Carver Owners Forum

Hello, I'm looking for a definitive answer as to "best practice" for generator operation for A/C heat pumps.

Our current temporary moorage only allows a single 30amp connection, so we have been forgoing the A/C heat pumps, all three, and just using an efficient ceramic heater in main salon. we'r moving in January to a Marina w/50amp service.

I have read numerous posts here, along with the PDF Owners manual (we're fist time Carver Yacht owners, recently acquired) but i'm still confused If I can "safely" run 110V shore power on one panel and simultaneously run generator to run all three A/C units without issues on the other panel? The main panels switch is for AC power, but doesn't distinguish between Generator or shore power. Those "in-the-know" please advise.

What happens to the "un-used" A/C shore power cord ? is the cord "back-fed" and the connection end now "hot"? Do I need to get a cover for the shore side male end in order to "safely" to stow it under the stairs?

Thanks,
Cliff & Beth Mathison

You could easily use just the central unit to heat off of shore power and skip the aux heater. Or select one at a time as required to distribute heat if you want, just don't run all 3 at the same time. My previous 32" boat had a single 16,000 BTU unit and everything worked fine with only a single 30a shore power hookup. Look at it this way, your energy efficient heater most likely needs a 15a breaker which is what your main AC unit needs also/

As for shore power vs generator. You cannot function a combination of both. If you use the generator then shore power gets disconnected at the panel via the selector switch or sometimes automatically via an automated solenoid. Regardless of how it is done they are never combined. There is never any back feed to the exterior shore power prongs as the switching is done at the panel.

If you have two shore power inlets to the boat, why not just run your one 30 cord and split it to both inlets....that way you can portion out your power until the move, they have adaptors for just that.....done it for years....

bud37 wrote:Source of the post If you have two shore power inlets to the boat, why not just run your one 30 cord and split it to both inlets....that way you can portion out your power until the move, they have adaptors for just that.....done it for years....

we have the adapter, it trips the 'old dock" wiring, with adapter on, both panels on, but no A/C on, we have power, but as soon as we enable (1) or (3) A/C units, the shore power breaker trips. Doesn't trip with panel one only and ceramic heater, unless hot water tank on and range on at same time.
This is what led to my plugged in but running genny question.

Everything above is good info. It appears the shore power is somewhat inadequate. Glad your moving from this place I'll bet! Good Luck and I hope your new home is a better situation!
PS>I have also seen a bad neutral at the shore power supply give u tripping problems along with an inadequate amp supply at the shore power pedestal!

Cliffm wrote:Source of the post

bud37 wrote:Source of the post If you have two shore power inlets to the boat, why not just run your one 30 cord and split it to both inlets....that way you can portion out your power until the move, they have adaptors for just that.....done it for years....

we have the adapter, it trips the 'old dock" wiring, with adapter on, both panels on, but no A/C on, we have power, but as soon as we enable (1) or (3) A/C units, the shore power breaker trips. Doesn't trip with panel one only and ceramic heater, unless hot water tank on and range on at same time.
This is what led to my plugged in but running genny question.

I guess my question is what possibly could be consuming so many amps? I know for a fact a water heater and AC not to mention charger, lights, fridge can easily run off a single 30a breaker . That being said you will get a 50a connection after the move which is only 20a more than what you have now to run 3 units. Point is something is amiss. I have a feeling your 30a shore power breaker at the pedestal is actually a 20a or the breaker is old and performing like a 20A.

I agree, something is up there, unless you have a ground fault with one appliance......but sounds to me like you are not getting all 30amps.

I'd turn the water heater breaker off and try it again with just one A/C units running. You only need the water heater to run periodically to get and keep hot water, just make sure you run it for a bit before you're ready to take a shower.

Often, it's just the compressor start-up spike that blows the breaker. Once you get past that, you could turn the water heater back on and let it run. I've thought about putting in a relay (contactor) that would disable the water heater when the A/C compressor is running as a way to run on a single 30A circuit, but still haven't implemented that.

I agree with all the above. You should also check the condition of your cord's plugs, the boat's inlets, and the shore power pedestal's outlet. Are there any signs around the contacts that they have overheated? If so, you may have a bad connection that is increasing the draw and tripping the breaker.

quick update:
moved to Elliott Bay Marina, twin 30A connections per slip. Plugged both cables in, powered up both panels, turned on all three AC units in auto mode (one at a time) took a bit but got interior up to 70F. It appears that running front stateroom blows into galley area, so we ran both aft and front stateroom AC units, with salon off and kept everything comfy and drawing only 10A.