What on earth, no pun intended, is the problem when I get the the reverse polarity light on my electric panel. I have 2 orange lights that say NORMAL and one red that says REVERSED. The red on just blinks slowly and the Orange one are dark. I just put a new shore power plug in and am running off the 110v with a converter in the dry storage yard. I have reversed the green and black wires on the cable and at the outlet but nothing changes it. Is it in the charger set up or is it something different. No wild guesses now, I need to get this rolling tomorrow! Thanks.
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RP
Reverse polarity is when the white (neutral) and black (hot) wires are connected backwards. Not the green ground. Check the shore power itself first to see if it is properly polarized. If you don't have one yet, go to a hardware store and get a simple polarity tester (might be hard to do tomorrow, try borrowing one). Then check the wiring you did on your new shorepower connector on the boat to make sure you haven't crossed the black and white wires. By crossed I simply mean reversing where the black and white wires should go. Calder's has a very good explanation with pictures, West Marine is open tomorrow, go read up on it. In addition to your polarity panel lights, use the polarity tester on any of your on-board AC outlets. I assume that you've checked your panel polarity light(s) and they were OK before. Stu
Reverse polarity is when the white (neutral) and black (hot) wires are connected backwards. Not the green ground. Check the shore power itself first to see if it is properly polarized. If you don't have one yet, go to a hardware store and get a simple polarity tester (might be hard to do tomorrow, try borrowing one). Then check the wiring you did on your new shorepower connector on the boat to make sure you haven't crossed the black and white wires. By crossed I simply mean reversing where the black and white wires should go. Calder's has a very good explanation with pictures, West Marine is open tomorrow, go read up on it. In addition to your polarity panel lights, use the polarity tester on any of your on-board AC outlets. I assume that you've checked your panel polarity light(s) and they were OK before. Stu
Reverse polarity
Stu, thanks for the help. I was going to stay home today and work on this problem some more but, you have given me a reason to go visit the boat. What finer New Years present can one get. Thanks again I will try the things you suggest. Rick
Stu, thanks for the help. I was going to stay home today and work on this problem some more but, you have given me a reason to go visit the boat. What finer New Years present can one get. Thanks again I will try the things you suggest. Rick
Reverse Polarity - may not be
Rick, There was a discussion of this same topic in June 2004 ... check back in the archives. There are other possibilities discussed there. Dave
Rick, There was a discussion of this same topic in June 2004 ... check back in the archives. There are other possibilities discussed there. Dave
Wrote This Earlier
In response to a previous poster who asked the same question. This is can be a very dangerous situation, I'll try to explain. The light (a 110 volt neon light) is wired between the ground (green wire) and the neutral (white wire) of your shore power inlet. The neutral (white) and ground (green) wires should be at the same potential voltage wise. In other words, A voltmeter attached to the ground and neutral wires should read no voltage. If for some reason, the dock outlet, shore power inlet on the boat, or the shore power cord is miswired and reverses the hot (black wire) with the neutral wire, the light will come on to warn about the "reverse polarity. Reversed polarity connects the hot side of the shore power to the wrong side of various appliances you may have on your boat. For example, if you have an electric drill with a metal case, normally the case is connected to neutral, and the hot runs the motor. Reverse it, and now the case is hot! If you were holding the drill and contacted anything grounded, mast, keel bolts, engine, etc., ZZZAAAAAAAP! You become the conductor which is not good for your health. The bad part is that most appliances will work properly. This situation is like a snake waiting to strike. In this scenario, the reverse polarity light would be lit brightly. If the polarity light is lit only dimly, the problem is either a broken or bad ground or neutral wire. The problem could be as simple as a worn out shore power connector. That is why wriggling the connector will sometime correct the problem. If reseating the connector makes the light go out, the shore power connector (either the receptacle or the plug) is worn and needs to be replaced. Make sure you check both ends. This is dangerous as well since any fault in the tool or appliance will once again cause you to be the conductor if the right circumstances are present. The polarity could truly be reversed especially if the marina has had electrical work done recently, you've changed the shore power inlet on the boat, changed either end of the shore power cord, and less likely, bought a new shore power cord.
