can two a/c units be run on a 30 amp shore

[shadowdancer]

I've got two a/c units forward (16) and an aft (9) can they both be run on thirty amp shore plug. ?

thanks
rock

[S/V Illusion]

Why not simply look at the current draw ratings clearly stated on your A/C units to see if they add up to 30 amps? Every brand A/C unit can be searched on the internet if you can’t find the rating label on the unit.

[Wood]

I can run 2 16K and 1 12K on 25 amps. Soft start separately.

[sailorboy1]

Originally Posted by shadowdancer

I've got two a/c units forward (16) and an aft (9) can they both be run on thirty amp shore plug. ?

thanks
rock

yes

I'm doing it right now. I do have an EasyStart on the 16k and a hard start kit on the smaller. If you try to run anything else you are asking for a trip (including a battery charger if the battery is low)

[a64pilot]

Originally Posted by Wood

I can run 2 16K and 1 12K on 25 amps. Soft start separately.

That is hard to believe, you must have some very efficient AC’s
Average current draw with water pump for a 16K is 11 amps at 120V thats running of course, not start up.
What brand of units do you have? Your not 220V by any chance are you?

I run a 16 and a 6 and with the charger, lights, TV’s Engle etc I average about 22 amps

[Group9]

Our boat runs three A/C units on one 30 amp service. But, that’s all it handles. We never try to start all three at once, in fact most of the time we only run two of them. I can’t remember the BTUs, but they cool a 42 aft cabin, two stateroom and salon, power boat.

[motion30]

I have one 12000btu unit and 1 16000btu unit that runs off one 30 amp circut

[Denallan]

I run a 16 and a 9 (I think) on one 30 amp,but they are the only things on that circuit.Batt charger,water heater,110v outlets are on a seperate shore power circuit.

[valhalla360]

The big trick is getting them started. It can take 2-3 times the rated amps to get the compressor to turn over. Soft start systems help a lot with this.

After that, you better keep a close eye on the cords and plugs to make sure they aren't overheating and the terminals are clean and bright to get a good connection. Very easy to burn up a plug pulling that much.

[redneckrob]

Originally Posted by valhalla360

The big trick is getting them started. It can take 2-3 times the rated amps to get the compressor to turn over. Soft start systems help a lot with this.

After that, you better keep a close eye on the cords and plugs to make sure they aren't overheating and the terminals are clean and bright to get a good connection. Very easy to burn up a plug pulling that much.

There are also a number of inverters that will provide a momentary current boost for start, my Xantrex is configured that way. You just need a slower tripping CB, much like you need on the entry end of an isolation transformer so that momentary overcurent doesn't trip the breaker.

[OS2Dude]

We had to add a separate 30 amp service for our A/C. (I wish we could have afforded to change to 220 service.) Otherwise the water heater, fridge, cooler, fans, battery charger, and A/C would always trip the main breaker if the shore power went out (like during a storm). Otherwise it was very rare for the breaker to trip during day-to-day usage. The A/C unit has a 30 amp breaker unto itself.

[meirriba]

Originally Posted by shadowdancer

I've got two a/c units forward (16) and an aft (9) can they both be run on thirty amp shore plug. ?

thanks
rock

Easily.
We can operate 4 units (of 14k each) on 32A

[a64pilot]

I think possibly we are seeing some European 220 boats with theses numbers cause of course with roughly twice the voltage, they pull roughly half the amps.

[Captain Bill]

It may work, but I have burned up a couple of shore connectors doing it for long periods. I have the twist lock kind which are not really all that good. The "smart-plug" connectors are supposed to be better at handling high current loads.

[valhalla360]

Originally Posted by a64pilot

I think possibly we are seeing some European 220 boats with theses numbers cause of course with roughly twice the voltage, they pull roughly half the amps.

OP: This is what you are likely seeing when people are saying they run 3 or 4 air/con units on 30amp.

220v/30amp is roughly equal to 110v/60amp, so not relevant to your situation.

Your two big considerations are:
- How to handle the startup amperage which is much higher but only for a second or so.
- Making sure you don't burn up a plug pushing it to the limits for long periods of time.