This AC electrical puzzel doesn't seem to have an logical answer. One week everything works, the next weekend a problem. When connected to 30A shore power, the panel's reverse polarity light is now on and the meter reads only 50V instead of 120V. Our 356 has 2 AC shore power lines, line 2 powers only the air conditioner, while line 1 feeds everything else and can be cross-fed to also power the air conditioner. The puzzel is that if only line 2 is connected, everything is fine, 120V and no reverse polarity. But when line 1 is connected, only 50V and reverse polarity. This should rule out shore power to the boat as the problem. Since AC isn't my forte, I thought this forum might like a shot at this before I bring in the professionals.
Electrical Puzzel - for the AC buffs
- Thread starter Steve Korich
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No takers?
I would not even venture a guess without a wiring diagram. Maybe a Hunter owner with a similarly wired boat has a diagram and the experience. If, as I suspect, the two AC sources meet behind the panel then it could be many things. Have you checked the documentation, there is no combination of circuit breakers that can cause a problem? Does line 1 also go to an inverter/charger? If so have you turned off the inverter as one of your tests?
I would not even venture a guess without a wiring diagram. Maybe a Hunter owner with a similarly wired boat has a diagram and the experience. If, as I suspect, the two AC sources meet behind the panel then it could be many things. Have you checked the documentation, there is no combination of circuit breakers that can cause a problem? Does line 1 also go to an inverter/charger? If so have you turned off the inverter as one of your tests?
Thanks for the puzzle Oakless.
I've read your post several times. Each time I'm driven to ask for a schematic of your wiring. Then I keep reading that you don't know anything about this stuff. Oh well. AC is not all that complex. I'm no pro but I'll wager the problem is in the cross feed for the air conditioner. I was going to suggest that you undo the cross feed but do you know how,,? You also mention that sometimes everything works fine. More info needed on that one too. Does it only work fine when the air conditioning system is running?
I've read your post several times. Each time I'm driven to ask for a schematic of your wiring. Then I keep reading that you don't know anything about this stuff. Oh well. AC is not all that complex. I'm no pro but I'll wager the problem is in the cross feed for the air conditioner. I was going to suggest that you undo the cross feed but do you know how,,? You also mention that sometimes everything works fine. More info needed on that one too. Does it only work fine when the air conditioning system is running?
puzzel - more info
Thanks for the response. I don't have a handy wiring diagram, sorry. As for the problem as I said it is new. Everything worked fine a week ago. No it consistently doen't work, so it is not intermittent. Answers: the reverse polarity appears as soon as the line 1 power is turned on, regardless of whether the cross feed is on and without any other devises powered. The cross feed is locked out and cannot be enabled when line 2 is powered, so I am unable to get power to the battery charger from line 2. Turning on a line 1 devise only pops the breaker (example the battery charger will pop the breaker. Therefore it doesn't apear to be "downstream" from the main breaker to line 1.
Thanks for the response. I don't have a handy wiring diagram, sorry. As for the problem as I said it is new. Everything worked fine a week ago. No it consistently doen't work, so it is not intermittent. Answers: the reverse polarity appears as soon as the line 1 power is turned on, regardless of whether the cross feed is on and without any other devises powered. The cross feed is locked out and cannot be enabled when line 2 is powered, so I am unable to get power to the battery charger from line 2. Turning on a line 1 devise only pops the breaker (example the battery charger will pop the breaker. Therefore it doesn't apear to be "downstream" from the main breaker to line 1.
Sorry, there's no way to solve the problem on-line
without a schematic. Even that would probably not work because a schematic would likely show wiring as it was intended to be; done correctly. Your setup is incorrect. Call a pro.
without a schematic. Even that would probably not work because a schematic would likely show wiring as it was intended to be; done correctly. Your setup is incorrect. Call a pro.
Check with the marina...
Check with the marina, and ask if any AC work was done. The reason for the "Reverse Polarity" light, is to let YOU know when the AC "Hot" & "Neutral" has been reversed at the marina AC supply lines. Ask other boaters on the same dock if they have reversed lights on. Also, one of the ac lines "in the water" can cause some problems also. AC is not intermittent, it is good or it is not. Voltage dropping out can be intermittent, but not reverse polarity. That is caused by SOMEONE putting an c line in the wrong place.