In response to a previous poster who asked the same question. This is can be a very dangerous situation, I'll try to explain. The light (a 110 volt neon light) is wired between the ground (green wire) and the neutral (white wire) of your shore power inlet. The neutral (white) and ground (green) wires should be at the same potential voltage wise. In other words, A voltmeter attached to the ground and neutral wires should read no voltage. If for some reason, the dock outlet, shore power inlet on the boat, or the shore power cord is miswired and reverses the hot (black wire) with the neutral wire, the light will come on to warn about the "reverse polarity. Reversed polarity connects the hot side of the shore power to the wrong side of various appliances you may have on your boat. For example, if you have an electric drill with a metal case, normally the case is connected to neutral, and the hot runs the motor. Reverse it, and now the case is hot! If you were holding the drill and contacted anything grounded, mast, keel bolts, engine, etc., ZZZAAAAAAAP! You become the conductor which is not good for your health. The bad part is that most appliances will work properly. This situation is like a snake waiting to strike. In this scenario, the reverse polarity light would be lit brightly. If the polarity light is lit only dimly, the problem is either a broken or bad ground or neutral wire. The problem could be as simple as a worn out shore power connector. That is why wriggling the connector will sometime correct the problem. If reseating the connector makes the light go out, the shore power connector (either the receptacle or the plug) is worn and needs to be replaced. Make sure you check both ends. This is dangerous as well since any fault in the tool or appliance will once again cause you to be the conductor if the right circumstances are present. The polarity could truly be reversed especially if the marina has had electrical work done recently, you've changed the shore power inlet on the boat, changed either end of the shore power cord, and less likely, bought a new shore power cord.
For Rodney-reverse polarity with a GFCI?
I recently re-wired a circuit in my boat's AC wiring when I found reverse polarity indicated on a seldom-used outlet. This outlet, however, wasn't hard-wired in to the AC system, it plugged into a GFCI outlet (kind of like an extension cord). The GFCI was correctly wired as per the polarity indicator. While I corrected the reverse polarity at the plug where it went into the GFCI outlet, I wondered if it was really that much of a problem, given that it ran thru a GFCI?
I recently re-wired a circuit in my boat's AC wiring when I found reverse polarity indicated on a seldom-used outlet. This outlet, however, wasn't hard-wired in to the AC system, it plugged into a GFCI outlet (kind of like an extension cord). The GFCI was correctly wired as per the polarity indicator. While I corrected the reverse polarity at the plug where it went into the GFCI outlet, I wondered if it was really that much of a problem, given that it ran thru a GFCI?
GFCI vs Reverse Polarity
Peter They're two different things. Rodney explained it (RP) very well. If the hot and neutral are backwards you stand the chance of getting zapped. GFCI means ground fault interruption. If the GFCI device senses a ground fault (short between the hot or neutral and ground wire) it shuts off, which is why there are reset buttons on the GFCI outlets. GFCI outlets protect regular outlets downstream. In your case, the downstream outlet was improperly wired (hot and neutral switched). The GFCI didn't trip, did it? They're two different protective devices / concepts. In your case, it WAS hard wired into the AC system, since it connected to a GFCI outlet that WAS wired into the AC system. It WAS a reverse polarity problem It wasn't a GF problem, even with the hot and neutral switched, it would've tripped on a GF if one had occurred. Peter, all this is based on my assumption that the "extension cord" was wired to the back of the GFCI outlet. In rereading your post, it could have been that the "extension cord" was simply plugged into the GFCI, which would seem to mean that the black and white wires at the back of the outlet at the far end of the "extension cord" were simply installed incorrectly. If you look at the outlet, it should say which screw to put the white wire on, the black goes on the other one. Stu
