Inverter’s GFI Trips when battery switch goes to 1, 2 or both position.

[Jarana]

Hi again,
I tried the new one exactly with the same result, GFI trips as soon as I turn the switch on even if the DC panel is off.
I must assume now that there is a leakage somewhere at the DC circuit.
I am using a tester to see if i can find it tomorrow.
I ended up grounding the case of the inverter to the battery negative with a thick 2/0 wire as CharlieJ indicated.

We will see, but this is a mystery.

[CharlieJ]

A GFCI operates by measuring the current being supplied on line (L, black) and being returned on neutral (N, white). The safety ground wire (G, green) has absolutely nothing to do with the operation of the GFCI. If the current supplied by L is different from the current returned on N by > 5 mAAC, then the GFCI trips. There is no direct interaction between a properly installed DC system and a GFCI.

Does the inverter supply AC loads, loads actually operating, when the AC source selector switch is selecting the inverter and the 1-2-BOTH switch is OFF??

Are you switching either the shore power G or the inverter output G with the AC source selector switch?

[Jarana]

Hi,
I have spent most of my day testing the new inverter and these are the conclusions:
1- The inverter works fine to power any device and it does not matter if the battery switch is on or off. The appliances work fine with the batteries in Off, 1 2 or Both position.
2- The inverter powers the AC panel fine only when batteries are Off. I tested the system using the microwave powered by the inverter. I had the battery switch always off.
if the battery switch turns on it takes about 5 to 8 seconds to trip the inverter's GFI and this GFI can not be reseted until the batteries are back to Off position.

I installed a changeover switch at the shore power line to the AC panel. this changeover switch allows to decide if the AC panel gets power from shore (Position 1) or from the inverter (Position 2).Both position give continuity to the three cables L, N and G but from different sources.

I have read that some GFI inverters are not a good choice to connect to AC panels. the following is what i read.

"The two most common situations where GFCI outlets trip are when plugging in shore power or wiring up to an electrical panel.
We can conclude there is an incompatibility when we consider the sensitivity of the outlets and that they were designed to protect you from a single appliance being plugged in.
What happens is an electrical panel and/or the AC wiring can cause the GFCI to detect a discrepancy between line and neutral, as if there was a ground leak, even though there is not.
If you need to energize an entire boat, or electrical panel, I would recommend staying away from inverters that only have outlets. Inverters with a 3-wire AC hardwire terminal block option are designed and much better suited for these types of installations.
These types of inverters with AC hardwire capability will often come with GFCI outlets as an option as well. I do not recommend altering the GFCI outlets or bypassing the ground prong as this can lead to other problems or hazards.
Inverters with outlets only are suitable for plugging devices directly in or energizing a single 15-20 Amp circuit. Referring to how a GFCI outlets work and the purpose of ground fault protection is the most effective tool in preventing issues. Do not expect GFCI’s to do something they were not designed for".
what are your thoughts?
Can I fix the AC connection? or should I return the inverter and buy one with 3 wire terminal block?

Thanks.

[wingssail]

Originally Posted by Jarana

Hi,
I have spent most of my day testing the new inverter and these are the conclusions:
1- The inverter works fine to power any device and it does not matter if the battery switch is on or off. The appliances work fine with the batteries in Off, 1 2 or Both position.
2- The inverter powers the AC panel fine only when batteries are Off. I tested the system using the microwave powered by the inverter. I had the battery switch always off.
if the battery switch turns on it takes about 5 to 8 seconds to trip the inverter's GFI and this GFI can not be reseted until the batteries are back to Off position.

I installed a changeover switch at the shore power line to the AC panel. this changeover switch allows to decide if the AC panel gets power from shore (Position 1) or from the inverter (Position 2).Both position give continuity to the three cables L, N and G but from different sources.

I have read that some GFI inverters are not a good choice to connect to AC panels. the following is what i read.

