Auto Transfer Switch

[ngriffin]

Hello all. New Member. Have had a used 1993 330 mariner for a year now. Been dealing with an issue with power on the outlet side of my system. I have 2 30 amp inlets, one for ac and one for the receptacles and appliances. I apparently have some sort of automatic transfer switch/solenoid that takes it from shore to generator automatically. I've done some troubleshooting and process of elimination, but I'm not an electrician, I'm trying to knock out the obvious stuff. The power inlets feed into a carver junction box behind the wall that appears to meet up with the generator power input as well as the interior boat wiring to the AC and the other circuit for receptacles, appliances etc. I have power all day on both systems when on generator, however when on shore power I only have power on the air conditioning side. So far I've replaced the shore power inlet, bypassed (temporarily) the 30 amp inlet breaker for that leg, and still have no power at all when on shore power. So I'm leaning towards something either in that junction box, or behind the electrical panel where all my ac and dc switches are. Any tips? Thanks all!

[km1125]

Yes, there are relays (or "contactors" in there somewhere. I've heard the are behind the panel and likely in that junction box you are describing. There are two of these, one for each shore power inlet. They are activated when you are on generator power, and they switch both inlets to connect to the generator. When the generator is not running, they should pass through power from the actual inlet to the main breakers. Sounds like one of yours is bad and not making the connection on the shore power side, or a connector inside there has gone bad.

[ngriffin]

Yes, thank you. after a bit more digging I've determined the box is an automatic transfer switch, similar to the one here.

https://www.defender.com/product3.jsp?p ... id=1832843

This one only shows a single shore power 30amp inlet, I have 2. Any ideas? Thanks

[bud37]

Welcome to the forum......could you make a small drawing of how it is wired or a pic showing where and how the shore #1 and shore#2 are connected to this device......is it possible this shore #2 circuit was added with the gen to the original boat???......

[ngriffin]

Pretty bad diagram, but you'll get the idea. The Airconditiong side is just fine. Tested all the way through the cables/y adapter, problem appears to be at the ATS.

Power.jpg

[bud37]

Not bad..would be nice to see how the wiring is inside the transfer switch.....first thing, it is possible the isolator could be wired incorrectly according to your drawing.....two circuits get two isolators or one designed for two circuits.....get the manufacturers name and model # and google the install instructions to check as to the model for two inlets as opposed to one. It should be isolated in the green wires , everything in one side and everything out the other. Maybe a reference issue, But please check install instructions first, one thing at a time.Perhaps there are two terminals on either end for each branch, double check...

To add, all energy from the gen will stay in the boat when it is running, but on shore power you should have ground reference back to the pole.
I will also add that my understanding of this is pretty basic at best.

[ngriffin]

I agree, I'm not sure the isolater is hooked up correctly either. That being said, I've bypassed it and passed the grounds direct on through to the transfer switch, still had the same issue.

[ngriffin]

I believe its setup like the dual 30 here:
https://www.yandina.com/acrobats/GalvOwnManual.pdf

[bud37]

Okay then, bummer....I think for someone to help further we need to see the inside of that magic box, if possible.


You can see though in that schematic that all green goes in one side then out the other, thus creating a way for the diodes to work.....anyhow.. like I said one step at a time.

[ngriffin]

Both Green Grounds from the inlet plugs go to one lead (bad drawing i guess), and then the other side of the isolator green connects to the grounds of the cords that feed into the transfer switch. This is probably a better representation.

Power.jpg