Peter They're two different things. Rodney explained it (RP) very well. If the hot and neutral are backwards you stand the chance of getting zapped. GFCI means ground fault interruption. If the GFCI device senses a ground fault (short between the hot or neutral and ground wire) it shuts off, which is why there are reset buttons on the GFCI outlets. GFCI outlets protect regular outlets downstream. In your case, the downstream outlet was improperly wired (hot and neutral switched). The GFCI didn't trip, did it? They're two different protective devices / concepts. In your case, it WAS hard wired into the AC system, since it connected to a GFCI outlet that WAS wired into the AC system. It WAS a reverse polarity problem It wasn't a GF problem, even with the hot and neutral switched, it would've tripped on a GF if one had occurred. Peter, all this is based on my assumption that the "extension cord" was wired to the back of the GFCI outlet. In rereading your post, it could have been that the "extension cord" was simply plugged into the GFCI, which would seem to mean that the black and white wires at the back of the outlet at the far end of the "extension cord" were simply installed incorrectly. If you look at the outlet, it should say which screw to put the white wire on, the black goes on the other one. Stu
Stu-a clarification
The PO had installed (correctly) the GFCI outlets. He'd then cut the original polarized plug off a 3-wire (hot, neutral & ground) outdoor extension cord, as the cable needed to run from the downstream outlet to the GFCI behind a liner that wouldn't allow enough room to pull the original plug thru. After pulling the cable, he then installed another (polarized) plug onto the wire, but apparently wired the hot and neutral backwards. The new plug then plugged in to the front of the GFCI, like any extension cord. My thought was that, if I effectively became the neutral wire, due to touching the chassis of whatever I'd plugged into the outlet at the end of the cord with now-reversed polarity, I'd still be OK due to the GFCI sensing the ground fault. Am I wrong? Note that I did correct the reverse polarity. Even if the GFCI would protect me, I don't like relying on one mode of protection. I carry 2 GPS units, have a loran, and plot DR frequently. I like to fix it before it breaks! Thanks!
The PO had installed (correctly) the GFCI outlets. He'd then cut the original polarized plug off a 3-wire (hot, neutral & ground) outdoor extension cord, as the cable needed to run from the downstream outlet to the GFCI behind a liner that wouldn't allow enough room to pull the original plug thru. After pulling the cable, he then installed another (polarized) plug onto the wire, but apparently wired the hot and neutral backwards. The new plug then plugged in to the front of the GFCI, like any extension cord. My thought was that, if I effectively became the neutral wire, due to touching the chassis of whatever I'd plugged into the outlet at the end of the cord with now-reversed polarity, I'd still be OK due to the GFCI sensing the ground fault. Am I wrong? Note that I did correct the reverse polarity. Even if the GFCI would protect me, I don't like relying on one mode of protection. I carry 2 GPS units, have a loran, and plot DR frequently. I like to fix it before it breaks! Thanks!
Clarification back
Peter "A GFCI monitors the amount of current going to and from a circuit. Whenever the amounts of incoming and outgoing current are not equal -indicating current leakage (a "ground fault") - the GFCI opens the circuit immediately (1/40 second)." [source: Sunset Book of Home Wiring - applicable to AC circuits on boats, too!] I understand your redundancy theory and subscribe to it. To answer your question: maybe. If your body was the ground, and you were a reasonably good conductor, the GFCI MAY not see any difference in the time that you were getting zapped. Just think of them as two separate things, not redundant. You can have reverse polarity and no ground fault. You can have a ground fault and no reverse polarity. And the other combinations. Ground faults usually occur because of loose connections. Reverse polarity occurs simply because the connections are backwards. Hope this helps. Trick is to get the wiring right and keep the connections secure. Secure connections are harder to do on a boat because of the vibration, so GFCI makes sense for when using shorepower and, even more now, with the increased use of inverters. For anybody with an inverter on-board that you use at anchor, it would be prudent to brush up on AC wiring. Stu
Peter "A GFCI monitors the amount of current going to and from a circuit. Whenever the amounts of incoming and outgoing current are not equal -indicating current leakage (a "ground fault") - the GFCI opens the circuit immediately (1/40 second)." [source: Sunset Book of Home Wiring - applicable to AC circuits on boats, too!] I understand your redundancy theory and subscribe to it. To answer your question: maybe. If your body was the ground, and you were a reasonably good conductor, the GFCI MAY not see any difference in the time that you were getting zapped. Just think of them as two separate things, not redundant. You can have reverse polarity and no ground fault. You can have a ground fault and no reverse polarity. And the other combinations. Ground faults usually occur because of loose connections. Reverse polarity occurs simply because the connections are backwards. Hope this helps. Trick is to get the wiring right and keep the connections secure. Secure connections are harder to do on a boat because of the vibration, so GFCI makes sense for when using shorepower and, even more now, with the increased use of inverters. For anybody with an inverter on-board that you use at anchor, it would be prudent to brush up on AC wiring. Stu
