AC breaker tripping

[sailorboy1]

I tried to run my AC for the first time the other day off my portable 2200W generator and the panel breaker tripped. On the attached diagram

Bus B supplies the Air Conditioning and I had the generator connected to the Shore Power Outlet 2

On the load breakers:
The 25A breaker is for the forward AC
The next 15A is for the Aft AC
The next 10A is for the seawater pump

With the air conditioner off, the generator running, I had power to Bus B. I shut the Bus B breaker (trip pack) and the 10A relay breaker and everything was fine. But if I shut the breaker for either the forward or aft air conditioner the Bus B trip breaker would trip (the air conditioners were off). I never saw any amps display on the Bus B amp meter.

I have never run the air conditioners the past 5 years.

The generator runs things on Bus A if plugged into that bus just fine.

I'm thinking the problem is the Bus B breaker. I don't understand why it doesn't trip with the Relay breaker shut, but maybe that doesn't even power up till the air conditioner signals it.

Any other thoughts? What is a "Trippack Breaker" anyway?

Thanks

[David M]

Get a clamp ammeter and set it on peak load. What does it tell you when you turn on the AC?

[sailorboy1]

Can not turn on the air conditioning as the Bus B breaker trips within a couple seconds of shutting the breaker for either air con fed or aft. The Bus B is 30 amp and others are 25 & 15, which makes think the problem is the Bus B breaker


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[Bill Seal]

Going back some 50-60 years to my USCG ET school and all my years in electronics, I'm stumped by that diagram. Why is the shore power INLET (guzinta) labeled as OUTLET (guzouta)?
Going back to your problem, if removing load -turning OFF a breaker causes an other breaker to trip, I would suspect something in the reverse polarity protection or GFI circuits. Did you use a WYE cable?, if so, the hot wires might be crossed.

[sailorboy1]

Wires don't suddenly get crossed after 15 years


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[Sailmonkey]

Swap your buss a and buss b breakers and see if the problem persists.


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[Dsanduril]

You have a generator that can marginally put out 18A @ 120V (2200/120). Based on your forward AC breaker size the AC will never run on that generator.

The aft AC might run depending on the startup draw and the generator's surge capacity.

If you haven't run the AC in 5 years there's every chance that the compressor rotors are locked. Might be able to free them with a good dose of shore power, but not with a marginal generator.

Is there an off switch at the AC? Or way to disconnect cleanly? I would try turning off the AC, then closing the breakers. If the breakers stay closed then the problem would be in the AC units. My suspicion is that the AC starting loads are too high for your generator, the voltage drops, the current goes up, and the breaker trips. If you don't have a clamp on ammeter, then using a decent voltmeter you should be able to watch the voltage as you turn on the AC, how low does it drop?

[Bill Seal]

"But if I shut the breaker for either the forward or aft air conditioner."


I guess I misinterpreted "shut" to mean "turned off" as in "shut off the lights".or "shut down the engine


Maybe I'm getting too picky, but when the builder doesn't know the difference between INLET and OUTLET, things could get dangerous, as in getting a 220 volt to 110 volt step down transformer connected backwards, giving 440 volts out.

[sailorboy1]

Gee, never mind. Never even tired to start the air cons


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[DeepFrz]

To answer your question on the CB it is a Tri Pack cct. breaker. Only one trip lever for the three outputs I do believe. I'm not sure if the one you have is a current limiting cct. breaker or not. Expensive if it is.

Does anything else work on Bus B? I can't make out the writing on the last three 15 amp breakers. If they are plugs can you plug a toaster or something in to check if they pop the main breaker? The fact that either Fwd. or Aft. Air Con. breakers trip the main breaker probably rule out wiring issues and as you suspect point to the main breaker. However the Air Cons. may still be trying to power up or they may be trying to power up the pump. If it is the pump then that 10 amp brkr. should trip but one never knows for sure. Check the wiring and ensure that there is no way the compressors could actually be trying to activate.

Hope this helps.

[sailorboy1]

There isn't anything other than the 2 AC breakers and the relay breaker on Bus B.

I think I'll just replace the Bus B breaker. It is the biggest breaker in the circuit other than the shore power connection. I know for a fact that the generator will trip first if overloaded so the only thing that really makes sense in my mind is a bad breaker


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[sailorboy1]

I've spent a couple of hours looking at the diagram and in looking up the breaker spec. Near as I call tell is that the trip part of the Bus B supply breaker trips at 65VAC. I haven't figured out if that is a capacitor or a resistor between the trip breaker and the neutral leg of the 120V supply.

But no matter what I can not see what effect closing one of the air conditioning breakers should have on the main VAC Bus B breaker. The only thing I can see that doing would be to trip on the 30 FLA, yet the smaller air conditioning breaker or the even smaller breaker at the generator should trip first (and I know the internal generator breaker will trip).

[sailorboy1]

No one? I could take the trip part of the main Bus B VAC out by not connecting it. That still would leave the current protection.

[Cap Erict3]

Connect an extension cord straight from gen to aircon for testing


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Looking for another pretty place to work on the boat.

[sailorboy1]

Originally Posted by sailorboy1

No one? I could take the trip part of the main Bus B VAC out by not connecting it. That still would leave the current protection.

In case someone searches for a similar problem (because everyone searches for answers before starting a new thread):

I did replace the breaker and the new one did the same thing. I took off the trip wire that goes between the hot and common terminals and it stopped tripping. Near as I can tell the trip wire has a little capacitor in it and if it charges up to the discharge point the discharge current trips the Trip Pak main breaker. The setup is to trip the breaker if there is current between hot and common. I think the inverter generator (Honda 2000 type) is really hot on both the hot and common side so using something like this plugged into my boats shore power connection causes it to trip. I don't know why it doesn't trip on the other bus and assume it is because all those loads are different than the air conditioning.