Electrical Problem

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Charley Seaton

removehtml]I have a 1997 Hunter 336. I was dockside with dock power. I flipped on the hot water heater which runs off my AC power panel. I smelt smoke so I shut it off. I turned off all the power to the boat. Now when I try to turn on the main AC breaker and then try to turn on anything on that panel it shuts off the main AC breaker on the panel. The swith automatically goes to the off position. If anyone has any information about what might be going on it would be greatly appriciated. Error: Error: expected [/URL], but found [/removehtml] instead[/removehtml]
 
Sep 25, 2008
7,689
Alden 50 Sarasota, Florida
you need to inspect all AC wiring

from the shore power plug on the boat to the panel and then to the water heater. Somewhere along the path you will most likely see burned insulation indicating a short or badly corroded connection. If you have a multimeter, you can probably isolate the problem by looking for a low impedence reading along the way indicative of a short. You may not look at it this way right now but consider yourself lucky you noticed the problem before it escalated.
 
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Charley Seaton

Thank you for the advice. I figured that might be the problem. Why would that cause the AC breaker switch to go off when ever I turn the a breaker on to another AC appliance?
 

CalebD

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Jun 27, 2006
1,479
Tartan 27' 1967 Nyack, NY
You smelled smoke right?

So some wire insulation was burning somewhere and probably created a short in the wiring. The breaker is supposed to turn off when this happens otherwise you get a fire. As previously stated, you need to check ALL the AC wiring and maybe even replace it.
 
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Charley Seaton

Yes I did smell smoke.. Thank you for the information. I will trace out the wire and hopefully find the problem. I just wanted to make sure that could be the most likely cause... Thanks again, Charley
 

Mike B

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Apr 15, 2007
1,013
Beneteau 43 Baltimore, MD
Be safe

Charley, your post leads me to believe you're not overly familiar with electrical circuits. At the risk of insulting your intelligence; please be sure to disconnect your shore cords from any AC powersource before doing your exploratory. While I know this may seem obvious to most, it isn't to some. Just trying to be safe. Chances are you'll find some nice black soot and burned wires at the source of the problem. Since any of the AC breakers trip your main my guess would be it's in behind your AC breaker panel. Good luck with your search. Mike
 

Rick D

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Jun 14, 2008
7,204
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Also,

Since you didn't happen to be running a heater at the same time, by chance? Anyhow, I would start by looking at the shorepower socket. It isn't uncommon to have an overheating/short when your power cord and the socket leads get corroded with time. Rick D.
 
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Charley Seaton

Thank you. I am not that experienced with electrical but I will be sure to eliminate all power before I check it out.. Thanks
 
Jun 2, 2004
1,438
Oday 25 pittsburgh
It sounds like a neutral wire has melted through

All of the neutrals are connected together, as are all of the grounds. If one has burned through, and is laying on the other, as soon as you flip on a breaker, it will short right to ground and pop the breaker. If it were a hot, it would only short when that breaker was turned on. I am not 100% but I would look for a short between the neutral and the ground. It could also be a short in your shore cable. Maybe the end is loose? Borrow a cable if you don't find anything and give it a try. Like Mike said, Be careful! r.w.landau Edited: I am assuming that the main breaker is on with no individual circuit breakers are turned on.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Look First

I wouldn't spend too much time looking for a short before the onboard breaker. If I read correctly, the AC breaker on the boat is tripping. This indicates to me that it is after the breaker, not in front of it. A short anywhere in front of the breaker will not trip the breaker. Only a short on the load side of the breaker will trip it. Others are correct in looking for some burnt insulation. If you smelled smoke, then more than likely you do have some insulation burnt off. Since it did it when you turned on the water heater, this should be the first circuit checked.
 
Jun 2, 2004
1,438
Oday 25 pittsburgh
Nice N Easy, if the neutral and ground are

shorting in the cable, it will not matter until a load circuit is complete. The main breaker completes no circuits. As soon as an individual breaker is turned on, a circuit is then included, and power can complete a circuit. The circuit runs back to the source. It really could be the cable or the plug like Rick mentioned. r.w.landau Edited: Please reread #8 for a clarification. It was also edited.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
I have to disagree

rw, the neutral and ground are for all intents and purposes the same circuit on an AC system. If they are shorted together, they will kick a GFI in an instant, but should not kick a regular breaker. You can disconnect either one, and still have a working circuit. Or take an ohm meter and check between the neutral and ground circuits. No resistance, they are common. Check any breaker box, and see where these two circuits lead. If the hot and either the neutral or ground are shorted together, it will kick the breaker, but only if the breaker is on. A short in front of the breaker, should not kick the breaker.
 
Jun 2, 2004
1,438
Oday 25 pittsburgh
Nice N Easy you are right, if this is not GFI.

