Dedicated power for A/C

Crazy Dave Condon · Jul 22, 2012

I assume you are talking about air conditioning. You are correct that most boats with ac have their own dedicated line.

The intial startup of the compressor takes alot of power and with anything else on the circut in use will adversly affect the system. Then you have to be careful not to turn on alot of shore power items as it could affect the compressor shutting it down. Hope that helps.

Bill Roosa · Jul 22, 2012

A couple of things to consider; You can only run it at the dock unless you want to run a pretty big genset (do you have room for that too?) at the same time while away from the dock, the dedicated circuit is going to take some panel space, do you have that? do you have the space for the air ducts and AC circulating pump and a thru hull for same?
Honestly, I seriously doubt that a 33' boat has room for all that stuff.
I have found that 12 volt fans are a great alternative. Also consider sunshades for the foredeck and cabin. these drop my temp on a sunny day @95F to around 85 F and let me keep the ports open when it is raining to let some breeze in.
I'd recommend one of those portable units that mounts in the Vee birth hatch. had one and it worked pretty good. Then it went into the storage shed when we left the dock.

kloudie1 · Jul 22, 2012

Thaeni, I run a 12000 BTU built in unit in my 34 from one circuit of the existing 30 ampere AC breaker panel. I did not add another inlet. At my home dock, the shore circuit is good enough (has enough capacity, and good connections) that the breaker does not trip even if the 115V water heater is on at the same time as the compressor starts up. As Bill notes, installing the ductwork and the unit itself is a challenge .. I have been at docks where the water heater could not be on at the same time as the air conditioner.. but that is not a hard decision to make !

seadaddler · Jul 23, 2012

1 LINE ok

You will be OK with 1 shore power for AC as long as you don't draw too much while running the AC like some thing big like water heater and also depends how good of a good dock hookup is and all your cables from boat to dock also.
I don't use my 2 shore power hook ups I just use one for running AC but don't use the water heater at same time but other smaller things is OK if the dock line is a good 30 or 50 amp hookup.
Once I was using both AC in my motor home both kept poping the breaker but 1 AC and ref on gas and microwave was OK so it's all about hom much you try drawing from the dock hookup and what amps they have.
Most older boats only have 1 line anyway and bigger may have 3 .
Nick

JST123 · Jul 25, 2012

Have a 33.5 myself with 12K BTU airconditioning. No need to install a dedicated A/C circut. Added mine to the port A/C wiring. installed the unit under the chart table and ran the ducting up and down the port side. One duct on the bulkhead aft of the chart table routing it form the closet on the aft side. Added another in the head that can be pointed into the cabin or head this on located on the forward vanity bulkhead. It is routed from the port locker in the vberth. I have a t at the top as it exits the top onf the locker,, one goes to the one just mentioned on the forward vanity bulhead, the other part of the T going forward into the vberth. All three vents have the adjustable vents. Works well, got to the boat on Sat and it was 107 inside took a little while but it got nice in no time.

Dan Johnson · Jul 26, 2012

Same set-up...

as Kloudie with a 12k reverse cycle unit, using the bottom 120 volt breaker on the panel and a single shore power cord. Can't power up the water heater at the same time as the A/C or will get breaker trips.

Running the A/C on fan only for about 15 minutes while the water heater is on will generate plenty of hot water.

JST123 · Jul 27, 2012

Good point Dan, that is true with my installation also. But when it's 105 outside, I'm not really to worried about the hotwater. Mother nature is taking care of that.