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Shore power circuits

2K views 11 replies 9 participants last post by  mitiempo 
#1 ·
Hi All,

The good ship has 5 AC wall outlets installed for shore power... all on the same breaker. I have (2) spares on the AC panel. One of those is going to be dedicated microwave. I'm contemplating splitting up the existing 5 outlets into 2 breakers. We can't run the heater and make coffee at the same time.

Secondly... I was pondering a GFI outlet into the AC wiring. Does anyone have one of those, where or why not?

Dave
 
#4 ·
I like the dedicated microwave circuit to come from the inverter.that way you can heat old coffee when unplugged. If you have two separate circuits to wall plugs (15 amps each) and blow a breaker It's in the panel. Heater alone probably pulls 15 amps so not much left on that line. Other line can run coffee maker or hot plate etc. but not both If you blow a breaker now it's on the dock at 30 amps?? A few trips out into the rain will train you to be prudent.No charging inverter? Forget my first comment.
 
#5 ·
I prefer each outlet to be on its own circuit. That way the only breaker you are likely to blow will be the one on the dock. I have 3 outlets usable plus one dedicated to the microwave and all are GFI's. My other circuits are for the battery charger and a hardwired baseboard heater with thermostat.

I do not understand why even some larger boats often have all the outlets on one or two breakers.
 
#6 ·
I'm not clear on the value of separate circuits for each outlet.

Auspicious has port (8 outlets) and starboard (4 outlets) circuits, a water heater circuit, and a battery charger outlet on the main 30A inlet. The A/C 30A inlet has forward and aft A/C unit circuits and an A/C circ pump circuit plus an independent electric heater outlet.
 
#8 ·
I'm not clear on the value of separate circuits for each outlet.

Auspicious has port (8 outlets) and starboard (4 outlets) circuits, a water heater circuit, and a battery charger outlet on the main 30A inlet. The A/C 30A inlet has forward and aft A/C unit circuits and an A/C circ pump circuit plus an independent electric heater outlet.
Because if you string 3 outlets on a single, 15 amp branch breaker, you can only run a cumulative 15 amps on all of the outlets. That means you can only run a single 1500w heater, and basically the other two outlets are useless because there is no spare capacity on the 15 amp breaker.

I only have 3 outlets on my 30 foot boat, but they are all on separate 15 amp branch circuits, and since they are all individual and not daisy-chained, they are ALL GFCI outlets. This gives me the ability to pull 30 full amps from at least two outlets and not trip the mains breaker.

Caveat:

Please understand that when I say "15 amps" and "30 amps" I'm not including the 20% safety buffer that you're supposed to build into your circuits. You're only supposed to pull 24 continuous amps through your 30 amp mains breaker and 12 continuous amps through a 15 amp branch circuit breaker.

I'm sure that Auspicious knows this, but for readers who are contemplating installing shore power, or new liveaboards, the 20% safety buffer is important to avoid wiring meltdowns that won't trip the circuit breakers. This is referred to as "boiling the frog".
 
#7 ·
ABYC "AC and DC Electrical Systems On Boats" Standard E-11 requires any outlet in installed in a head, galley, machinery space or weather deck be a Type A G.F.C.I.

but I agree with eherlihy that all outlets on a boat should be G.F.C.I. protected.
 
#12 ·
ABYC "AC and DC Electrical Systems On Boats" Standard E-11 requires any outlet in installed in a head, galley, machinery space or weather deck be a Type A G.F.C.I.

but I agree with eherlihy that all outlets on a boat should be G.F.C.I. protected.
I agree also. In a smaller boat any area can be damp - probably more so than the bathroom in a house.
 
#10 ·
IIRC the codes call for one GFI to be installed as close to the dock power inlet as possible. And if you've got more than one GFI daisy-chained in the same lines, they can cause each other to trip out for no real reason. So, one GFI, as close to the dock power as possible, should be the simplest and best solution. IIRC.
 
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