Shore power problem

[Bill Root]

Tonight I lost the shore power at the panel and can't get it to come back on. My 54MY has the shore power set-up that is common to most all the early to late 80's 53' and over motor yachts: two 50A/240V and one 50A/125V inlet connector on eaqch side of the boat near the pilot house doors, and a main 12v switching panel next to the pilot house helm station. I'm still getting used to this system, since my 43 had a much simpler set-up.

I have only 50A/240V at the dock, so I have only one power cord connected. The panel shows a red light above 240V #3. Normally I'm pretty careful about how much load I put on the system at one time, but tonight it was quite cold, so in addition to the refrigerator, TV and lights I had two AC pumps, two AC units and the water heater going at the same time when the everything went down. The transformer circuit breaker did not trip. I toggled it on and off with no effect. The red light above the black master switch was out. However, when I turned the master switch from source 3 to off, the 240V light came on which would seem to indicate power coming to the panel, but there was no power to the breakers or meters on the panel.

Next I tried moving the shore power cord from connector #2 to connector #1Same thing. The 240V light #1 above the master dial switch would come on when the switch was in the off position, but went out as soon as I moved it to the #1 position. I changed all four fuses, but that didn't help. It was too dark outside to mess around with a multi-meter, so we packed up and went home. Before leaving I ran the generator. The panel powered up and evrything ran fine. What am I missing here? My owner's manual is no help.

Sorry for the long post. I'm hoping one of you "night owls" will have the answer before I head back to the boat tomorrow morning.

 

[Bill Root]

Please excuse typo in the previous message. Of course the electrical distribution panel next to the pilot house helm station is 120V, not 12v.

 

[saltshaker]

Check the master GFI breaker

 

[Bill Root]

Any idea where I would find that?

 

[saltshaker]

I'm going by memory here. I don't have that system but my friends 60C does and he had the same issue. I believe it is a white breaker on the main panel or check the panels in the ER. Hope this helps. Does the panel energize from the generator?

 

[Bill Root]

The panel does energize from the generator. I ran the generator before I left the boat and it powered up the panel just fine. I'll check the engine room to see if any breakers are tripped or fuses blown, but I don't recall seeing anything down there that would cause this kind of problem. Thanks for the tip.

 

[True Grit]

Check the outlet as well in the ER. I had a bad GFI outlet and it presented a similar set of symptoms

 

[davidwigler]

Did you check the breakers on the shorepower box? After that, walk down the dock toward the shore and look for another breaker box for multiple slips. In my case, it was that breaker box where the breaker had tripped.

 

[saltshaker]

Did you check the breakers on the shorepower box? After that, walk down the dock toward the shore and look for another breaker box for multiple slips. In my case, it was that breaker box where the breaker had tripped.

OOPS guess it was late last night. Definitely start there. Make sure you have power at the pedestal before going through the boat.

 

[Bill Root]

Thanks again for the ideas. I'm headed back to the boat this morning. Hopefully I can figure this out in the daylight. However, the fact that the #3 red light on the panel that is supposed to be indicating that power is coming into the boat on shore line is on has me confused. That should mean that I have power from the dock, shouldn't it?
And why would that light be on when the black dial switch at the top of the panel is in the off position, but go out as soon as the dial is turned to select #3?

 

[Capndan]

Try running your shore cable to the inlet on the other side of the boat. I had a similar problem and it ended up being corrosion in the recepticals that showed up under high loads. If your fuses got hot that would indicate a similar problem. You'll get a light but as soon as you put on a load you'll lose the connection. Make sure your fuses are tight after they are in. The springs that keep them tight can be weakened from the heat created from the poor connection.
If it works with the genny I would think it has to be the shore panel or outward.

 

[MikeP]

From your description I'd guess you have a panel set-up like this:

The GFI breakers are the white ones in the panels. BUT if you have genny power to everything, they cannot be tripped off since if they were, genny power would not be present at any device/outlet either.

If you have a red light showing with shore power connected then, as you said, there IS power there from shore and the breaker at the marina box/meter must also be on. However, it is possible that you have insufficient shore power which is causing the light to go off when a load is applied or, as suggested in the previous post, that there is some internal connection issue at the shore power cable panel. But it seems very unlikely to me that the same poor-connection issue would exist on both sides.



I would check the voltage at the marina box to see that you are getting around 120VAC between each hot and neutral. And then do the same check at the boat-end of the cable you are using. If both checks show 120 off each/240 of of both, then the problem has to be in the panels or something common to both panels.

You probably have 2 transformers, so when you switch the cable from one shore cable panel to the other, you are switching transformers as well. Again, seems extremely unlikely that both transformers are acting up.

Maybe a bad neutral could cause the problem since it is common to both.

It will be interesting to hear what the problem was.

 

[REBrueckner]

(I'm not familiar with your specific electrical set up....)

First, are the red lamps for voltage or reverse polarity???
Second, while making various checks, have you turned off all you loads except for say a light to test for the presenceof power?
Post #11 sounds like a possibility.

I'd suggest you pull out the electrical circuit diagram for your 120/240 volt electrical systems and begin trouble shooting from that. And check to see if any "Bubba" has made (pencil) changes to the diagram while you are at it.

If you get normal power from your genny but not from a shore power selection, then that will enable you to begin isolating the problem: what components are in the shorepower circuit(s) NOT in the genny circuit? Apparently the genny circuit and its components work properly.

Seems like a key indicator is your statement:

"...when I turned the master switch from source 3 to off, the 240V light came on which would seem to indicate power coming to the panel, but there was no power to the breakers or meters on the panel."

Anyone able to diagnose why this would happen?

