Installing AC, need the best source for electric power.-gctid816865

[Hyperlite]

So I am installing 16K BTU Air Conditioner unit in Ciera 2855. I have a switch panel and i am wondering what would be the best to use to supply 110V to the unit since it will have a pretty substantial draw.

Could I just use the outlet that supplies 110 V around the boat? Will the breaker for it be sufficient?

[The_Other_Gary]

In a word, no. Your present house panel 30amp will need power for your water heater, fridge, battery charger and outlets. A 16000btu AC needs to be fused at 25 amps minimum to handle the start loads plus the cooling pump. You need to add a second 30amp inlet and separate 30 amp panel for the AC.

If this is an issue you can add a 25 amp breaker to your present panel but you will need to shut off your water heater at a minimum when using the AC as it will draw 23 amps at every start cycle. Ideally it should be two breakers, 20amp for the AC and 5amp for the cooling pump.

This gets old real fast when you forget and plug in a toaster or kettle and the breaker pops.

You also run the risk of a cord overheat and possible electrical fire. New boats with AC always have a separate second inlet

[Hyperlite]

Thanks! Here is the thing, I have only used water heater once, in October, 2 years ago when i lived on the boat for the experience of living on the boat I do not have a toaster. I rarely use a stove, almost never, and i will unlikely to use them simultaneously. Only thing is i might use a kettle now and then, but again, rarely and i will remember to turn off the AC.

I won't be installing a second outlet, I only have one 30 AMP access, and the only thing that will be running with the AC is the battery charger, that draws almost nothing.

So should i still add another breaker to the panel? Would i connect the cables directly to the shore power, where it goes to the switchboard, add a breaker and use the recommended 12 Ga power cables?

[The_Other_Gary]

Add a 25 amp breaker which will take power from the buss bar and wire with 12ga or even 10 ga marine wire making sure you do all the proper connections to the neutral bar and grounding bar. Your panel should have several blanks to add breakers. If not, get a small breaker panel to piggyback making sure you attach the wiring to the existing buss bars, not to the inlet wires.

If your panel is stock and no extra outlets have been added you should have a spare like the bottom blankout marked accessory.

[Hyperlite]

Actually mine does not. I have exactly the same switch panel, however the accessories one already has a switch in it. Now that i think about it, i have no idea what the accessories one does, i doubt i have ever used it. I have no idea what it has been wired to.

I think what i will do is just change whatever now in the accessories to run the AC, make sure it is wired properly from the buss bars and use a 25AMP breaker and 10 Ga wires.

Thanks so much, i really appreciate your advise! That makes a lot more sense now.

[Jeffw]

Where do you live/boat? My 2858 has more cubic feet to cool than a 2855, and the standard AC from the factory was 12k btu. My boat came without AC, but it now has a 16k unit for our climate, currently 114*F, and it is adequate. At the So. Calif. coast, it is way more than needed. The point of this is if you are in a moderate climate, 12k will be fine, plus use less power, and will probably run on a 2000 watt generator away from the dock if desired. A 16k will not.

[itsabowtime2]

Having installed AC now on 2 boats here is my experience.

1) You will not need a second 30 amp service. I have run my AC, TV and microwave simultaneously without issue. And yes I strongly considered running the dedicated 2nd service the first time around, had the parts to do it, but found it not necessary. Battery chargers (2 on the current boat) also on.

2) Use ONLY marine grade wiring.

3) Get a water pump larger than what you believe you will need. I learned this the hard way an had to switch my first install to a March AC5.

4) Install a simple T fitting with a hose connection. Great to have if you happen to lose prime at the dock. I got mine at a local auto parts store for $5.00.

Plan on several more hours than you suspect for the project. It is really straight forward but the time it takes to route everything just right, take apart and put back together everything you disassemble in the cabin. Mine averaged 12-14 hours each.

[Hyperlite]

I do not live aboard, so this is just for the occasional nights on the boat , on the islands and all that. I already bought a 16K Btu and i will not be running it of the generator and i don't even have one

itsabowtime2:

Thanks! That is basically what i am doing, i already installed everything except for the proper wiring to the switch panel yet, just testing it through the range outlet for now. The pump requirement for the 16K Btu is 300 GPH and i will be putting 360 GPH pump , so that should do. I did the metal T-connection to the head, put a strainer, double clamped everything, and the waterflow is very good to the pump. Im in Toronto, so the water does not get crazy hot in Lake Ontario. Unfortunately i bought a used pump that was overheating, i guess due to its age almost immediately, it kept shutting down all the time, until i figured out that it was the pump, so i returned that and ordered a brand new March pump, i think 20% more water flow then required should be fine. Other than that the install was pretty straight forward.

One question though, manufacturer recommends 20Amp breaker for the AC and i already have a 15Amp breaker in the accessories panel, i am contemplating just using that and see if that would work.

[Jeffw]

One question though, manufacturer recommends 20Amp breaker for the AC and i already have a 15Amp breaker in the accessories panel, i am contemplating just using that and see if that would work.

It will probably work, until something goes wrong. Use the 20 amp.

[Hyperlite]

Good point thanks

Yeah, i will order a 20 apm one