"The two most common situations where GFCI outlets trip are when plugging in shore power or wiring up to an electrical panel.
We can conclude there is an incompatibility when we consider the sensitivity of the outlets and that they were designed to protect you from a single appliance being plugged in.
What happens is an electrical panel and/or the AC wiring can cause the GFCI to detect a discrepancy between line and neutral, as if there was a ground leak, even though there is not.
If you need to energize an entire boat, or electrical panel, I would recommend staying away from inverters that only have outlets. Inverters with a 3-wire AC hardwire terminal block option are designed and much better suited for these types of installations.
These types of inverters with AC hardwire capability will often come with GFCI outlets as an option as well. I do not recommend altering the GFCI outlets or bypassing the ground prong as this can lead to other problems or hazards.
Inverters with outlets only are suitable for plugging devices directly in or energizing a single 15-20 Amp circuit. Referring to how a GFCI outlets work and the purpose of ground fault protection is the most effective tool in preventing issues. Do not expect GFCI’s to do something they were not designed for".
what are your thoughts?
Can I fix the AC connection? or should I return the inverter and buy one with 3 wire terminal block?

Thank You,

I found that my inverter has a connection from green to white (AC side). This I found in the wiring diagram.

When I connected the green to the outlet boxes they became hot. I got a tingle when I brushed my bare leg against a metal outlet plate.

I am sure that if I connected the ship's ground to the AC Ground (green) it would trip the GFI breaker.

So, in your case, I would make sure that the green wire from the inverter is NOT CONNECTED to anything.

If that solves your problem then you need to find out where the AC system is connected to the ship's ground system, and probably that means to the sea water somewhere.

[smac999]

Pretty much everything in the above post is wrong. You are a danger to yourself and others.


The green and white will be connected together on a marine inverter. This is correct The green from the inverter should defiantly be connected to the boats ac ground. And the boats dc ground should be connected to the ac ground.

Your gfi inverter should work with all the above if there are no boat issues. Obviously you have a boat wiring issue. Both of you.

Sure you could replace the inverter with one that does not have gfi. But your boat will still have a problem. One that may be unsafe.

Instead of replacing the inverter. Find and Fix the issue.


I still have no idea how a battery switch would trip a gfi though...

[wingssail]

Originally Posted by smac999

Pretty much everything in the above post is wrong. You are a danger to yourself and others.


The green and white will be connected together on a marine inverter. This is correct The green from the inverter should defiantly be connected to the boats ac ground. And the boats dc ground should be connected to the ac ground.

Your gfi inverter should work with all the above if there are no boat issues. Obviously you have a boat wiring issue. Both of you.

Sure you could replace the inverter with one that does not have gfi. But your boat will still have a problem. One that may be unsafe.

Instead of replacing the inverter. Find and Fix the issue.


I still have no idea how a battery switch would trip a gfi though...

This is where we run into problems. If the green and the white are connected, then there is AC potential on the green wire.

If you then attach the green wire to, for example, your metal outlet boxes, they will be HOT. For sure the screws to your baseplate will be hot, and if you have metal base plates, they will be hot.

If you mr smac999 doubt that, I suggest you try it. Maybe put your tongue on one of the screws.

Then, if you have not shocked yourself, you can connect the AC Ground (green) to the ship's DC ground. Now the entire DC system will be hot, however this will not shock you because any stray AC will be running directly to the sea through the bonding system. You may experience some rather rapid electrolysis however.

As to why closing the battery switch might trigger the GFI fault? I am not sure, but possibly the switch is connecting the DC ground to the battery and thence to the sea through the bonding system. That is a puzzler.

You know, we've just had a rather long thread about how "important" it is to have professional electricians do your boat's electrical system and I demurred because I had experience with people who want to make connections like you suggest.

Then you come along and prove it.

Pro does not mean smart.

BTW, there are quite a few comments "above". If you want to be sure you are referring to a specific comment to which you object, just reply with the "quote" button.

[boatpoker]

Originally Posted by smac999

Pretty much everything in the above post is wrong. You are a danger to yourself and others.


The green and white will be connected together on a marine inverter. This is correct The green from the inverter should defiantly be connected to the boats ac ground. And the boats dc ground should be connected to the ac ground.

Your gfi inverter should work with all the above if there are no boat issues. Obviously you have a boat wiring issue. Both of you.

Sure you could replace the inverter with one that does not have gfi. But your boat will still have a problem. One that may be unsafe.

