T&T: Blow Fuse on Gulfstar 38MC and Amp Question

[Peter Bennett]

I think that more information, particularly numbers, is required
before anyone can make useful suggestions.

What current did you measure on shore power before the fuse blew?
What current did you measure while using the generator?
What current is required by the water heater alone, and by the ceramic
heater alone?
Was there anything else (like a battery charger, perhaps) that may
have been using AC?

Although ABYC now requires circuit breakers rather than fuses in AC
circuits, I'm guessing that the fuse carries all incoming shore
power.  If your shore power inlet is the common 30 amp twistlock
connector, I would expect a 30 amp fuse there, unless the boat wiring
is designed for 20 amp.


Saturday, January 5, 2008, 8:53:03 PM, Roy wrote:

RH> I have a Gulfstar 38MC which has a fuse next to the shore power
RH> cord connection on the boat.  Tonight
RH> while doing some work on the boat, connected to shore power, I
RH> turned on the water heater then a while
RH> later turned on a small heater in the boat.  The amps jumped up
RH> then shortly after the fuse blew at the
RH> shore power connection.  The fuse is a BUSS one time use NON-20 amp.  

RH> After I blew the fuse I cranked up the gen set and turned on the
RH> same items, water heater and small
RH> ceramic heater.  With the same items turned on the amp draw did
RH> not jump up like it did when I was
RH> connected to shore power.  I was very careful to load the gen set
RH> with the same draw as the shore power
RH> and did see the amps move up when turning on both the water
RH> heater and ceramic heater, but not to the
RH> extent it did earlier.   The water heater was not on long enough
RH> to fully heat up, so it should have
RH> been drawing the same amps and the ceramic heater was on the same
RH> setting.  No other items were on.

RH> Any idea why the draw on amps would be more when connected to
RH> shore power?  Could I have a problem with
RH> the power coming from the dock connection?  Seems like the draw
RH> would be the same connected to shore or
RH> the gen set providing power.  

RH> Thanks
RH> Roy
RH> m/v Knot At Work
RH> New Iberia, LA

RH> Roy Holleman
RH> New Iberia, LA
RH> Office 337-896-9115
RH> Office Direct 337-896-5824
RH> Cell 337-258-3110

-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca