 3 neutral buses. Bus 1 is line one non inverter neutrals. Bus 2 is line one post inverter neutrals. Bus 3 is line 2 neutrals. Buses have separation so you can’t mix things up. Neutral to inverter and from inverter have been verified by checking continuity. At this point we know it is not an issue of wiring. We know it’s the inverter. We just don’t know what the inverter is doing differently. The inverter continues to work as a battery charger and an inverter, however it now trips the ECLI when it never did before. In The mean time I have removed the inverter from the system. I’m waiting on input from the manufacturer on what might have failed to cause this issue.

 

[Gaylord Ballard]

I have seen these break with as little as 5 milliamp deviation. Take VOLTAGE readings between all points black and white. My guess is that you will end up changing out some equipment. Sometimes the electronics simply can't endure the deviations.

 

[Wayne]

Hi, Sounds to me like a shorted capacitor in the inverter. Easy to check.

 

[twistedtree]

you need to check inverter in inverter mode trying to supply power. That is when ground and neutral are supposed to be bonded.
When AC shore power is applied to inverter it is supposed to release that bond. It will be the AC from inverter to load that should be bonded when in inverter mode only.
With the GFI doing its job it makes it difficult to run tests. Can't remember if you tried all load off and turn on Shore AC to inverter putting it into charging mode and does it still trip GFI.

This is true on some inverters, but not all. So worth looking up how the particular device is supposed to operate. Otherwise you might find yourself chasing around in circles.

 

[foggysail]

A few questions...

Did the your system ever work with your inverter while connected to shore power?

Does the system work when your AC shore power cable is removed?

What wattage is your inverter and about how heavy is it.....does it weigh over about 10-15 pounds?

 

[tiltrider1]

A few questions...

Did the your system ever work with your inverter while connected to shore power?

Does the system work when your AC shore power cable is removed?

What wattage is your inverter and about how heavy is it.....does it weigh over about 10-15 pounds?

The inverter and the ECLI Worked together for years.

If shore power is disconnected the Inverter works. If at that time I reset the ECLI nothing happens as no power is going through the ECLI.

I replaced the ECLI with standard breakers and everything is functioning normally. I used a clamp meter to test for leakage, results were inconclusive.

Inverter is 2000 watts and weighs more than 20 lbs. Trace M2012 unit.

At this point I am taking advantage of the situation to install a new grid paralleling inverter/charger system. The new unit should arrive on Monday.

 

[tiltrider1]

I have seen these break with as little as 5 milliamp deviation. Take VOLTAGE readings between all points black and white. My guess is that you will end up changing out some equipment. Sometimes the electronics simply can't endure the deviations.

There is no continuity between black and white or black and green or green and white. Except there is near short level resistance between the power in line junction on the inverter and ground. This leads me to believe there is some sort of failure with the inverter.

 

[foggysail]

The reason for my questions is many inverters sold are designed for vehicle applications and many times used on boats. They do not feature a grounded conductor as we see in a home AC power distribution system.

The reason for asking about weight was heavy inverters most likely use an internal power transformer which then isolates the inverter’s innards allowing them to feature a grounded conductor. No need to go further into circuit theory.

YEAH..... good move to go with an inverter charger, they use internal transformers. Mine is rated at 4KW