Skybolt
Well-Known Member
- Nov 11, 2014
- 6,479
- Boat Info
- Reel Nauti
460 EC
- Engines
- Detroit 6v92TA
(Low profile's)
Alison Gears
Westerbeke
12.5kw Genset
I am trying to be pro active with the issue of your boat tripping the dockside GFCI when you know there nothing wrong with your boat. BTW, that's never the case. My marina is about to upgrade the docks which means new GFCI power.
I have had issues this past summer with new docks and my boat tripping the pedestal GFCI. In checking out my boat I found issues that I never knew existed. I also haven't resolved this issue completely.
First what do I think I know about this? (From the dockside power perspective)
1. Ground (green wire) and Neutral (white wire) should never be connected together like in house wiring.
2. The ground wire should be connected to the DC ground.
3. There can not be more then 30mA of reverse current going back to the dock breaker.
4. There can not be an imbalance in voltage between the hot and neutral legs to/from the boat.
5. There should be a virtual open between the ground and neutral wires.
6. Hot to ground can not have any leakage, which causes this to occur.
7. The led(s) that show reverse polarity and power can cause issues as they bridge the hot and ground and neutral to a degree.
8. Just turning off all of the breakers will only stop leakage and not help with ground and neutral issues.
Is there more that needs to be taken into consideration?
30mA are they kidding me! How do you limit that when new electronics can produce that by itself when they are not rated for marine use, but ok, it is what it is. I think ultimately an isolation transformer will fix the dock breaker from tripping, but won't fix the boat issues.
This type of issue can take a very, very long time to resolve completely unless you get lucky. I am considering setting up a GFCI plug to go from a non GFCI outlet to the boat to be able to test this. I think a 50A hot tub box could be used if wired with marine plugs, just for testing. Although this will just tell you if it's fixed. Will just measuring revers current and ground/neutral resistance be sufficient?
So how do you test this without using the above? Find and fix any ground to neutral resistance, this could mean replacing electronics/appliances and entire wire runs. That will stop the GFCI from popping, but how to fix/find the hot to ground leakage current? That is the toughest one and I believe where the test GFCI will come in handy to isolate the offending lines. Turning breakers off will help isolate this issue but still a daunting task to resolve.
Older boats will see higher leakage current then newer ones as the jacketing deteriorates causing leakage, even though the lines are not shorted and to the observer appears to be nothing wrong with the wiring. Even when ohm'd out there will be nothing wrong in most cases. It takes voltage and current to cause leakage, very hard to find.
I started to investigate my issues and found a bad wire run that was only a few years old. It looked fine and worked as expected, but with the breakers off and the outlet pulled I found continuity between the ground and neutral causing a few volts to appear on the ground system. Man how long had that been going on. I replaced that run with a new wire and all is good.
I still have ~400mv between the ground and neutral at the panel when it should be close to zero. Just ordered a new ring current meter so I can see what that translates into. I am hoping if I can get the ground and neutral to look like an open and the reverse current to under 30mA I won't need the test cable. But man this is a daunting issue to track down. Not to mention a lot of up, down, plug, unplugging the boat. Removing needed led indicators and the like.
I am only posting this to help me think through the process of testing and see if anyone else has had to go through this. Before anyone ask's I do not have an inverter and only use the generator. At my panel there is a three breaker disconnect the switches the two hot leads and the neutral between the generator and shore power. My generator does have the ground and neutral connected as it was intended to be. ABYC and NEC dictate the neutral and ground should be connected only at the source. When on generator that is the source.
Is an isolation transformer the only real fix for this? And if I do add one do I also need an ELCI breaker on the boat as well? I just replaced my entire electrical panel a few years ago with all new Blue Sea ABYC compliant panels and the like. Man that could be upwards of 4K to get back what I already have. Not to mention replacing my panel again to do it right. Oh man this sucks!
I have had issues this past summer with new docks and my boat tripping the pedestal GFCI. In checking out my boat I found issues that I never knew existed. I also haven't resolved this issue completely.
First what do I think I know about this? (From the dockside power perspective)
1. Ground (green wire) and Neutral (white wire) should never be connected together like in house wiring.
2. The ground wire should be connected to the DC ground.
3. There can not be more then 30mA of reverse current going back to the dock breaker.
4. There can not be an imbalance in voltage between the hot and neutral legs to/from the boat.
5. There should be a virtual open between the ground and neutral wires.
6. Hot to ground can not have any leakage, which causes this to occur.
7. The led(s) that show reverse polarity and power can cause issues as they bridge the hot and ground and neutral to a degree.
8. Just turning off all of the breakers will only stop leakage and not help with ground and neutral issues.
Is there more that needs to be taken into consideration?
30mA are they kidding me! How do you limit that when new electronics can produce that by itself when they are not rated for marine use, but ok, it is what it is. I think ultimately an isolation transformer will fix the dock breaker from tripping, but won't fix the boat issues.
This type of issue can take a very, very long time to resolve completely unless you get lucky. I am considering setting up a GFCI plug to go from a non GFCI outlet to the boat to be able to test this. I think a 50A hot tub box could be used if wired with marine plugs, just for testing. Although this will just tell you if it's fixed. Will just measuring revers current and ground/neutral resistance be sufficient?
So how do you test this without using the above? Find and fix any ground to neutral resistance, this could mean replacing electronics/appliances and entire wire runs. That will stop the GFCI from popping, but how to fix/find the hot to ground leakage current? That is the toughest one and I believe where the test GFCI will come in handy to isolate the offending lines. Turning breakers off will help isolate this issue but still a daunting task to resolve.
Older boats will see higher leakage current then newer ones as the jacketing deteriorates causing leakage, even though the lines are not shorted and to the observer appears to be nothing wrong with the wiring. Even when ohm'd out there will be nothing wrong in most cases. It takes voltage and current to cause leakage, very hard to find.
I started to investigate my issues and found a bad wire run that was only a few years old. It looked fine and worked as expected, but with the breakers off and the outlet pulled I found continuity between the ground and neutral causing a few volts to appear on the ground system. Man how long had that been going on. I replaced that run with a new wire and all is good.
I still have ~400mv between the ground and neutral at the panel when it should be close to zero. Just ordered a new ring current meter so I can see what that translates into. I am hoping if I can get the ground and neutral to look like an open and the reverse current to under 30mA I won't need the test cable. But man this is a daunting issue to track down. Not to mention a lot of up, down, plug, unplugging the boat. Removing needed led indicators and the like.
I am only posting this to help me think through the process of testing and see if anyone else has had to go through this. Before anyone ask's I do not have an inverter and only use the generator. At my panel there is a three breaker disconnect the switches the two hot leads and the neutral between the generator and shore power. My generator does have the ground and neutral connected as it was intended to be. ABYC and NEC dictate the neutral and ground should be connected only at the source. When on generator that is the source.
Is an isolation transformer the only real fix for this? And if I do add one do I also need an ELCI breaker on the boat as well? I just replaced my entire electrical panel a few years ago with all new Blue Sea ABYC compliant panels and the like. Man that could be upwards of 4K to get back what I already have. Not to mention replacing my panel again to do it right. Oh man this sucks!