Where has my shore power decided to terminate inside my Catalina '30?

[iyamwhatiyam]

My 1989 Catalina '30 has an Dometic A/C unit that we leave running when we are hooked up to the 30 amp shore power pedestal on the dock. Never had a problem until now. Came by to check on the boat and noticed that the A/C wasn't running. Although I don't remember leaving it that way, the inverter was in the ON position. If I did leave it on when I last left the boat, it was an error on my part.

I have a circuit tester for 110 AC, two orange indicators on and the red indicator off is what you want to see when plugging it into an AC receptacle. I have an adapter so I can also plug it into the 30 amp shore power at one end and the female receptor at the end where the SP cable plugs into the boat at the transom locker. I have good power all the way to the end of the shore power cable where it plugs into the boat 110 volt system.

Now, the aforementioned inverter when turned on powers the 110 volt outlets on both sides of the boat just fine, so that portion of the circuitry seems OK. Once the A/C unit starts to power up, the inverter go into overload and shuts down as expected.

I will attach some photos of the electrical panel and the Shore Power/Battery selection switches. I tested a couple of AC breakers behind the panel with a multi-meter and they both were closed when they needed to be closed and open when they needed to be open. Sorry, I don't remember how they were labeled, but they were part of the process of elimination. I did not test for current going to the switches since I had already clumsily blown a 20 amp fuse to the refrigerator by shorting the terminals of the switch with a continuity tester and I besides I was working alone.

I opened up the transom lazarette where the shore power receptacle is and saw no breaker and identified a flat white insulation carrying the wires into the boat towards the panel. I don't remember the markings except that it was highly rated for capacity, watts I think. Once I got into the panel, I saw two cables that looked identical and of course any markings were worn off. Coming off the top of the panel I traced a wire that in a roundabout way got to the AC/DC selector switch, (I think it had a connection to a terminal or two before it got to the shore power selector switch). Ah, you can see the two flat cables in the panel photo. I think the one coming from the shore power has a green wire coming down from the top of the panel where the shore power ties into the panel.

Possible Clues: It had rained heavily in between the time shore power was working and when it wasn't.
It appears I mistakenly left the inverter on while the boat was using shore power and running A/C. The inverter still works fine.
The green shore power indicator light is just slightly brighter when the selector switches are in the OFF position.

I'm a novice in matters electrical, but I have a technical IT background, and have the capacity to learn. Can someone kindly suggest some possible scenarios how this situation came about and where to go next in the trouble shooting process? Much appreciated. Thanks for slogging through my late night recollections.

[smac999]

It looks like the green shore led is on. So you should have power from the dock to that breaker.

You need to trace it with volts. , not continuity. Follow the 120ac. You’ll have it, and then not have it somewhere.

Though if you have shore power to that breaker. And the inverter works from that breaker. The issue has to be at that breaker.


Leaving the inverter on will do no harm. It will just send power to the inverter breaker which won’t be on.

Thats what the sliding lockout is for. So you can’t have both in.

[CharlieJ]

Where is the shore power inlet? If, as I recall, it is aft, it is > 10' from the panelboard and a supplemental double pole circuit breaker (DPCB) will be installed in the lazzerette.

The fact that the green power available LED is lit is good, the fact that it is dim when the breaker is closed is bad. That dimming of a low current draw LED indicates that when you close the "Shore" CB you are placing a significant load on the incoming shore power which results in a voltage drop which dims the LED.

Suggest that you check the voltage on the line side of the "Shore" CB when it is open. It should be about 120VAC. Close the "Shore" CB and recheck voltage on both line and load sides of that CB.

[gonesail]

so are you saying your A/C no longer has 120v. from the shore power? and are the 120v. outlets from shore power working or not? does the A/C have a breaker or is it hard wired? it could be the A/C is not getting enough amps to start up but you would need to check that out

[iyamwhatiyam]

@smac999, thank you for the clarity. I did not even think of checking what was going on behind the 120v source selector switch. I semi-realized that shore power was making it to the source selector due to the green shore power indicator light. The window above the panel leaks intermittently when the rain direction is just so. It's possible that water made it to the source selector. I've never unscrewed and pulled the source selector switch, so THAT is my next step. And caulking the window now and eventually replacing it has just moved way up my priority list. Again, many thanks.

[iyamwhatiyam]

@CharlieJ, thank you! As I responded to SMAC99, my next step is to pull the source selector switch and see what is going on there.


And I did check for a breaker where, (as you correctly surmised), the shore power does plug into the receptacle located at the starboard base of the transom lazerette. I could find no such thing as far as I could follow the cable going forward.

[iyamwhatiyam]

@gonesail, the A/C not running was just the first thing I noticed, so I included that in the narrative. While it will naturally overload the inverter in about 5 seconds, just running the inverter and checking all the 120v plugs, they all have power but ONLY from the inverter. The shore power gets stopped cold, no battery charger, no A/C, no outlets. Many thanks!

