We have installed a very basic 1000 watt inverter on Nepenthe (1992 Legend 35.5) for the very rare AC requirements we may have while away. I wired the inverter from the house batteries with specified guauge cable, included a breaker bar in line and mounted the unit next to the shore power input socket on the boat. I was originally going to install an AC input breaker panel that would allow me to toggle between shore power or Inverter however since it trully is not going to be used that often, I opted to use a AC cable (Marinco) that plugs into the Shore power input on the the boat at one end and plugs into the inverter on the other end. It's about a 18 inch tail. Even though I dont expect to use it often I would like to power the boats outlets versus connecting an extension cord each time I want to use an AC device. When I go below I get a reverse polarity indicated on the panel. I tried using one of those three prong to two prong adapters that eliminates the ground wire just to see if I could eliminate the reverse polarity indicator however it remains solidly lit regardless of how I orient the connection to the inverter. I have read the archives about how a small amount of voltage can cause the same effect but this seams to be different. Additionally, would this issue cause any damage or issue with the wiring of the boat? Can someone give me some advice or direction on what I am missing? Thanks, Alex
Reverse Polarity inverter issue
- Thread starter Alex 2740
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Inverter reverse polarity
Alex, I had the same problem. The inverter does not have the normal output you would see on a 120vac outlets, i.e., 120vac from the hot lead (black) to ground or neutral, and 0 vac from the neutral side (white) to ground. Instead, the inverters (such as a xantrex that I installed) has approximately 60vac from the hot side to ground, as well as the neutral side to ground. But, you see the 120vac between the hot and neutral. In my case, my 120vac panel has a breaker that senses voltage on the neutral side, as well as a light to indicate 'reverse polarity'. I am not sure what the little device is, although it looks like a diode or something of that sort. I disconnected the 'device' so that the 'reverse polarity' from my inverter did not trip the breaker. To make a long story short, the 'reverse polarity' light is due to the approximately 60 volts seen from the neutral to ground. I assume you have circuitry so that you cannot power the inverter while you have shore power. Hope this helps, Michael
Alex, I had the same problem. The inverter does not have the normal output you would see on a 120vac outlets, i.e., 120vac from the hot lead (black) to ground or neutral, and 0 vac from the neutral side (white) to ground. Instead, the inverters (such as a xantrex that I installed) has approximately 60vac from the hot side to ground, as well as the neutral side to ground. But, you see the 120vac between the hot and neutral. In my case, my 120vac panel has a breaker that senses voltage on the neutral side, as well as a light to indicate 'reverse polarity'. I am not sure what the little device is, although it looks like a diode or something of that sort. I disconnected the 'device' so that the 'reverse polarity' from my inverter did not trip the breaker. To make a long story short, the 'reverse polarity' light is due to the approximately 60 volts seen from the neutral to ground. I assume you have circuitry so that you cannot power the inverter while you have shore power. Hope this helps, Michael
Double Check
Michael, I have a Heart 1500 (Xantrex) and don't have the problem you descriped. This sounds dangerous and you should confirm with Xantrex that this correct. Dave
Michael, I have a Heart 1500 (Xantrex) and don't have the problem you descriped. This sounds dangerous and you should confirm with Xantrex that this correct. Dave
Reverse polarity - double check
Regarding the 'reverse polarity'. I contacted xantrex (mine is the cheap one sold by Costco) and they did confirm that the voltage is as I described (similiar to a split phase you see with 220v). They said it was caused by the filter capacitors. I also checked the voltage output from my Honda 1000eu and a smaller 300w inverter, and I found the same condition. Oh well.. Michael
Regarding the 'reverse polarity'. I contacted xantrex (mine is the cheap one sold by Costco) and they did confirm that the voltage is as I described (similiar to a split phase you see with 220v). They said it was caused by the filter capacitors. I also checked the voltage output from my Honda 1000eu and a smaller 300w inverter, and I found the same condition. Oh well.. Michael
Hardware store
Alex Buy an inexpensive reverse polarity checker at a hardware store, and check out your outlets on board with that. If they're OK, your RP lights on board are glitched (i.e., just don't work with the inverter). Also, PLEASE, for your own good and safety, do some research on RP deeper than asking questions here. Buy a book or read up and take notes in a chandlerly or library. It's not that hard, there are only 3 blinkin' wires! RP has nothing to do with the ground wire. It is a reverse of the black and white wires in AC wiring. If the hardware store unit says it's OK you're fine. Stu
Alex Buy an inexpensive reverse polarity checker at a hardware store, and check out your outlets on board with that. If they're OK, your RP lights on board are glitched (i.e., just don't work with the inverter). Also, PLEASE, for your own good and safety, do some research on RP deeper than asking questions here. Buy a book or read up and take notes in a chandlerly or library. It's not that hard, there are only 3 blinkin' wires! RP has nothing to do with the ground wire. It is a reverse of the black and white wires in AC wiring. If the hardware store unit says it's OK you're fine. Stu
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