Amp Ratings

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Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
I am installing an 800 watt generator and to do so, I am wiring in a 3 position selector switch [shore/gen/none]. First question is what ampere rating should I be looking at for this switch? Between the switch and my Freedom 20 charger/interter I am going to run a 2 pole circuit breaker. What amp rating should this be? As always, your help is both respected and appreciated.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Do you have two spare breaker postiions on your AC breaker panel?
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Afraid it's full up. Besides, as I am figuring it thus far, the hot/neutral leads from the 3 postion switch go to the circuit breaker, then to the inverter/charger, then to the ac side of the boat's existing panel box.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Another case of the "use of the available

Try the first reply here: http://c34.org/bbs/index.php/topic,833.0.html

The 8032 or 8132 switches by Blue Seas do what you need.

There also appears to be no reason to provide an additional switch between the inverter and the selector switch.

Are you going to use the output into your boat's electrical system or just use the inverter's receptacles?

Some inverters also have their own internal transfer switches. Those are usually found on combined inverter chargers.
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
I assumed the reason for the circuit breaker between the ac input selector switch [shore/gen/none] and the inverter was to protect the inverter. Are you thinking that's overkill, Stu?

I had planned to use the ac output from the inverter into the boat's existing ac power panel. The individual switches on that panel would give me some control over the devices on the boat.

I do believe the Heart Freedom 20 inverter/charger does have auto transfer.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Electrical math

800 watts at 120 volts is
P=I(amps)x V(volts)---> P/V=I --> 800/120=6.66 amps
But
you probably have a 20 amp (20x120=2400 watt) shore power service so you should breaker and wire for that. You will have a hard time finding AC three wire that will not handle a 20 amp service as that is an industry standard.
Remember the breaker protects the wire down stream from it not the device. Put a fuse in the output (probably already has one if it is a decent genset) of the genset to protect the genset from overloading.

If you have an inverter, a genset and shore power you need a 4 way switch (or equivalent) to insure that only one AC power source is connected at any given time. connecting an inverter and the genset at the same time WILL cause an expensive replacement of the inverter and possibly the genset too.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Yeah, I was wondering why you're sending AC power TO the inverter?

And why a generator that only puts out 800 watts? A Honda 1000 portable would serve you better, and you could plug it into the shore power input connector.

We assume you have 30 amp shore power?

I wouldn't use the auto transfer circuitry.
 
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Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
It's a combined Freedom inverter charger, right?

Sorry I didn't read your original post as carefully as I should have done.

If the generator is plugged into the shorepower connection the internal switch on the Freedom should suffice. You only have to worry about two different sources of AC in if there's a chance you'd be plugged into shorepower and you run the generator and the same time. Which makes no sense. Your installation has already run the incoming AC from the shorepower inlet to the I/C and only then to the boat's main AC breaker.

The Freedom has it's own internal switch.

If you operate it gen to shorepower inlet, you don't need a three position switch, because the generator simply takes the place of the shorepower and you don't need an 8132 for regular shorepower, do you? I know there are some other generator wiring arrangements in the Freedom installation manual, but I don't have them right here at the moment. IIRC, they're designed for situations where you have a generator permanently wired up and ready to go in case the utility power fails and/or you need to test your generator regularly when the mains power is still working, or to switch back when the utility power comes back on after an outage when you're running the genset. That's not usually what's happening on a boat with a generator and shorepower.

[Edited multiple times]
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Checked the manual

Richard,

I pulled the Freedom Manual I have, it's for the entire Freedom line, including your 20.

Yes, there are a number of wiring options including transfer switches to accommodate gen sets. Installation Option 2, for instance, includes a 4 kW genset and shorepower feeding the Freedom and then the AC panel. The shorepower incoming and the genset output connect to a transfer switch and then the common wiring goes to the Freedom and on to the AC panel.

But you simply don't need to do this, just plug your small genset into your shorepower inlet, since they'll never run at the same time. No costly transfer switch or rewiring is needed. Just pretend your genset is the utility company!:)

You will need an adapter/wire/pigtail to go from the genset to the shorepower connector.

You may also be interested in the "Power Sharing" feature of the Freedom charger side, if you have a Link monitor which also controls the Freedom. See: http://c34.org/bbs/index.php/topic,1474.0.html
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Of course, Stu. You are so right! It is hardly worth the substantial expense of the switch for the rare instances in which I might need to switch from shore to gen power. Thanks so much for putting me on the right path. I will simply get a pigtail to match the shore power plug on my boat, and run that from the genset as you suggest. Thanks so much for setting me straight on that, Stu. I checked on the link, and they are way over my budget. Thanks for the tip.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Glad to hear we helped

and sorry it took so long. Many of our C34 folks have generators and you can read about them using the search engine on the C34 MB. Have at it.
 
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