When you changed all four fuses, did you check for voltage at those fuses??? Are those fuses in the shore power circuit ONLY or BOTH shore and genny power circuits?? Be sure to rotate fuses in their holders to scrape off oxidation and make a good contact....

edit: while composing, I see Mike P posted....good advice there...I concluded as did Mike that if any source works, here the genny, then it's not likely a GFCI issue. What I am unsure about is if all the GFCI are 120 volt....if so, that would mean neutral aboard is ok because the GFCI monitors for equal currents between hot and neutral. If the GFCI's have not tripped that signals the current in the 120 volt hot and neutral legs are equal...that is, normal.

 

[Bill Root]

Mike:

Thanks for your input. My panel looks different from yours, but the general idea is the same. On mine the left side of the panel has all the power source selection stuff and meters. The right side has all the individual breakers for each circuit on the boat, broken down into two groups, distribution panel 1 and distribution panel two. On the source side (left), basic set-up is a master gen/shore switch, breakers for transformer one & two, and breakers for source one and two. There are dial switches at the top to select which line to take the power from, and dial switches at the bottom to select which line each of the two distribution panels will take it's power from. The three red lights at the top of the source side of the panel show which shore line connection the power is comming from, one light for each of the two 240V and one for the 125V.

Rob:

Thanks for your input. It's beginning to sound to me like your idea that there may be just enough power coming into the boat to illuminate the light, but not enough to carry a load makes sense. I'm going to start by searching for breakers on the dock, then I'll test for power at the boat end of my shore power cord to see if I have 120 comming out of each leg. If so, then I'll move on to the fuses. It was very dark last night when I changed them, so maybe I didn't get them in correctly. If that doesn't solve the problem I'll try moving the power cord to the other side of the boat.

Unfortunately I don't have e-mail access on the boat at this time. I'll let you all know how I made out when I get home.

 

[jim rosenthal]

Bill, you might try using a digital VOM at the dockside receptacle, and also inspect the ends of the cable to see if the high load burned the plug on either end, which happens frequently. You can also use the digital VOM to "ring back" the cable conductors one by one to see if any of them are not passing current. Essentially what you have to do is verify the integrity of the entire current path, beginning with the dockside breakers, the pedestal, the cable ends, the cable conductors, the inlet on the boat itself, etc. From my experience, the weak points in the system tend to be where things join, and the pedestal and the inlet on the boat are among the frequent failure points. Good luck and let us know what you find.

 

[GJH]

I had virtually the same symptoms once and it turned out one leg on the pedestal was bad. Still, with all the loads you had, two 50's coming in will serve you much better.

 

[spcoolin]

I had virtually the same symptoms once and it turned out one leg on the pedestal was bad. Still, with all the loads you had, two 50's coming in will serve you much better.

I agree...Many shore breakers that have two toggles tied together externally (Double Pole Double Throw as opposed to Double Pole Single Throw one toggle) will not show tripped, if only one leg (toggle) tripped...

The light might light with only one leg applied but when load is applied the voltage drops...

Cycle the shore breakers by turning them off & back on...If that fixes the problem, then restart the loads you had on that night & look at your amp meters...One side/leg could be overloaded, or if it trips again at less than the breaker's one side/leg rating it is likely the breaker on shore has grown weak and the marina should replace it...
You can also feel that breaker for heat with your finger on the face of it...If it gets hot...Same thing, it's weak, or overloaded, but an amp meter will provide the answer of which it is.
If it shows overloaded on that leg...You know that you can't run those same items together without another shore cord connected, and then splitting up the load with the selector switches.

Steve~

 

[rsmith]

I've seen the neon bulbs lit even when there is no power. Some kind of backfeed off the neutral. Mine you can unscrew the red lense and replace the neon bulb. Are there any led's large enough to replace the old neons? I used to trouble shoot large industrial control systems and found the digital volt meters somtimes would lie and show volts there that when the circuit was put under load were actualy dead. I use a solonoid ac tester like a SqD wiggle meter on Ideal Voltcon They actualy put enough load on the system to verify that power is actualy there.

 

[SKYCHENEY]

First off, Bill's boat does not have the GFI breakers on the main panel like the late 70's/early 80's boats have. So, that is not the issue here.

Assuming he has the breakers set right for the the source that he is plugged into, I'd guess that the problem is that only one leg has power(as was previously suggested). Check the end of the cord with a multimeter and proceed from there. If the isolation transformer does not get both legs, you will get zero power unless it is switched to 120v input and you have a 120v cord hooked up.

 

[Bill Root]

Problem solved yesterday. As was suggested by Rob, Sky and others, the problem was that a circuit breaker way up the dock that controlled one leg of the 240V line had tripped. The single 120V leg coming into the boat was sufficient to power the red shore power indicator light as long as there was no load on it. As soon as the selector switch on the main panel was turned to that line and a load was placed on it, the light would go out. Once I found the breaker on the dock and reset it, the full 240V power came back on.

Our boat sits by itself at the marina's old fuel dock, which has only 30A power. To get 50A power to our boat, the marina folks combined two separate 30A lines with a common ground. This arrangement was new to me. Whenever i had hooked to 50A in the opast, it had been from a single 50A power stand with one breaker, so I didn't realize that there were actually two separate breakers for my set-up until you guys mentioned it.

Up until Friday 50A has been sufficient for us since we don't live on the boat and are on it only a couple of days each week. 50A has always worked fine as long as we don't try to run all five AC units, the range, MCWV and coffee maker at the same time. Apparently there was some unusually large draw Friday night that shut evrything down.

Thanks to everyone who offered advice. Now at least I know where the dock breakers are and can find them in the dark. I guess folks are right when they say it takes a year to fully understand the systems on a new boat when it's as complicated as these 50+ footers are.