[C320-list] AC reversed polarity light

[John Frost]

That depends on the indicator light. 
If it is a tiny "grain of wheat" bulb or an LED requiring only milliamps to
light, almost any parasitic load could be enough.

Happy Sailing!

John
2007 C320MKII
Hull 1118
Guntersville, AL




-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Scott Thompson
Sent: Wednesday, July 07, 2010 12:39 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] AC reversed polarity light

John:  Thanks a lot for this.  It's very helpful.  Your third 
possibility seems most likely.  However I was getting the reversed 
polarity light indicator before turning on any loads.  I may have turned 
on the AC breaker itself, however, which would add a very tiny load from 
the LED on the panel.  Could that be enough?

Scott

John Frost wrote:
>>From your description of the circuit, either of 3 problems could cause the
> light to illuminate:
> 
> 1. A reversed hot and neutral. That could be at the dock (you have ruled
> that out), in the cable (Very unlikely unless you have recently changed
> connectors) or on the boat (Very unlikely since it used to work fine).
> 
> 2.A reversed hot and ground at the same locations (very dangerous but very
> unlikely since nothing has changed and you are not getting shocked) 
> 
> 2. A bad connection in the neutral circuit, most likely on the boat or
power
> cable connectors (very likely). A corroded connection in this "return leg"
> causes the neutral on the boat to be energized (as compared to the ground)
> by the current that has gone thru your AC loads because it can't all get
> back to the dock outlet. I would start with a careful inspection of the
> power cord connectors at both ends and the outlets that they plug into.
They
> go bad frequently. Look for heat discoloration or corrosion. You might
also
> try a neighbor's cord. If a visual inspection doesn't turn it up, you will
> need to test the voltage between safety ground and the neutral on both
sides
> of each connection with an AC volt meter, with all of the AC boat loads on
> (maybe plug in a heater to give a high load). Note that while the bad
> contact is probably in your part of the circuit, it could also be in the
> dock wiring. Be careful, 120 volts can easily kill. 
> 
> Happy Sailing!
> 
> John
> 2007 C320MKII
> Hull 1118
> Guntersville, AL
> 
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> 
> 
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Scott
Thompson
> Sent: Wednesday, July 07, 2010 8:37 AM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] AC reversed polarity light
> 
> Thanks Irv.  I suppose I should keep one of those on board.
> 
> I know that the problem is not on the dock.  I have this problem at all 
> dockside outlets now, including ones that work fine for other people and 
> worked fine for me not long ago.  It's clearly something between the 
> dockside outlet and the AC panel on the boat.  I'm looking for some way 
> to track the specific faulty part or connection.
> 
> To you electrical experts out there:  Looking at the AC wiring diagram, 
> the reverse polarity light appears to be wired to detect a voltage 
> present between the neutral (white wire) input side of the main AC 
> breaker on the panel and the AC ground bus bar behind the panel.  What 
> failure of my wiring would cause a voltage to appear there consistently? 
>   It isn't clear to me why an open circuit on either neutral or ground 
> would cause either one to show up as "hot", which is what you would 
> expect with an actual polarity reversal.
> 
> I have no inverter, and the factory stock AC installation.
> 
> Scott Thompson
> Surprise, #653
> 
> Irving Grunes wrote:
>> All,
>> See :
>> http://www.tequipment.net/IdealReceptacleTesters.asp
>> for and electrical tester to check the outlets on the boat.
>> If the oytlets are bad, then the dock receptacle is probably bad.
>> Irv Grunes
>> #851
>>
>> On Wed, Jul 7, 2010 at 8:13 AM, Scott Thompson
> <surprise at thompson87.com>wrote:
>>> Thanks.  That's where my suspicions lie.  Is there some way to test? And
>>> does anyone know a part number or source?
>>>
>>> Scott
>>> Surprise, #653
>>>
>>> vpweikel at comcast.net wrote:
>>>
>>>> Scott,
>>>>
>>>>
>>>> Had the same reverse polarity issue a few years back.
>>>>
>>>>
>>>> Turned out to be the shore plug on the stern.
>>>>
>>>>
>>>>
>>>>
>>>> Paul Weikel
>>>> Second Chance
>>>> #361
>>>>
>>>> ----- Original Message ----- From: "Jim Sweet"
> <jamesweet at frontiernet.net>
>>>> To: C320-List at Catalina320.com Sent: Tuesday, July 6, 2010 8:17:15 AM
>>>> Subject: Re: [C320-list] AC reversed polarity light
>>>> Had the same issue on our old Pearson 332.  Also had an intermittent
>>>> flicker in the reversed polarity light.  Turned out to be a bad power
> cord.
>>>> Jim Sweet TGIF (Thank God It Floats) 901
>>>> ----- Original Message ----- From: "Scott Thompson" <
>>>> surprise at thompson87.com> To: "Catalina320.org"
> <C320-List at Catalina320.org>
>>>> Sent: Monday, July 05, 2010 9:38 PM Subject: [C320-list] AC reversed
>>>> polarity light
>>>>
>>>>  On our recent cruise we found that the reverse polarity light came on
>>>>> when we tested the AC hookup in 2 different marinas, and then again
> back on
>>>>> our home pier.  Since there was no indication of improper wiring at
any
> of
>>>>> these locations, and since we had no trouble at the home pier at the
> start
>>>>> of the trip, I assume that the problem is somewhere in my boat or
power
>>>>> cord.  The power cord passes a simple end to end continuity check on
> each of
>>>>> the three conductors, and there is no sign of any shorts.  Does anyone
> have
>>>>> suggestions on what to look for next?  It's occurred to me that
perhaps
> I
>>>>> need to replace the shore power connector on the transom.  It looks
OK,
> but
>>>>> after 11 years, maybe the weather has taken its toll.
>>>>> My recollection is that faults other than reverse polarity can cause
>>>>> these kinds of symptoms but I do not remember the details.
>>>>> --
>>>>> Scott Thompson Surprise, #653
>>>>>
>>>>
>>> --
>>> Scott Thompson
>>> Surprise, #653
>>>
> 

-- 
Scott Thompson
Surprise, #653