[Stu Jackson]

Originally Posted by CharlieJ

Where is the shore power inlet? If, as I recall, it is aft, it is > 10' from the panelboard and a supplemental double pole circuit breaker (DPCB) will be installed in the lazzerette..>>>>>>>>>>>>

Charlie,


Not necessarily. The OP said: ...1989 Catalina '30... They didn't come that way from the factory back then, unless a PO added one.

I'm a novice in matters electrical, but I have a technical IT background, and have the capacity to learn.

Great. You're on the right track. While you're in there, start drawing wiring diagrams and labeling wires.


Good luck.

[Valmika]

Scanning through the posts so sorry if I missed something. A friend has a 1989 cat 36 and had AC power issues on some of his plugs,. It turns out there was a tripped GFI plug in the aft cabin that he hadn't noticed. I don't know if Catalina installed this or maybe a PO

[ebs001]

From looking at the thumbnails, you can only have one source of power feeding the panel at a time. It is either energized from the inverter or from the shore power. There is a mechanical lock out so that you cannot have both sources on at once.

If the inverter breaker was on then you had to have left it on (or somebody else switched it). Nothing is really wrong here. Just human error.

[iyamwhatiyam]

Valmika, Yes there is a 120 plug below the panel with a GFI, I checked it and it was not tripped and all the 120 outlets work with the inverter on and the source selector for inverter in the ON position. I pulled out the 120 selector switch out of the panel and tested it for the breaker on/off function and they seem OK.

Rain was in the offing so I did not attach the shore power cable to test for voltage at the selector switch.

Question. Where and how is the best way to test for shore power at the panel? I'm thinking the hot side of the AC/inverter selector switch. With a multitester, black lead on engine block ground wire with red lead to hot side of AC/inverter selector switch? I tested the 120 AC inverter selector switch and it worked as designed for the inverter. I guess I should have used a multi tester to test my theory about black lead on engine ground cable and red lead on hot side of inverter selector switch.

Anybody agree that checking if it's hot on the input side of the AC source selector is the next test? Am I correct in testing by multi tester red lead to hot side of selector and the black lead to the engine ground cable?

[iyamwhatiyam]

Originally Posted by CharlieJ

Where is the shore power inlet? If, as I recall, it is aft, it is > 10' from the panelboard and a supplemental double pole circuit breaker (DPCB) will be installed in the lazzerette.

The fact that the green power available LED is lit is good, the fact that it is dim when the breaker is closed is bad. That dimming of a low current draw LED indicates that when you close the "Shore" CB you are placing a significant load on the incoming shore power which results in a voltage drop which dims the LED.

Suggest that you check the voltage on the line side of the "Shore" CB when it is open. It should be about 120VAC. Close the "Shore" CB and recheck voltage on both line and load sides of that CB.

Thanks Charlie, in order to do this right, (hot line side), am I correct to assume that the Red lead contacts the line side at the breaker, while the black lead is touching the ground cable to the engine? The voltage should be at the line side regardless for whether the CB is open or closed, right? Thank you!
Oh yeah, FYI - no double pole circuit in the aft lazzerette.

[iyamwhatiyam]

Originally Posted by ebs001

From looking at the thumbnails, you can only have one source of power feeding the panel at a time. It is either energized from the inverter or from the shore power. There is a mechanical lock out so that you cannot have both sources on at once.

If the inverter breaker was on then you had to have left it on (or somebody else switched it). Nothing is really wrong here. Just human error.

Dear EBS,
Good point, but not the actual problem, although I will say my understanding of the AC selector switch has grown by leaps and bounds during this exercise. Next is to find if power has made it as far as the AC source selector switch from the shore power. Always open to any suggestions about the best way to conduct this test.

[Valmika]

Question. Where and how is the best way to test for shore power at the panel? I'm thinking the hot side of the AC/inverter selector switch. With a multitester, black lead on engine block ground wire with red lead to hot side of AC/inverter selector switch? I tested the 120 AC inverter selector switch and it worked as designed for the inverter. I guess I should have used a multi tester to test my theory about black lead on engine ground cable and red lead on hot side of inverter selector switch.

Anybody agree that checking if it's hot on the input side of the AC source selector is the next test? Am I correct in testing by multi tester red lead to hot side of selector and the black lead to the engine ground cable?[/QUOTE]


Ac power (at least in houses ) will have a hot , a neutral, and a ground. The hot is usually a red wire but could also be black. the Neutral is almost always a white, and the ground is almost always a bare or green wire. You should be able to get 120 V between your hot and neutral. also you should be able to get 120V between hot and ground.

[iyamwhatiyam]

Here is a picture of my AC Source Selector hanging out of the panel, just for fun. Seems OK. However I also found a plethora of really, really "not up to code" connectors behind the panel in the meantime. I think I'll resurrect my "Rat's Nest" post for those. Stay Tuned!!!