Reverse Polarity

bilge

.
Mar 26, 2016
5
Catalina 309 Mooloolaba
Hello Shipmates
We've hit a nasty problem with the reverse polarity light coming on with the shore power connected. It started as an intermittent fault and was resolved by putting a new plug on the shore power end and cleaning up the connections in the boat end plug. Unfortunately, it's back and not responding to previous treatment. We are in Australia so we're connected to 240V and have been adjusted accordingly but we still use an American plug at the boat end. It's looking more like an on-board problem. Any similar experiences? Cheers
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
Just had a similar problem 2 weeks ago. Checked the dock power pedestal to make sure it wasn't a problem. The ac power inlet on the transom looked suspect, so I changed it and the problem was solved. After researching reverse polarity on this site and others, there were several recommendations to turn on the main AC breaker on the main power panel where the reverse polarity light is located and turn off all the individual accessory circuit breakers. Then turn on one breaker at a time to determine what circuit is causing the reverse polarity. Then trace the problem from the accessory breaker to each accessory that is on that circuit. Problem with my situation was that with the main breaker on and the reverse polarity indicator on, none of the individual circuits would power up when their respective breakers were turned on. I guess that if the problem is before the main panel breaker, none of the accessory circuits can be activated for safety reasons. I also read that very high resistance can also cause the reverse polarity light to display even though it is not a real reverse polarity condition--- I don't know if that is factual. Hopefully some of the more knowledgeable people on the site can clarify.
 

bilge

.
Mar 26, 2016
5
Catalina 309 Mooloolaba
Thanks BEasy. I have all accessories turned off at the panel so it isn't a problem there. It appears the issue is between the shore supply and the main breaker on the panel. The shore supply is from our pontoon on our backyard canal so it's not a function of other boats connected. Thanks for your advice. will keep investigating. Cheers
 
Apr 3, 2012
95
Catalina 309 Sydney
Sorry I can't help you with that, but I was wondering what are the brackets on your transom for ?
 
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Johnb

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Jan 22, 2008
1,419
Hunter 37-cutter Richmond CA
Typically the reverse polarity lights when you have a difference in voltage between the neutral and ground. This could be caused by a genuine reversal of the live and neutral resulting in the reverse polarity light being connected between live and ground :yikes: or it could be caused by the neutral have a poor connection back to the source (dock), resulting in it being elevated in voltage relative to ground :yikes:.

If you are using the original connector on the boat has the hook up been bastardized with different cable ends to make it all work :yikes:. One way or another you should get someone who knows what they are doing to sort it out. Failure to do so may result in injury, death or horrible corrosion problems.
 

bilge

.
Mar 26, 2016
5
Catalina 309 Mooloolaba
Typically the reverse polarity lights when you have a difference in voltage between the neutral and ground. This could be caused by a genuine reversal of the live and neutral resulting in the reverse polarity light being connected between live and ground :yikes: or it could be caused by the neutral have a poor connection back to the source (dock), resulting in it being elevated in voltage relative to ground :yikes:.

If you are using the original connector on the boat has the hook up been bastardized with different cable ends to make it all work :yikes:. One way or another you should get someone who knows what they are doing to sort it out. Failure to do so may result in injury, death or horrible corrosion problems.
Good answer johnb. I have a marine electrician visiting next week as the issue has gone past my meagre talents. Thanks for the advice.
Cheers
 

bilge

.
Mar 26, 2016
5
Catalina 309 Mooloolaba
Hi Pomp. I bought the boat from a retired engineer down the Gold Coast who had added a multitude of accessories including a block arrangement for hoisting the inflatable dinghy and storing it out of the water. It was similar to this... http://seawisemarine.com/ We spend our sailing days mostly on traverses in the Coral Sea between Noosa and Caloundra so we didn't have a great need to have the rig permanently installed. When sailing, the dinghy was dropped down so that the bow was in the water and skipped along behind. I can search the garage for more details if you need them. Cheers
 
Apr 3, 2012
95
Catalina 309 Sydney
Thanks for info, we normally hoist ours onto fordeck, but it does get in the way a bit.
Always looking for better options.
Good luck with your polarity problem..
 

bilge

.
Mar 26, 2016
5
Catalina 309 Mooloolaba
Thanks for all your help. Turns out BigEasy spotted the problem early. Some dodgy connections in the shore power box were causing intermittent drops. All good now. Thanks shipmates.