If the problem is after the main and common to all the circuits.... ( Have all the other breakers been tried, or just a few?) On a 120 main circuit, all the breakers are on the same bus. So, the main should blow if a neutral/ground is shorting the bus. Charley is saying that all of the circuits are being shorted but not the main, just after the main. Is the main a GFI circuit? This would justify a short to neutral when a breaker is turned on. It would also explain the main not shorting out with just the main. Is the main GFI'ed. If the main is GFI'ed on the panel,the cord or the plug could be bad. Find out if the main is GFI protected. r.w.landau
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I have read all of the posts carefully and good

advise has been given. Since the main can be set to on but then trips when any secondary breaker is turned on there is probably a pinch point that cascaded from just one short to several. I would trace all of the hot wires (black)until I found a place where they all fed thru a single hole. I once found a problem where the rust on a romex staple had penetrated the insulation on a GFCI circuit and when the humidity was high would trip the breaker. You may not find any smoke but enough heat can soften the insulation and allow wires under a strain to pull through the insulation and short. Once they make contact they will always trip the breaker. These are tough to find and often can look good but you must make certain that each conductor can move freely and is not stuck to another.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
I read a little closer

I think Ross nailed it. If the main stays on until any other breaker is turned on, and then trips, I would also think the problem should lie in the bus that feeds the other circuits from the main. rw, I never even considered that the main might be a GFI. I hate those things, particularly on a boat. They are just too sensitive. Have no quarrel with what they do, or are supposed to do, but with the humidity and moisture on a boat they are more trouble than they are worth, at least for me. I will confess that I have GFI protected receptacles in the galley and head on my boat, and don't have any particular problems with them.
 

Mike B

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Apr 15, 2007
1,013
Beneteau 43 Baltimore, MD
T-Shooting the circuit

He has multiple breakers tied into his main AC. He can turn on his main AC breaker without it tripping. Normally he should be able to turn on some of the secondary breakers without tripping the main. Once he turns on the one with the short it should trip the secondary breaker before tripping the main. In this case no matter which breaker he turns on, it trips the main breaker. So the question is, what has all the secondary breakers tied together to cause the main to trip? Obviously the question of the day. Some possibilities: The short is most likely somewhere after the secondary breakers but in the area of the breakers to cause any and all of them to trip the main. Not sure how Hunter insulates their AC terminals but it's possible that he's got something across them. Another possibility is that he has a bad connection on the back of the AC panel itself that has melted down and created a short between multiple breakers. It's also possible that a wire tied in a bundle could have gotten hot enough to melt through all of the surrounding wires thereby creating the problem he's described. If the load increases slowly, as poor connection are know to do, the current draw could have been enough to cause a melt down without tripping the breaker. This actually could have been something that was building up over time and finally burned itself through. While somewhat similiar to the above, this one will provide different symptoms. A loose connection on the shore cord can cause the cord to heat up and burn. Remember problems like this normally wont trip a breaker as the load increases gradually and doesn't provide a big enough surge to trip it. If it's going to trip a breaker it should be the one on the power post not the one in the boat. We had three seperate boaters with this problem just this past summer. None tripped breakers. Two were going up in smoke. From experience I believe he'll find the problem on the hot (black) side of the circuit. My money says he'll find the problem behind the AC panel. Mike
 
Nov 28, 2004
209
Hunter 310 San Pedro
Check the panel

Charley, The short is probably in the panel itself. Open the panel and inspect the leads from the main breaker to each buss and hot circuit. You will probably see the problem immediately. Dennis W. S/V FullSailed
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I suspect that there are two problems. after the one we have been struggling wit

will still remain the one that caused him to smell hot wiring. I am beginning to think that he has had a loose connection that was getting hot and that finally caused the cascade that now exists. I am troubled that the main breaker trips but the secondary breaker does not. Edit to add: by saying a loose connection I don't mean sloppy loose just not tight enough to make a full contact that will carry the same current as the wire.
 

Mike B

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Apr 15, 2007
1,013
Beneteau 43 Baltimore, MD
One and the same

Ross there's a very good chance they're one and the same. Once he finds the burned spot he'll find the loose connection or chafed wires. The loose connection created resistance, resistance creates heat, heat melts circuit boards, wires, connectors, etc. Find the heat and you'll find the source of the problem. Mike
 
Jun 2, 2004
1,438
Oday 25 pittsburgh
Another assumption because my last one didn't

seem right. Charley, have you checked all the breakers or just maybe 2? I don't think That all the breakers are blowing. I bet it is one or two. I think Ross probably has it right that something chafed, shorted and maybe burned through a few wires. The hot side is the side that does the most damage. Charley, let us know before you go back to the boat so that everyone can place their bets! Where is RAD on this one? This will be a neat one to see what happened! r.w.landau
 
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