Check with the marina, and ask if any AC work was done. The reason for the "Reverse Polarity" light, is to let YOU know when the AC "Hot" & "Neutral" has been reversed at the marina AC supply lines. Ask other boaters on the same dock if they have reversed lights on. Also, one of the ac lines "in the water" can cause some problems also. AC is not intermittent, it is good or it is not. Voltage dropping out can be intermittent, but not reverse polarity. That is caused by SOMEONE putting an c line in the wrong place.
Oakless...
Swap your shore power cables at the inlet on the boat. See if the problem travels to Line 2. If so then the problem is in the cord of pedastal on the dock. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
Swap your shore power cables at the inlet on the boat. See if the problem travels to Line 2. If so then the problem is in the cord of pedastal on the dock. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
Helping to diagnose the problem
Good thought Pat. I swapped the shore to line 2 and got a feed without the reverse polarity light coming on. I haven't yet talked to the marina to see if others are having a problem. I'm having trouble believing this is a boat wiring problem since it was fine for two years and this appeared suddenly in the last week. I can't think of what devise could fail in the system to cause the problem (both a voltage drop from 120v to 50v AND the reverse polarity.
Good thought Pat. I swapped the shore to line 2 and got a feed without the reverse polarity light coming on. I haven't yet talked to the marina to see if others are having a problem. I'm having trouble believing this is a boat wiring problem since it was fine for two years and this appeared suddenly in the last week. I can't think of what devise could fail in the system to cause the problem (both a voltage drop from 120v to 50v AND the reverse polarity.
Oakless, please understand that guys here,
like me and several others, are DRIVEN to solve problems for our fellow sailors. But we really need as much information as possible RIGHT AWAY. Adding a later post that says the problem just started a week ago is frustrating. That changes a lot of things.
like me and several others, are DRIVEN to solve problems for our fellow sailors. But we really need as much information as possible RIGHT AWAY. Adding a later post that says the problem just started a week ago is frustrating. That changes a lot of things.
My next step...
Would be to put a volt meter on the cord or pedestal and follow the problem up stream. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
Would be to put a volt meter on the cord or pedestal and follow the problem up stream. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
ac problems
Oakless, your problem is most likely in the shore wiring-ac feeds are several phases, where the ac voltages are out of sync-the marina probably is feeding two phases to the dock, and if you go across both of them you get 240 volt ac for large loads. If you connect to the hot from one phase and the neutral of the other, you will see about 50 volts and have weird effects-exactly what you're reporting. talk to the marina, it sounds like they've miswired your pedastel somehow
Oakless, your problem is most likely in the shore wiring-ac feeds are several phases, where the ac voltages are out of sync-the marina probably is feeding two phases to the dock, and if you go across both of them you get 240 volt ac for large loads. If you connect to the hot from one phase and the neutral of the other, you will see about 50 volts and have weird effects-exactly what you're reporting. talk to the marina, it sounds like they've miswired your pedastel somehow
Could Be Simple
My reverse polarity like used to come on when my shore power plug sagged at the dock connection. Our dock recepticles don't lock very well. Turns out it I was only picking up one leg of the line voltage triggering the reverse polarity light. Jeff
My reverse polarity like used to come on when my shore power plug sagged at the dock connection. Our dock recepticles don't lock very well. Turns out it I was only picking up one leg of the line voltage triggering the reverse polarity light. Jeff
Plugs
I had the same issue on my H380... It turns out the male plugs on the boat (both 1 and 2) had both failed (looked like they had been subject to some sorth of power surge) Relaced both plugs and the problem went away... Once pulling off the plugs you could see how the damage could have caused the problem... Brian CREW REST
I had the same issue on my H380... It turns out the male plugs on the boat (both 1 and 2) had both failed (looked like they had been subject to some sorth of power surge) Relaced both plugs and the problem went away... Once pulling off the plugs you could see how the damage could have caused the problem... Brian CREW REST
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