Instead of replacing the inverter. Find and Fix the issue.


I still have no idea how a battery switch would trip a gfi though...

Smac is 100% correct. Somewhere on your boat (other than your inverter) you have a ground/neutral bond (not good). If your AC ground is connected to your DC negative (as it should be) you will have an imbalance and trip your GFI.

Sometimes you just have to invest in a pro. You can hurt yourself playing with this.

[wingssail]

Originally Posted by boatpoker

Smac is 100% correct. Somewhere on your boat (other than your inverter) you have a ground/neutral bond (not good). If your AC ground is connected to your DC negative (as it should be) you will have an imbalance and trip your GFI.

Sometimes you just have to invest in a pro. You can hurt yourself playing with this.

What I think is wrong about your assumption is that you assume the boat's wiring is defective. It may be.

However, if there is a resistance in either the boat's AC wiring or the shore power wiring such that the AC, which we've now put on the green wire, prefers to find an alternative path to ground, then you have the condition the OP has discovered.

What you, boatpoker, and you smac999, are obstinately ignoring, is that the connection between the white and green puts AC on the green wire, which makes it HOT, and it therefore will let AC flow to the ground if there is a path. Just please address that issue instead of falling back on your dogma.

I hired a pro once, and he did not understand the automatic function of my inverter, so he was surprised when the outlets remined hot after he flipped off the shore power switch. So he cut the wires on my boat. I'll never forgive the profession for that act of arrogance and when you guys parrot your dogma, I know the apple has not fallen far from the tree.

[Uncle Bob]

Originally Posted by wingssail

I found that my inverter has a connection from green to white (AC side). This I found in the wiring diagram.

When I connected the green to the outlet boxes they became hot. I got a tingle when I brushed my bare leg against a metal outlet plate.

I am sure that if I connected the ship's ground to the AC Ground (green) it would trip the GFI breaker.

So, in your case, I would make sure that the green wire from the inverter is NOT CONNECTED to anything.

If that solves your problem then you need to find out where the AC system is connected to the ship's ground system, and probably that means to the sea water somewhere.

Hi, I am trying to understand your quote. You say that the hotwire and the ground wire are connected within the inverter making the ground of the inverter dangerous? Surely the product is defective and inherently unsafe, is it not?

[wingssail]

Originally Posted by Uncle Bob

Hi, I am trying to understand your quote. You say that the hotwire and the ground wire are connected within the inverter making the ground of the inverter dangerous? Surely the product is defective and inherently unsafe, is it not?

Well technically speaking the white is neutral, but you are correct. That's because in North America, on boats, we have only white and black to carry the AC load, the white is a power lead. The internal connection between white and green makes the ground wire (the green wire) dangerous. This shocked me (no pun intended) when I discovered it many years ago. I had diligently connected the green wire to the AC grounding system, including the metal outlet boxes, and, surprise, they all became hot.

The wiring diagram of the inverter confirmed that connection. Today smac999 and boatpoker also asserted that this was a proper connection. They are, however, silent on the point that green and white makes green HOT.

And, if your boat's DC grounding system is connected to the AC ground, then your AC finds a new home.

[smac999]

Connecting the white to ground makes the white grounded. Not hot.. that is what decides which wire is hot or not. Instead of floating. In North America.

You know every house and every dock and every marine generator also has the green and white bonded right?. As well as every marine inverter.

If you are running off shore power, on-board gen, or on-board inverter. The green and white are always connected at the source.

That is how the power system is.

If you are getting current or voltage on the green. You either have a wiring or appliance problem.

[mitiempo]

Originally Posted by smac999

Connecting the white to ground makes the white grounded. Not hot.. that is what decides which wire is hot or not. Instead of floating. In North America.

You know every house and every dock and every marine generator also has the green and white bonded right?. As well as every marine inverter.

If you are running off shore power, on-board gen, or on-board inverter. The green and white are always connected at the source.

That is how the power system is.

If you are getting current or voltage on the green. You either have a wiring or appliance problem.

Smac and Boatpoker are totally correct. The green and white are always connected at the source. This is true of the shorepower transformer as well as any on board inverters or generators. In a properly wired system there is no voltage between the neutral (white) and ground (green) wires. 120 volts can only be measured between either white or green combined with the black (hot) wire.

