[C38] melting shore power connector

Mon Jun 6 19:54:21 EDT 2011

Don,
The fellow from Matheson Electronics just called me about my depth finder 
which wasn't working. How fun is that? He found a broken wire in the 
pedestal and fixed it.  I asked him about "arcing" and he said that the 
switch in the upper left hand corner (breaker) should be in "off" position 
when sailing. This cuts off connection to shore power. He recommends having 
it in the "off" position as well as having the shore power at the dock in 
"off" position when connecting or disconnecting cable.  When both ends are 
connected....turn on the dock as well as the vessel. This prevents arcing as 
well as preventing carrying a "live" wire from boat to dock. I usually leave 
from cable on vessel so I don't worry about carrying live wire.
Patrick
----- Original Message ----- 
From: "Chuck Finn" <charles at finn.ws>
To: "Catalina 38 Listserve" <listserve at catalina38.org>
Sent: Monday, June 06, 2011 2:40 PM
Subject: Re: [C38] melting shore power connector


> Don,
> Your earlier comments on this got me to looking at mine, which was painful 
> to almost impossible!  What a situation where electrical power is running 
> around without any protection on the boat....   I guess I am lucky to be a 
> freshwater boat because there was no deterioration (detectable).   I will 
> note that ALL of the original wiring is just copper strand!  If my boat 
> was in saltwater...  I would be seriously considering a re-wire....
> Guess the good news is that a lot of my wiring has already been replaced 
> with upgrades over the years.  I just replaced most of my electrical panel 
> (circuit breakers) and removed probably 100 feet of old wire that was just 
> lying around.  Some of it live, but just cut and taped off.  And there was 
> at least another 100 feet of old stereo wire!
>
> Chuck Finn
> Mighty Quinn #114
> Great Lakes
>
> On 6/6/2011 5:20 PM, Don Strong wrote:
>> The dockmaster at Emery Cove Yacht Harbor, Diane, where Patrick and I are 
>> berthed, told me that arcing and corroded shore power service is the only 
>> cause of boat fires in her long experience at this large marina. Mr. 
>> Matheson at the marine electronics business by Diane's office also 
>> emphasized to me the risk of these old 120 V systems. He has a rouge's 
>> gallery of melted shore power installs in his office. As I posted 
>> earlier, it isn't only the plug that can melt and cause fires. Old, 
>> corroded 120V wiring inside the boat can also arc, heat up, and cause 
>> fires. A third marine engineer recommended that I make sure that the 
>> wiring inside the boat was up to the task of 120V alternating current. 
>> His words, "...important to remember that the circuit breaker might not 
>> protect the boat wiring from arcing, overheating, and fire." He convinced 
>> me to look for corroded shore power wire inside the boat. I found it. 25 
>> year old green and blackened 120V wiring inside the boat.
>> Don
>>
>> On 6/6/11 1:56 PM, Chuck Finn wrote:
>>> Patrick,
>>> That would be wishful thinking!  You still only work off the one 15 amp 
>>> breaker.   This makes your problem look even more like arcing as you 
>>> clearly are not overloading the 30 amp circuit if you are not using the 
>>> water heater!  Remember the power cable is rated for at least 30 amps 
>>> and you clearly are not coming close to that number.
>>>
>>> All the best,
>>> Chuck Finn
>>> Mighty Quinn #114
>>> Great Lakes
>>>
>>> On 6/6/2011 4:46 PM, Patrick Harpole wrote:
>>>> Chuck,
>>>> I "never" use my water heater.....get hot water only when engine is 
>>>> running. Does that mean I have 3000 watts?
>>>> I assume I don't.
>>>> Patrick
>>>> ----- Original Message ----- From: "Chuck Finn" <charles at finn.ws>
>>>> To: "Catalina 38 Listserve" <listserve at catalina38.org>
>>>> Sent: Monday, June 06, 2011 11:59 AM
>>>> Subject: Re: [C38] shore power
>>>>
>>>>
>>>>> 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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>>>>>
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