[C320-list] Electrical Question

[Jeff Hare]

John,

Just curious, if you have a laptop power brick plugged in or some other capacitive loads, would this trip a GFCI when turning on the power?

-jeff

John Frost <john at frostnet.net> wrote:

A GFCI works by comparing the current going out on the hot lead to the
current returning on the neutral.
If they are not equal, it assumes that some of the current is going to
ground, possibly thru a human, and trips the breaker.
http://en.wikipedia.org/wiki/Residual-current_device

Because all circuits have some amount of leakage to ground, it allows up to
5 milliamps to exist before it trips.
Your tripping when you hit the reverse polarity switch is not surprising as
that puts a small current to ground.

The tripping when you turn on your main circuit breaker is not good however.
That means you have some leakage to ground between your main circuit breaker
and the loads that it feeds.
I would disconnect all loads that the circuit breaker feeds, turn on shore
power, turn on your main circuit breaker and reattach the loads one by one.
When you get to the problem circuit, the GFCI will trip.
Then examine that circuit carefully.

Good luck, and be careful. 

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 Kurt R.
Budelmann, M.D.
Sent: Sunday, July 24, 2011 8:00 AM
To: C320-List at Catalina320.com
Subject: [C320-list] Electrical Question

My marina has GFI circuit breakers for my shore connection. When I plug
into shore power and flip on the main transom 30 amp breaker all is well.
But, when I either flip the test polarity switch to make sure it is working
or I flip the AC panel breaker with every other breaker off, the GFI shore
breaker trips. Neither of my two breakers trip.

I plugged into a non-GFI shore outlet (I swapped it in the breaker box on
shore) and everything works well.

I believe the issue is a ground problem on the boat as the current I draw
when running everything except the water heater is less than 1 amp when
plugged into a non-GFI shore breaker.

Has anyone else experienced this problem and any suggestions on how to fix
this?

I hired the marine electrician from the largest nearby marina and he claimed
that it is a problem with boats and GFI breakers. His facility does not use
any GFI breakers and they have hundreds of boats, some even over 100 feet.


__
Kurt Budelmann
Everwind, Catalina 320 #1035