AC shore power problem, any electric gurus out there?

[psychotiller]

I'm having an issue with our AC shore power on our 2004 SunFast 32i, hoping someone could point me in the right direction before I give up and call an electrician   While installing a battery isolator system I was using a jigsaw plugged into the GFI outlet on the boat to install a new battery switch.  Everything was working fine, had used the saw for a few minutes, no problems.  When I tried to use the saw again, it didn't work. I reset the main breaker on the boat, the one just after where the shore power plugs into the boat.  We were able to get AC power again to other devices, but every time I tried to use the saw it shut off again.  At this point none of the AC shore power system seems to be working.  The AC indicator light on the electric panel flickers on and off, or is either dim, or not on at all.  A few things we've tried so far include resetting the GFI, switching the AC power switch at the main panel on and off, plugging into our neighbors shore power outlet, using a different shore power cord and resetting the breaker on the dock of the Marina but to no avail.  Also, the main breaker never seems to be actually tripped, though initially resetting it seemed to help.

My next thought was maybe the main boat breaker is bad, or maybe there is another fuse or breaker hiding somewhere else I didn't find?  Is there a breaker or fuse in the electric panel I missed?  Any thoughts or suggestions?

Thanks in advance!

[royhb]

Do you suppose it's possible that the jigsaw actually has a ground fault?  Perhaps intermittently?

[psychotiller]

"Do you suppose it's possible that the jigsaw actually has a ground fault? Perhaps intermittently?"

Thanks for the suggestion! Hmm, maybe its the jigsaw?  I have just enough electrical knowledge to get myself into trouble  So having said that, the jigsaw cord is only 2 prong, no ground and the jigsaw works fine back at home.  The Boat AC system doesn't work at all anymore regardless of what we plug into it, even with the jigsaw completely disconnected.  Would that rule out something with the saw?  Or is it still a suspect?

I did have the 12V battery system unhooked from the boat while I was using the AC system for the saw.  Thus I'm assuming there was no way the two ground systems could cross over, but maybe that prevented the AC ground from working properly?  I dunno, very confused at this point.  As I mentioned, I have enough electrical knowledge to get myself into problems like this, but not enough to get out.  It always seems so simple at the start eh?  just trying to get a few good electrons from point A to point B.  What could possibly go wrong?

[MartyB]

The saw may have a fault in it, that blew the main switch or equal in the boat. While the home AC will not blow up, the boat possibly being weaker per say, was not able to handle the short with in the saw motor.

That would be my swag on this, then again, I am about a smart with AC as my dog!

Marty

[adoyabn]

When I took delivery of my SO43 back in 2003, the main circuit breaker (the one closest to the shore power connector) did fail. A replacement breaker was shipped to me under warranty and I replaced it myself. Yes, they do go bad!  I have a 110V system.

The quickest way to tell if you main breaker is bad or not is to (or have someone) is to take a voltage check on the load side of the breaker with it closed (on).

As I stated before I have a 110V system. All my GFI outlets have a test and reset button on them. I'm not sure how many GFI outlets you have on your boat (I had three that were OEM). Normally outlets are daisy chained. If you have another GFI outlet that is tripped and haven't reset it, this may be a contribuiting factor to your problem.  

Another issue that I did have is on the non GFI single AC outlets. They weren't really designed to handle a full 15 amps. I had a microwave plugged into a single non GFI receptacle. The receptacle pretty much burned up after a couple of months worth of use. I've since replaced all of the single non GFI receptacles on the boat.  If you have the original receptacle, you may want to pull them out and inspect them.

[psychotiller]

Thanks for all the great advice, looks like I have some investigating to do.  In retrospect, not sure why I didn't use the multimeter to test before and after each part of the circuit, that makes a whole lot of sense.  Better late than never I suppose.  I'll let you know what I find, hopefully it's a quick fix and requires parts readily available at West Marine.

Thanks again! If anyone else has any other advice feel free to chime in, I need all the help I can get!

[kenlewis40]

If you still have French plugs on your boat there is every chance you are using an adapter to run AC equipment. I think you will find and others may put me right, the poles are now reversed. In other words the positive is going through your equipment before tripping the breaker which is not a good idea as any shock will hit you before the breaker. If your jigsaw is at fault, it may cause your AC to react oddly.

I bought a three pin AC tester, the type with fault lights on the front. When I plugged it into my adapter I had reverse pole fault lights show up. 
I made short extensions lead for my OS32 only and reversed the pole. The AC tester now shows no faults.

