Need electrical help

[David Barclay]

I have 1999 Carver 356 Aft cabin. When running off of the 6.5 Kohler generator, I get a serious rattling noise from the breaker panel when the cruise air or any large amp appliance is turn on. Some times the a/c will kick on and some times it flakes out. Is this a generator problem or or what I think is a relay problem in the breaker box? At yhis time my generator only want to run one cruise air. The cruise air runs at about 13 amps in 120 volts when running but at start up it jumps to like 30 amps. That is when I hear all of the racket in the breaker box. Please advise.
Thanks,
David

[Viper]

It sounds like you have an automatic switch-over from shore power to generator. That is to say that when you run your generator, it automatically switches from shore power to ship's power without you having to manually switch it over yourself. If that's the case, this is accomplished with a relay that is mounted behind the breaker panel. The racket you're hearing is probably relay chatter. Could be the relay is on it's way out, a poor connection, low supply voltage from generator (which could be due to a poor connection), etc.

[David Barclay]

IMG_1750.jpeg

This is what is making all of the noise. Is this a transfer switch??

[buster53]

Ok, I have a 356 as well. It is normal to hear the transfer switch chatter when switching over to genset or back to shore power. However, the way you describe it, boat is already on gen power and you hear the chatter when adding a big load. Am I correct on this?
I do have a bigger genset than you, but 6.5 should easily be able to power both AC units, unless you are pulling a lot of other power, maybe using the stove while the water heater is kicking in.
One thing I might suggest, when you need both AC units running, turn on the bigger one first and then the aft unit second. Reason for that, the smaller unit will have a smaller electrical surge than the bigger one. With the bigger one already running, it just might work.

[David Barclay]

You are correct I am on gen e power when I am hearing this chatter. I can only run one a/c at best. When the a/c kicks in I can see the amp meter really jump high and there is a bunch of chatter from the panel. Sometimes the compressor starts and some time it flakes out but it’s not like the gen bogs down like it is over loaded. Just not sure if I have a gen power problem or transfer switch that is causing my inability to run the two a/c units. By the way, this boat is new to me..

[km1125]

You should be able to tell if your water heater is drawing current or not by how many amps are on the meter. If it's drawing current while you're experiencing the chatter issue, you can cut that breaker off. No one will know if the water heater is off for five or ten minutes, as the water will still be hot.

I've often thought about putting in a contactor in the water heater circuit, so that if the range or big A/C compressor is on it cuts the water heater off automatically during that time.

[buster53]

Sounds like a good time to call in a marine electrician.

[David Barclay]

Just trying to ask questions before I try to find a marine electrician. Just thought with this huge forum and as old as this boat is that someone might have experienced this situation before.

[Viper]

Source of the post

IMG_1750.jpeg

This is what is making all of the noise. Is this a transfer switch??

Yes that is the transfer switch I was referring to. Check the connections, and check the output voltage when the generator is running, especially when a heavy load kicks in. If the voltage drops considerably, that might be your problem. Again, that might be the result of poor/loose/corroded connections, bad relay (transfer switch), or poor generator output which could be due to a few things. Also check the surfaces of the contacts on the relay. If they are corroded or burnt, you'll have the same symptoms.

[bud37]

In my boat the transfer switch was only heard when the gen was switched on if I remember right.......once running stable there was no more noise except for the rpm during load changes.

Is it right to assume you are away from the dock power ?

A/C equipment etc gets old and may be drawing too much power on start up .......

The marine electrician sounds like a good idea to me as these things are very hard to diagnose in a forum setting unless someone has had the exact same occurrences.