Great Little Test Device
Years ago (80's) I replaced my AC outlets on my 1972 Coronado. Not being a genius when it comes to AC/DC work, I purchased at Sear's a nifty three prong, plug in "Reverse Polarity" indicator that had three lights that advised you once plugged into the receptacle if you were essentially wired properly. I recently purchased one again as I am doing the same receptacle replacement thing in my home. Cheap insurance and literally fail safe. Regards Bob Atlanta
Years ago (80's) I replaced my AC outlets on my 1972 Coronado. Not being a genius when it comes to AC/DC work, I purchased at Sear's a nifty three prong, plug in "Reverse Polarity" indicator that had three lights that advised you once plugged into the receptacle if you were essentially wired properly. I recently purchased one again as I am doing the same receptacle replacement thing in my home. Cheap insurance and literally fail safe. Regards Bob Atlanta
Peter
Stu explained very well how the GFCI failed to trip in your particular case where the PO had wired the plug incorrectly. What a great thread!
Stu explained very well how the GFCI failed to trip in your particular case where the PO had wired the plug incorrectly. What a great thread!
Rodney
Actually, my question was a theoretical one. There had been no problem in the actual usage of the outlet/wiring. I was just wondering whether the GFCI would have protected me if I in fact "became the ground" in the circuit because of the R/P
Actually, my question was a theoretical one. There had been no problem in the actual usage of the outlet/wiring. I was just wondering whether the GFCI would have protected me if I in fact "became the ground" in the circuit because of the R/P
Peter
Well, it should work. A GFCI monitors the amount of current flowing on the hot and neutral conductors. In a perfect circuit, the current in both conductors should be equal. If there is any imbalance, it trips the circuit. The assumption is that if there is not an equal amount of current on the hot and neutral conductors, the difference must be running through the ground (green) conductor and that defines a ground fault. In your theoretical case, the fact that the GFCI senses a difference in the current flowing on the hot and neutral conductors means the GFCI would have tripped anyway even if the conductors "downstream" were reversed. The key here is that it doesn't matter which conductor has more or less current than the other - the circumstance where they are not equal will cause the GFCI to trip. The GFCI is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second. You may receive a nasty shock but shouldn't be electrocuted. Clear as mud?
Well, it should work. A GFCI monitors the amount of current flowing on the hot and neutral conductors. In a perfect circuit, the current in both conductors should be equal. If there is any imbalance, it trips the circuit. The assumption is that if there is not an equal amount of current on the hot and neutral conductors, the difference must be running through the ground (green) conductor and that defines a ground fault. In your theoretical case, the fact that the GFCI senses a difference in the current flowing on the hot and neutral conductors means the GFCI would have tripped anyway even if the conductors "downstream" were reversed. The key here is that it doesn't matter which conductor has more or less current than the other - the circumstance where they are not equal will cause the GFCI to trip. The GFCI is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second. You may receive a nasty shock but shouldn't be electrocuted. Clear as mud?
Portable Tester
Bob's right, the portable tester (3 prong) is what I mentioned in the earlier post. Not only do we have RP lights on our panel, but we also have the tester, which I use in addition to the panel especially when we plug into a new marina when traveling. Peter, there's redundancy for ya! Stu
Bob's right, the portable tester (3 prong) is what I mentioned in the earlier post. Not only do we have RP lights on our panel, but we also have the tester, which I use in addition to the panel especially when we plug into a new marina when traveling. Peter, there's redundancy for ya! Stu
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