It is not the inverter. There is a fault in the boat's wiring causing the problem. Certainly strange that it relates to the battery switch.

Hire a professional to find the issue. AC is nothing to play with if you do not know what you are doing.

[Maine Sail]

Originally Posted by mitiempo

Smac and Boatpoker are totally correct. The green and white are always connected at the source.

.

The key to all this is that the neutral to grounding “bond” is broken by the inverters internal or external transfer switch, when it is not actually “inverting”. This is a common problem when owners choose an inverter not ideally intended for use on a boat.

Simple test:
#1 Unplug from shore power
#2 Make sure invert function is off
#3 Test for continuity between your AC Neutral bus and AC Grounding bus

[Maine Sail]

Originally Posted by roland stockham

US regs insist on common A/C, D/C and corrosion grounds, Europe prohibits it!

I don't know exactly how to interpret this sentence, but will try to clarify the AC to DC grounding bond for US vs. ISO/RCD..

Interestingly enough many folks are shocked when they learn that the ISO/RCD standards are very similar to the ABYC in regards to the AC/DC bond as well as generator or inverter neutral to ground bond when operating away from shore power etc..

Sadly we only tend to read on the forums that it is the ABYC which is the sole out-liar on the AC grounding to DC grounding bond, but the ISO is right there with the ABYC on this point. The difference is that the ABYC is a voluntary standard and the ISO/RCD is a law.

The only point where they vary is that the ISO does allow an exception to the AC/DC grounding bond, if a whole boat RCD is fitted. The ABYC requires an ELCI plus the AC/DC bond.

ISO Small craft — Electrical systems — Alternating current installations

"4 General requirements

4.1 The protective conductor insulation shall be green or green with a yellow stripe. Neither colour shall be used for current-carrying conductors.

NOTE The equipotential bonding conductor of the d.c. electrical system (see ISO 10133) also uses green, or green with a yellow stripe, insulation and is connected to various exposed conductive parts of direct-current electrical devices, other extraneous conductive parts and the d.c. negative ground/earth.

4.2 The protective conductor shall be connected to the craft's d.c. negative ground (earth) as close as practicable to the battery (d.c.) negative terminal.

NOTE If an RCD (whole-craft residual current device) or an isolation transformer is installed in the main supply circuit of the a.c. system (see 8.2), the negative ground terminal of the d.c. system need not be connected to the a.c. shore ground (protective conductor)."

Just like the ABYC standards, the AC grounding to DC ground bond is a requirement under the ISO standards, which are LAW. They do however allow for an "exception" if a whole boat RCD or isolation transformer is fitted. Unfortunately the number of EU boats we work on that actually have an RCD fitted is quite low. Newer models, yes, but older models they seem as rare as an ELCI fitted US boat...

ABYC is voluntary, not Federal law, yet does not allow for an exception even if a whole boat ELCI is fitted (very similar to an RCD). This is because the ABYC decided the failure rate of such devices was just too high to allow for such an exception.

So in Europe ISO 13297, and the rest of the ISO standards, are law that requires the AC/DC grounding bond, (with an exception) but yet the voluntary standards of the ABYC seem to always the bad guys on this point??

[CharlieJ]

Jarana:
I asked you directly (#17) if the AC source selection switch was switching ground (G). Your #18 implied that the switch is switching L, N and G. If it is, than it is incorrectly wired. The safety ground wire (G) is not to be switched and his may be causing part of the problem.

Wingsail:
Your comments are regarding H, N and G are wrong.

For 120VAC service in the USA, current is supplied on the hot (L, Black) conductor and returns on the neutral (N, white) conductor. The safety ground (G, Green) conductor is bonded at all sources (generator, inverter inverting, secondary of isolation transformer, etc.) to provide a redundant, low impedance current path back to the source so that fault current that develops in a component will have two paths back to the source and will trip a protective device (fuse or circuit breaker).

Further, any mismatch between current supplied on H and returned on N will trip a ground fault protection device (RCD, GFCI, ELCI, etc.) when the mismatch exceeds a threshold.

MaineSail #28 & #29 are spot on.