I am now in the middle of changing mine to UK plugs.

Hope that helps.
Ken

[adoyabn]

Ken,

You may have done this already, If you haven't please check your source for a polarity reversal. It's not unusual to have a polarity reversal in the Marina's wiring.

Back to the original problem with the drill not working properly. If your source has a polarity reversal, this could cause your problem.

If we are talking US 110V on most modern two prong plugs, the smaller of the two is Hot and the Larger of the two is neutral.

For US 110V (30 amp Marinco) the wiring color code is Black for Hot, White for Neutral, and Green for Ground

[Trevor]

Sometimes when some breakers trip they do not look like they have tripped. Go to the main inlet breaker on the boat and switch it off and back on again. Do the same with the shore power breaker on the dock. Go to the switch panel in the boat and make sure the outlets are switched on.

As the jigsaw is double insulated and has no earth reference, polarity reversal should not make any difference.

Check with a multimeter where the voltage stops from the dock through to the outlets and somewhere you will find the discontinutity.

Regards,

[psychotiller]

Many thanks to all the great suggestions!  Heading out to the boat tomorrow to try and locate the problem child of the circuit.  I'm hoping it's something easily accessible and readily available.

Thanks again, I'll keep you posted as to what I find...or don't find.   

[psychotiller]

The good news is I was able to fix my AC power issue.  However I have absolutely no idea what I did...or didn't do. Wish I could impart some words of wisdom as to how to fix it if anyone else ever has this problem. But since I'm still not sure what I did to fix it that will be difficult 

At first I did all the same stuff as last time, reset the boat breaker and the dock breaker, still nothing. Then I tested the voltage before and after the main breaker which was good, then opened up the electric panel and started searching around. There seems to be a distribution panel in there with connectors I've never seen before.  Since I only have a limited amount of DIY electrical experience it very well could be that I've just never run across them before, but I'm wondering if it's something commonly used in Europe  (btw, I'm in California).  Anyway after wrestling in tight enclosed places with a large intimidating cluster of wires I took apart this distribution panel and started testing resistance/continuity. I figured that would be more safe than trying to use the volt meter in a tight enclosed place with way too many wires running all over the place. But I still couldn't find the problem child.  I put the panel half way back together and plugged in the AC power. Then ever so carefully I started probing around with the volt meter.  I was really concerned because it would have been way too easy to accidentally arc something since it was so tight and then I would have had a whole other headache to deal with.  Anyway, still couldn't find the problem, voltage seemed to be going everywhere it was supposed to. Then I checked the outlets again and all of the sudden they were working. Been working fine all day. Also checked for reversed polarity which I did not find.  Not sure what it was, maybe a loose connection? Maybe somehow overloading it with the jigsaw and vacuum the other day somehow loosened something?  Seems unlikely but who knows.  None of the connections seems corroded either. What I do know is I picked up a 30 amp to 15 amp adaptor for the shore power outlet so I can hook up a household extension cord directly to the marina power and will definitely be using that if I ever need to use power tools again.

Thanks so much for all of the suggestions, I pretty much did everything everyone suggested.  So one of you, or maybe all of you were right, but still not sure exactly what I did to fix it.  But as the saying goes, "Never look a gift horse in the mouth".

Thanks again for all the help everyone provided!

[dilligaf]

I would suggest that you reopen the panel and check all connections insuring they are tight. You might have a loose wire connection and before too long it may heat and cause fire OR fail completely. Good luck

[psychotiller]

I would suggest that you reopen the panel and check all connections insuring they are tight. You might have a loose wire connection and before too long it may heat and cause fire OR fail completely. Good luck

Thanks for the suggestion.  It's definitely possible there is a bad connection somewhere I missed or can't get to but none that I found when searching through the panel.  I did end up putting in a new GFI outlet as it appeared to have a little corrosion.  Although the GFI previously tested ok, from prior painful experience working on my house I know GFI's can cause all kinds of mysterious problems.  Since then I haven't had any problems.  We've been using an AC heater all night long when we stay on the boat without problems too.  

I also wonder if the problem is partly caused by the wires just getting older. This would be similar to the extremely common problem on many Yanmar starting circuits. They work fine at first but apparently after a few years of aging and general corrosion the wiring picks up more resistance and eventually leads to starting problems.  I had this issue too and the mechanic suggested putting in a start relay and since then the engine has started perfectly every time.  There were no obvious corroded or loose connections on the start circuit either.  The other option he suggested for the start circuit was to add a larger diameter wire for that circuit but the start relay was by far the path of least resistance.