Ahoy Paul, Ron, Marin &  List,

The following explanation was sent to the list a few weeks  ago, I have
included it for you.

Here is a brief explanation that I  received from Marinco when this happen
to me on my trawler.  The first  thing to happen was the rotary selector
switch the determines which source power  feeds the boat, Shore -  Gen-set -
"Off, "melted" in the Shore  position.  The power cord connection to the boat
had black  connections as you indicated.

The problem we face on a boat for supply  power is that by definition, we
violate the rule of 'Ohms Law' by providing a  removable cable that just
relies on a tension contact connection.

When the power company supplies the 4  Wire (Red - Green - White - Black
conductors) 200 amp service to a home,  that cable, of the correct circular
mil area, is individually striped of the  insulation, inserted in the proper
connector contained in the power buss, and  TIGHTENED, to make an absolute
positive connection.

The power cord used on a boat from the  docks pedestal to the boat
receptacle, relies on just the "wiping action" of the  contact areas to "clean" the
surface and the tension of the contacts to  maintain a positive connection.

We have a few forces working  against us trying to supply 125 volts - 30
amps, single phase  Alternating Current for our boats without a hand-wrenched
connection.  When this contact resistance increases due to  contamination,
it caused the contacts to "heat" up , which in turn caused more
contamination, which makes additional heat, this cycle continues until the ends  melt
as you indicated.

We had a small fire at our marina on a  boat that the fire Marshall
indicated that air condition power cord became so  'Hot" that it caused the wood
panel holding the power receptacle reach it's  flash point but the "30 amp
breaker at the pedestal never  tripped."

My weekly power cord maintenance  procedure is to power down the boat, use
both the CRC circuit cleaner along with  an Emory board & fine crocus cloth
to clean the contacts on both ends  of your power cords.  You might ask you
dock master to have an electrician  to inspection the contacts at the
pedestals, especially if your pedestal  is a distance from the main power source.

Joe Guarino

Tuesday, October 5, 2010, 5:23:34 PM, Trawler336 wrote:

Tac> Ahoy Paul, Ron, Marin &  List,
Tac>
Tac>
Tac> The following explanation was sent to the list a few weeks  ago, I have
Tac> included it for you.

Tac> My weekly power cord maintenance  procedure is to power down the boat,
use
Tac> both the CRC circuit cleaner along with  an Emory board & fine crocus
cloth
Tac> to clean the contacts on both ends  of your power cords.  You might ask
you
Tac> dock master to have an electrician  to inspection the contacts at the
Tac> pedestals, especially if your pedestal  is a distance from the main power
source.
Tac>
Tac> ***************
Tac>
Tac> Joe Guarino

I very strongly recommend against using emery board on the female
contacts, as it will tend to spread the spring-loaded contact parts.
The female contacts must embrace the male contacts firmly to make a
good contact.

I'm also reluctant to use any abrasive on either male or female
contacts, as they may be plated with a corrosion-resistant material,
and any abrasive will tend to remove that plating.  A contact cleaning
spray, or LPS or T-9, along with insertion/removal and rotation of the
connectors should provide sufficient cleaning effect.  If it doesn't,
the connectors should be replaced.

--
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

This made me LOL!  I'm wondering if anyone else saw the humor?

You might ask you
ock master to have an electrician  to inspection the contacts at the
edestals, especially if your pedestal  is a distance from the main power
ource.

Bob Horne, FU Hwat - San XXXXXXXX,  Ca.

-----Original Message-----
From: Trawler336@aol.com
To: trawlers-and-trawlering@lists.samurai.com
Sent: Tue, Oct 5, 2010 5:23 pm
Subject: Re: T&T: Electric Plug

Ahoy Paul, Ron, Marin &  List,

he following explanation was sent to the list a few weeks  ago, I have
ncluded it for you.

ere is a brief explanation that I  received from Marinco when this happen
o me on my trawler.  The first  thing to happen was the rotary selector
witch the determines which source power  feeds the boat, Shore -  Gen-set -
Off, "melted" in the Shore  position.  The power cord connection to the boat
ad black  connections as you indicated.

he problem we face on a boat for supply  power is that by definition, we
iolate the rule of 'Ohms Law' by providing a  removable cable that just
elies on a tension contact connection.

hen the power company supplies the 4  Wire (Red - Green - White - Black
onductors) 200 amp service to a home,  that cable, of the correct circular
il area, is individually striped of the  insulation, inserted in the proper
onnector contained in the power buss, and  TIGHTENED, to make an absolute
ositive connection.

he power cord used on a boat from the  docks pedestal to the boat
eceptacle, relies on just the "wiping action" of the  contact areas to "clean"
he
urface and the tension of the contacts to  maintain a positive connection.

e have a few forces working  against us trying to supply 125 volts - 30
mps, single phase  Alternating Current for our boats without a hand-wrenched
onnection.  When this contact resistance increases due to  contamination,
t caused the contacts to "heat" up , which in turn caused more
ontamination, which makes additional heat, this cycle continues until the ends
elt
s you indicated.

e had a small fire at our marina on a  boat that the fire Marshall
ndicated that air condition power cord became so  'Hot" that it caused the
wood
panel holding the power receptacle reach it's  flash point but the "30 amp
reaker at the pedestal never  tripped."

y weekly power cord maintenance  procedure is to power down the boat, use
oth the CRC circuit cleaner along with  an Emory board & fine crocus cloth
o clean the contacts on both ends  of your power cords.  You might ask you
ock master to have an electrician  to inspection the contacts at the
edestals, especially if your pedestal  is a distance from the main power
ource.

oe Guarino

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This whole "electric plug" thread has got me thinking that it would
be good to switch to SmartPlug connectors.  My boat has 50 Amp 110
volt shorepower, but that is a legacy of when it used to have
electrical cooking.  I never need or use more than 20 amps when
plugged in.  I use a heavy 50 amp cord at my home dock, but travel
with a 30 amp cord (plus a boatside 30->50 adapter).  The AC panel is
protected fifty amp breakers.

So, finally on to the question! Is there any downside to replacing
the boat-side socket with a 30 amp Smartplug.  I assume that the 30
amp breaker in the shore power pedestal will protect the cord and
that I don't have worry about the mis-match between the panel breaker
and the cord.  Am I right?

Thanks,

Steve