Yeah my wires from shore power plug to main breaker are 12/3. So i should replace that wire with 10/3 and sounds like my outlet will be just fine with 12/3
AC Wiring Question
- Thread starter tym2
- Start date
Thank you for the welcome. You do not start derating wire untill you get over 100 ft. 12Gage is ratted at 25 amps. Do not exceed the limits of your plug device ( 20 amp) by using a higher capacity breaker. Safety first above all other considerations. Always consider startup draw on all your devices. That is why you use a 25 amp rated wire for a 20 amp circuit. 14 Gage wire is rated at 20 amps but can only be used for 15 amp continues draw.
When you are changing out the wire from the shore plug to the breaker panel make sure that you also change the jumbers from the main breaker to the sub-panel breakers. Here is a photo of the 12ga jumpers on my 88 C30.
They are what tipped me off to the 12ga problem.
When I found these two wires I was loading the boat to head out on a two week cruise. Instead I used that "free time" to completely rewire the AC side of the electrical system.
I find your ratings to be very interesting. Unfortunately, all I have to go by are the National Electrical Code (NEC) ratings and ABYC ratings but obviously you have something which is much more in depth. I think all of us could benefit from your resources if you could be good enough to share. Thanks.
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Another consideration is control of circuits. It is convenient to be able to turn devices on or off from a single location. For example, it would be convenient to be able to turn the fridge off without affecting the battery charger. This is usually accomplished with a circuit breaker panel. Suggest that you install a small, say, six circuit 120 Volt panel with separate breakers and wiring for your appliances. Portable devices, such as cell phone chargers, hair dryers and the like are best served with conveniently placed GFCI receptacles. Appliances such as the fridge or the battery charger are best served with dedicated circuits. Most boats have the 120 Volt breakers next to the 12 Volt breakers in two separate groupings.
I agree. From my non-switched fuse block, I have a lead from the hot side to a breaker switch that is for the fridge. The breaker is mounted to the
DC side of the panel. That way, I can leave it on or turn if off without needing to have the main panel hot. The other things on the non-switched fuse block are items that are never switched (bilge pumps, station preset for AM/FM radio, hydronic heater power). The hydronic heater is a safety thing. It has two DC inputs, (power and control). The control is switched, and the power is unswitched per the Espar instructions. That way if the main battery switch is turned off while the heater is operating, the control will go dead and put the heater into cool down. The "power" line will stay live to allow the heater to go through its cool down cycle. Otherwise, you could do a hot shutdown which is harmful to the unit and potentially dangerous due to heat buildup.
I have 3 which works for me. Charger, water heater, outlest. If you have AC that would add one. That is all that I can think of for my C30 size but bigger boats might want a couple of outlet breakers and possibly two AC's which would get to 6.
To the OP, I'm a little late to this party as I don't normally read the Catalina forum. After skimming through the posts here it seems pretty clear that there is some confusion about sound electrical practices on a boat. A good place to start learning about marine electrical systems, which are different from shore based electrical systems would be Charlie Wing's book, Boatowner's Illustrated Electrical Guide (Amazon Link).
Done correctly, electrical systems are safe, done incorrectly they are deadly.
Done correctly, electrical systems are safe, done incorrectly they are deadly.
op doesn't really need the redundancy of 120 and 12 volts for the refrigeration unit.
Contrary to what everybody thinks, the start load on those little units is very low on startup (put a amp meter on them sometime and you'll see what I mean) most people don't have a DC amp meter which makes all these discussions speculative
going by name plates can be misleading as most of us assume as name plate information means FULL LOAD AMPS very few appliances run on FLA.
The onboard battery charger is usually on 24/7 when you're on Shore power which is the way many or most cruising boats are set up for. I learned this on my own because I come from the old school when battery chargers pretty
much destroyed a batteries if you left them connected lol
Usually larger equipment like central air, ice makers, air compressors, have a name plate that reads FLA, RA, LRA (locked rotor amps) required voltage and recommended breaker size
Contrary to what everybody thinks, the start load on those little units is very low on startup (put a amp meter on them sometime and you'll see what I mean) most people don't have a DC amp meter which makes all these discussions speculative
going by name plates can be misleading as most of us assume as name plate information means FULL LOAD AMPS very few appliances run on FLA.
The onboard battery charger is usually on 24/7 when you're on Shore power which is the way many or most cruising boats are set up for. I learned this on my own because I come from the old school when battery chargers pretty
much destroyed a batteries if you left them connected lol
Usually larger equipment like central air, ice makers, air compressors, have a name plate that reads FLA, RA, LRA (locked rotor amps) required voltage and recommended breaker size
I have 4 on my boat…for some reason my outlet’s are split between fwd and aft outlets. According to my original oday manual, outlets were on a single breaker.
I don’t have A/C at this point.
Greg