johnhh wrote:

All of my 110 outlets on the boat are protected through GFI. Whenever I plug
my laptop charger in or turn on the computer with it plugged in, it trips
the GFI. If I reset it a time or two or three, it will hold and work fine
until the next time. Interestingly, it will even trip the GFI on a parallel
circuit. I am guessing that it has something to do with the large capacitor
in the charging unit charging up. Does anyone have an explanation and/or
solution?

thanks
john



All gfi protected circuit branches the same? If so, a laptop fault,
potentially dangerous should be investigated by a professional. Is
your laptop connected to external speakers, or other accessories,
possibly interconnected with equipment on a different phase of mains
power?

Most laptops use only 2 wire plugs, so cannot have a current
imbalance in the cableset typically the cause of gfi tripping. You
may have a bad gfi. You may have a salty moist sweat stain on plug
terminal, wire, grip, etc, to some earthed part of the boat. Clean
the plug end with a mild detergent and dry thoroughly.

If yours has a 3 wire plug, it may have a marginal leakage path from
a hot terminal to the safety ground. This can be difficult to
prove, as the current is so small, and it trips so fast.

You could test with a 2 wire extension cord, to see if this stops
the tripping. It might not be safe to use it regularly without
repairing the cause. You might be best to use insulating gloves
while doing this test.

It seems unlikely there is an electrical contact on the case of the
laptop that might be in contact with an earth or even your hand, but
that too would only indicate an internal leakage through the power
supply or charger, which could be lethal, if circumstances get right.

As to why it might cause tripping a gfi in some other part of the
power system, you got me there, buddy, unless one gfi is feeding the
other, and they are just taking turns at tripping;-)

I think startup current surges would not affect a gfic, first
because as far as I know, they are not designed to be overcurrent
circuit breakers, except insofar as safety imbalance current is
concerned and second, no laptop should draw so large a surge. If so,
I would suspect a resistive or reactive neutral or hot connection
path. Do you have galvanic diode blockers in your shoreside earth
line connector path? Do you have a wireless card in your laptop?

Are you, as did a friend of mine, amazingly still alive, using a 110
v device in series with a 220 v flourescent ballast circuit?
Stranger things exist in truth than in fiction.

Very curious.

Terry K