[C38] shore power

[Chuck Finn]

Patrick,
Our main breaker is 30 amps, but this can be very misleading.  This is a 
30 amp breaker, which feeds the two, 117-20 volt, 15 amp breakers.  
There are two, 117 volt circuits in our boats.  Usually, your battery 
charger and everything else is on one and your water heater is on the 
other.  The water heaters we commonly have are 1500 watt, which pretty 
much maxes out the one circuit breaker.  So, you get the other 15 amps 
to work with.  Now, you might think that gives you  15 x 120=1800 watts 
available, but is really about a max of 1500 watts  (80-90% of max is 
considered relatively safe).   So, now you can add things up:

microwave:   600 - 1000 watts.
hair dryer: 400 - 1000 watts.

What makes me write this is the wire outlet that melted.  This I believe 
is the "load" wire and the melting on the plug looks more like an 
"arcing" issue.  I think  Steve S. and Tom T. are better at this than I 
am, but there are two ways I know we get arc melting.   First is not 
shutting off your circuit breakers before unplugging, but I am guessing 
you do this.  Second is the problem caused by cords getting stretched as 
the boat moves on the dock.  I see this a lot at the marinas I visit.  
Folks simply plug their boats in like they would a vacuum cleaner at 
home, with no attempt to secure the plug.  Yes, there are cords that 
have a threaded coupler, but I cannot see that yours is one.  
Regardless, I have a rule that both ends of my electrical cord have a 
"wrap" around some secure point on my boat and the dock (I use the large 
winch).  I believe many marinas want you to take a wrap around the the 
power pedestal to protect their outlets and this is a rule at my yacht 
club.  Steve S. has an article all about this by the way!

Boat US reports this is a major issue regarding insurance fires on 
boats.  Perhaps we should be discussing this as well?

Chuck Finn
Mighty Quinn  #114
Great Lakes


On 6/6/2011 1:51 PM, Patrick Harpole wrote:
> A few days ago I asked for help determining loss of shore power.  
> Thanks for
> the advice.  Turns out one terminal of the female connector to Marinco 
> cable
> melted down.  Local hardware sold connector for about $20.  Works fine.
> Harbor Freight sells (about $20)device which plugs into wall then plug
> appliance into other end.  It reads power consumed by appliance.  I 
> believe
> I was using too many amps, for example, hairdryer.
> Patrick
> "Blue Eyes"
>
>
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