[C320-list] 120 volt power circuit issue

[Chris Burti]

I had a problem with one repeatedly tripping (the one by the chart table),
so i replaced it with a 20 amp industrial duty outlet and have had  only
one trip in the three years since. We do have a an isolator.

Chris Burti
Commitment #867
Farmville, NC



On Wed, Jul 31, 2019 at 1:33 PM Dave Hupe <hoopdtwo at yahoo.com> wrote:

> I have 2 ground fault circuit interrupter (GFCI) outlets on the 120 volt
> AC power side that control all of the AC outlets on my 1994 boat.  I've had
> them trip a couple times lately, but only when I come back in and reconnect
> shore power.  I hadn't been turning off the master breaker switch at the
> stern (as I really should) before I connect or disconnect the shore power
> cord.  When I did turn the switch off before disconnecting/reconnecting,
> the GFCIs don't trip.
>
> I thought that maybe the GFCIs were "tired" (probably original equipment)
> and/or I'm getting a small "zap" when I make the shore power connection
> that is making them trip. I figured it might be a good idea to install new
> GFCIs (assuming old and possibly the problem).  So, I bought new 15 amp
> ones.  I installed one, turned the power back on, and it tripped
> immediately each time I applied power.  I reinstalled the old one and it
> did not trip.  I returned the 15 amp units to the store and got 20 amp
> GFCIs (I finally saw on the old ones that they were 20 amp).  However the
> same thing happened .... It tripped, but the old one doesn't when
> reinstalled.
>
> The new GFCIs reportedly do automatic  "self tests" every 3 seconds per
> the packaging.  Other slightly cheaper ones reportedly do tests every 1.5
> minutes. So, I don't know if these new GFCIs are more sensitive than the
> old ones (which likely don't self test), or is the self test feature itself
> a problem?
>
> A friend with a newer 320 (year 2000) mentioned about having an isolation
> transformer on his boat and wondering if that would interfere with the new
> type GFCIs.  I think we've resolved that he actually has a galvanic
> isolator that Catalina started installing in 1998
> https://www.catalinadirect.com/shop-by-boat/catalina-380390/electrical/galvanic-isolator-30-amp/
> I'm not sure if an isolation transformer is really different than a
> galvanic isolator.  However, my boat has neither being older.
>
> I'd like to resolve this to feel safer, but don't know what to do.  I
> wonder if I have a poor ground connection related to the AC outlets?
>
> Any ideas/similar experience?
> Dave Hupe
> 1994 Cat 320 (#32) "Mayan Sun"
> Holland, MI
>