Shore power not working

Up Ships Creek

New Member
Oct 8, 2017
13
Brick NJ On the Barnegat Bay
Boat Info
1985 Sea Ray 270 DA
Engines
Twin 170 hp 4 cylinder mercs alpha 1 drives
Hello everyone, new member here. I just bought a 1985 270 DA my first boat and I will probably have alot of questions along the way. The boat is on the hard and needs some repairs. I bought a 30 amp adapter to plug into the yard power but it's not working. When I plug it in and turn on the main switch it go's right off. The volt meter does not register and when I push the test switch the reversed polarity light on comes on. There are no engine batteries but there is another one, not sure if it's charged did not bring a volt meter. That's about it don't know if I left anything out, if you need more information just let me know.
 
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Sounds like bad shore power cord, or drawing more amps than the outlet you are plugged into. Check both ends of you cable, make sure no signs of burning
 
Im using a 100 foot 12 gauge extension cord, that's the closest outlet to me, with a 30 amp marinco power cord plus adapter. The 12 gauge cord is in good shape I use it all the time. I thought that's what I was supposed to use.
 
When I plug it in and turn on the main switch it go's right off.
What do you mean "it go's right off"? So did it come on for an instance? Not sure about your model, but there may be a breaker near where your shore power plugs in... make sure it's on.
 
What do you mean "it go's right off"?
When I flip the main toggle on the electronic panel to the on position it goes right back to the off position. the shore power plugs in right where the panel is. I thought the main toggle was the breaker. This is all new to me so be patient. I'm a carpenter by trade, not very good at electrical.
 
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There is a good chance you have a short/disconnected wire somewhere in the shore power inlet circuit. I say that because I went through the same thing this year. Suddenly our air conditioning unit turned off and the panel lit up with reverse polarity and was showing ~50v (120v line)

I took apart the shore power connection which on our boat is inside the lazarette on a bulkhead and subject to moisture. Turns out, the neutral wire had all but disintegrated from corrosion but was making just enough contact to feed the panel with what appeared to be 50v. Once I moved it, the wire fell apart. It also had burned the shore power cord and the shore power inlet.

disconnect all shore power and power down the AC side (turning off battery switces can't hurt either for safety sake) and inspect the shore power inlet area including the wires behind it. You may find you need to splice in new wires or replace the inlet all together.

Also, ff you have any hesitation after inspecting the wiring this might be a job for a qualified electrician, it's a very important system on your boat and needs to be done correctly to ensure safety of you and the boat.
 
Thanks for the info. The shore power inlet is on the port side right where the bow rail starts and the panel is right there as you walk down into the cabin. As I was connecting to the inlet it was a little loose. I guess if I unscrew the panel and look behind it I should see where the inlet attaches. I don't have ac and do not know where the battery switch is, would assume it's in the engine compartment. This is all new to me. Have alot to learn. Thanks.
 
As you can tell can't sleep tonight, on the boat and have alot running through my head. Was thinking if the battery switch was already off would that make a difference?
 
So if it kicks right back off, that is a breaker and you have a fault/short there somewhere. Like Ryan posted, start at the shore input panel.

The battery switch position should not make any difference with this problem.
 
I was under the assumption you needed a 10 gauge extension cord for a 30 amp circuit. I also think your 100' run is too long and you're not getting the 110v at the panel.
 
I was under the assumption you needed a 10 gauge extension cord for a 30 amp circuit. I also think your 100' run is too long and you're not getting the 110v at the panel.
You are correct on the 10AWG... if you are going to actually draw 30A. At this point he is just trying to get 110VAC to his panel. 100 feet of 12AWG cable with no load, will still be 110VAC. Now once he finds why his main breaker won't set and fixes that, loading it will start to drop that voltage.

And there is a good question for the OP... Do you have all of the other breakers off? Like for air conditioner, hot water and such?
 
Chasing electrical shorts can lead you down a lot of rabbit holes. So start with the easy stuff before you start unscrewing things. Like is the power good at the post? Did you try plugging something else into it or test it with a meter? Did you try a different shore power cord? Etc.
 
You are correct on the 10AWG... if you are going to actually draw 30A. At this point he is just trying to get 110VAC to his panel. 100 feet of 12AWG cable with no load, will still be 110VAC. Now once he finds why his main breaker won't set and fixes that, loading it will start to drop that voltage.

And there is a good question for the OP... Do you have all of the other breakers off? Like for air conditioner, hot water and such?
there is a good question for the OP... Do you have all of the other breakers off? Like for air conditioner, hot water and such?
The post where I plug into work's fine I use it all the time. All the other breakers are off. I've used other cords for sanders, heat gun and radio, all work fine. I'll take the panel off and take a look. So should I get a 10 gauge cord once the issue is fixed?
 
So should I get a 10 gauge cord once the issue is fixed?
If you're just running a battery charger and some lights while the boat is on the hard, your 12AWG may be OK. When in your slip and running air/hot water/etc... then yes, 10AWG required.
 
I had a similar issue, and the prongs on the plug needed to be stretched out a bit to make better contact. Loose connection will trip the reverse polarity
 
I had a similar issue, and the prongs on the plug needed to be stretched out a bit to make better contact. Loose connection will trip the reverse polarity
I noticed that when I plugged in the adapter the male plug on the boat was loose. If I remove the panel from the wall it should give access to the plug, right. Maybe a new plug. I'll stop what I'm doing now and take a look.
 
Ok, I looked at the plug outside and it is indeed broken, the inside plastic around the plug is 3/4 broken away so will need a new one. Then pulled the breaker box away from the wall and all the wires seem to be in good shape, but found three mud wasp nests so pulled them out and cleaned it up in there. Then I pulled the cover off the breaker box to inspect the wires in there and everything looks to be in order. Could not fine any corrosion maybe where the wires connect to the plug, guess I'll remove that next.
 
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If its the marinco inlet our local west marine had rebuild kits and all the parts. Depending whats broken you can get away with just the insert, seal, etc. Not sure what they were using in '85 though
 
It's a marine industries company at least that's what the cover says. Anyway it's going to have to wait, the screws are spinning have to hold the nuts on the inside. Here by myself today will have help tomorrow. Maybe the adapter is not going on all the way and just pushing it back, lets hope. Anyway after I have an extra set of hands tomorrow I'll pull it off and see and continue then will let you know. Thank you everyone for all your help it is really appreciated. Now back to removing the boot stripes. Thanks again.
 
Make sure to inspect the wires that connect to that Inlet closely when you get it out of there to make sure none are black (burnt). If there is a problem you may be able to cut back to clean copper and still have enough slack, if not, then you’ll need to run a new one from the inlet to your breaker panel. Not sure about the layout on your 270, but it was a fairly short run that was easily accessible on my old 300 Sundancer once I got the inlet out.
Also, give the adapter you’re using a good look too to make sure there is no sign of a burnt spot on the female end that connects to the inlet on your boat.
 

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