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Old 07-16-2015, 03:49 PM   #1
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Air conditioner 110 wiring.

Ahoy!
I was hoping someone could provide a schematic that shows the power supply to our two 16k marine AC units. I have two 30 amp inlets- and I need to see what components are necessary to switch back and forth from shore power and generator. Thanks for any help.
steve (at) forkliftt.com


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Old 07-16-2015, 05:22 PM   #2
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I have some diagrams for our '86 38' Present, but they are on the boat. How do you currently switch from shore to generator? We have one A/C unit on each 30 amp leg. There are two transfer switches "Shore Off Generator".
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Old 07-16-2015, 10:53 PM   #3
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That is pretty basic boat wiring 101. If you are not sure at this stage what to do, you should call in a professional.

As noted, you need a transfer switch that feeds the A/Cs off either one of your 30a cords or the genset. Before and after the switch you should have the proper breakers.
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Old 07-17-2015, 07:03 AM   #4
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"I have two 30 amp inlets- and I need to see what components are necessary to switch back and forth from shore power and generator"

It is probably built in already.

On the master AC panel there should be ganged circuit breakers.

Set up with a guard so only ONE source (power pole or noisemaker) can feed at one time.

NO extra switch , they both are connected to the boats wiring at the same time , you just cant power with both at the same toime.

KISS , cheap and foolproof , till you add an inverter !!
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Old 07-17-2015, 11:56 PM   #5
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Quote:
Originally Posted by BobH View Post
I have some diagrams for our '86 38' Present, but they are on the boat. How do you currently switch from shore to generator? We have one A/C unit on each 30 amp leg. There are two transfer switches "Shore Off Generator".

Thanks All.
Bob- current setup as received is a Gen/Shore Power switch. Feeds an AC/DC breaker box.
I guess my first step is to document how what I have operates now.
Cause after the breaker box- I have a hand labeled Shore/ Gen "light switch" that use to to have to be flipped along with 3 switches attend on at the lower helm labeled Main, front and rear.
We operate both units at the slip fine, but am unable to get either AC unit to run on the generator. Hopefully I can get a copy of your schematic Bob.


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Old 07-20-2015, 05:57 PM   #6
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Any chance someone onboard has a double 30 amp in/ dual AC with a generator schematic???


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Old 07-20-2015, 06:14 PM   #7
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I won't be on the boat till next week. If both units work on shore power they should also work if you switch the selector to Gen unless somebody wired them directly to the shore power inlet rather than the main panel which should be after the transfer switch. Are the breakers for the A/C units on the same panel as all the other AC loads?


On our boat the forward A/C is the only load on one of the 30 amp feeds, but that feed is switched through a second Shore/Gen transfer switch. This was an afterthought since the original setup only had one A/C unit so I think the second 30 amp shore power and transfer switch were added when the second A/C unit was added.


On our last, and wish we still had it, sailboat, there was one transfer switch which switched both 30 amp circuits. I think it was a six pole switch to transfer the hot, neutral and ground wires.


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Old 07-20-2015, 06:33 PM   #8
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I suspect that the schematics I have won't be of much help. It almost sounds like the wiring was done by a PO, like our second A/C unit, and the only way to figure out how it is wired is to get down and dirty and trace the wires.


I couldn't believe some of the wiring on our sailboat, a '84 model. Some of it I had to stop and sit back and say to myself, now somebody did this intentionally, but it makes absolutely no sense, what am I missing. They had run a wire from battery plus to the hot connection of the starter which was wired to the output connection of the battery switch so no matter what position the battery switch was in, A, B or Off, the DC circuits where always hot. Totally off the topic but the point is, that with an older boat POs may have done some strange things.


So unplug shore power, get a flashlight, open up panels and trace wiring. May require two people, one to wiggle the cable at one end and the other one to see which one moves at the other end.


Kinda sounds like fun, especially in the summer with the A/C off.


Bob
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Old 07-20-2015, 06:37 PM   #9
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Thanks Bob- gonna execute the plan


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