Laptop trips GFI

No, NOTHING was plugged into the computer. Certainly no NMEA devices. That
said, I probably lied; I use a wireless mouse that MAY have been plugged in
to a USB port every time.

The laptop is a SONY VGN-A190 with Sony AC brick with a 3 wire plug. In a
year of use, I cannot remember it ever starting up without tripping the
GFI - EXCEPT TODAY!

This is totally unreal. I came up to the boat this afternoon and made sure
everything was turned off and nothing else plugged into the AC - only the
ships battery charger was on, even the DC was off. I fired up the AC
outlets and tuned on the computer, No fault. I turned off the computer,
turned everything on and tried again. Still no fault I tried 4 times and
can't cause it to fault. I'll try again in the morning after it has been
off over night.



"Larry" wrote in message

> w_tom wrote in :
>
>> First, to have a common mode noise (leakage), the computer
>> must have separate incoming and outgoing electrical paths.
>> Incoming is AC electric. What is the outgoing path?
>
> The ground in the computer is hooked to the ground in the NMEA bus, the
> printer through the printer cable, the computer's own troublesome charger.
> Because of any NMEA connections, it's also connected to that AC battery
> charger under the quarterberth, which is also hooked to AC ground.
>
> How many paths does it need??
>
>>
>> Second, leakage through a resistance is rare. Leakage
>> occurs more often through reactive devices. That means the
>> ohm meter will not measure leakage through components whose
>> conductivity increases with frequency and voltage. IOW these
>> leaks would appear as high resistance (notice I did not say
>> impedance) to the meter.
>
> This troublesome computer has a 3-prong grounded power plug, so we may
> assume it also has in input double pi line filter, or at least some disc
> ceramics in the .01 to .05 uF range between "hot" and neutral and ground.
> The ac current differential caused by the input filter's capacitors is
> more
> than enough to cause trips, which is why I wanted him to first plug the
> computer into a ground buster to eliminate the connection between the
> computer power supply ground and the boat AC ground to isolate this type
> of
> tripping. If the ground buster fixes the problem, he merely leaves it
> plugged into the ground buster and goes about his business, occasionally
> getting a tingle from the ground on the RS-232C shell, maybe. He'd be
> fine.
>
> Then, I was going to have him measure the voltage between the unconnected
> ground pin and boat ground to see how hot it was. You can imagine the $24
> switching power supply of the bargain laptop has nothing but the finest,
> mil-spec line filter parts....totaling, probably, 10 cents, tops....
>
>>
>> Third, all appliances have leakage. GFCI trip is not just
>> from one device. Sometimes it is leakage from numerous devices
>> combined. And yet the meter would test every device and see
>> no leakage from any of them.
>
> Maybe nothing else is plugged into this OUTLET GFI. It could serve more
> than one outlet from its internal terminals, though. The GFI outlet in my
> bathroom services the AC outlet on the side of my house, too.
>
>> Notice - without numbers then one can only speculate.
>
> Everything we do on this newsgroup is speculation...an exchange of guesses
> and ideas that usually come up with a solution or prod the asking party
> into taking a different path to the solution than the one he was
> taking....
>
 >> Stay informed about: Laptop trips GFI 

Another lie, the power brick is only two wire and the prongs aren't
polarized. Funny how different things look when you look at them. Maybe it
was the Dell that had the three wire plug.

"Larry" wrote in message

> w_tom wrote in :
>
>> First, to have a common mode noise (leakage), the computer
>> must have separate incoming and outgoing electrical paths.
>> Incoming is AC electric. What is the outgoing path?
>
> The ground in the computer is hooked to the ground in the NMEA bus, the
> printer through the printer cable, the computer's own troublesome charger.
> Because of any NMEA connections, it's also connected to that AC battery
> charger under the quarterberth, which is also hooked to AC ground.
>
> How many paths does it need??
>
>>
>> Second, leakage through a resistance is rare. Leakage
>> occurs more often through reactive devices. That means the
>> ohm meter will not measure leakage through components whose
>> conductivity increases with frequency and voltage. IOW these
>> leaks would appear as high resistance (notice I did not say
>> impedance) to the meter.
>
> This troublesome computer has a 3-prong grounded power plug, so we may
> assume it also has in input double pi line filter, or at least some disc
> ceramics in the .01 to .05 uF range between "hot" and neutral and ground.
> The ac current differential caused by the input filter's capacitors is
> more
> than enough to cause trips, which is why I wanted him to first plug the
> computer into a ground buster to eliminate the connection between the
> computer power supply ground and the boat AC ground to isolate this type
> of
> tripping. If the ground buster fixes the problem, he merely leaves it
> plugged into the ground buster and goes about his business, occasionally
> getting a tingle from the ground on the RS-232C shell, maybe. He'd be
> fine.
>
> Then, I was going to have him measure the voltage between the unconnected
> ground pin and boat ground to see how hot it was. You can imagine the $24
> switching power supply of the bargain laptop has nothing but the finest,
> mil-spec line filter parts....totaling, probably, 10 cents, tops....
>
>>
>> Third, all appliances have leakage. GFCI trip is not just
>> from one device. Sometimes it is leakage from numerous devices
>> combined. And yet the meter would test every device and see
>> no leakage from any of them.
>
> Maybe nothing else is plugged into this OUTLET GFI. It could serve more
> than one outlet from its internal terminals, though. The GFI outlet in my
> bathroom services the AC outlet on the side of my house, too.
>
>> Notice - without numbers then one can only speculate.
>
> Everything we do on this newsgroup is speculation...an exchange of guesses
> and ideas that usually come up with a solution or prod the asking party
> into taking a different path to the solution than the one he was
> taking....
>
 >> Stay informed about: Laptop trips GFI 

Not unreal. For example, some leakage could be between
wires inside an electric box that become more conductive when
humidity increases. Not conductive enough alone to trip a
GFCI, but conductive enough when combined with leakage from
the laptop.

Also the battery charger was on - but was it charging when
tests were conducted.

All appliances have galvanic isolation. That means (in
theory) low voltage circuits are isolated from AC mains - not
leakage. In reality, even galvanic isolation has microamp
leakage. I have even seen where a low voltage light causes
just enough leakage to create rare and intermittent GFCI trips
only when other appliances were powered just because a
chipmunk chewed into insulation of that low voltage (and
buried) wire.

You have a battery charger on the circuit. How much is it
leaking? The numbers, such as the normal leakage into safety
ground wire where that safety ground wire connects to breaker
box, are so important to those who would answer your posts.

Again, what was humidity then verses today? How long since
the last rain or a last boat hose down? And even what was
powered from the battery when you were testing previously?
Search for alternative circuits for current leakage - and that
even includes the battery charger. GFCI says you have leakage
somewhere. Now all we need do is find that leakage. Its easy
to say - and so damn difficult to put into reality.

Nothing unreal about your problem. Have solved these things
so many times that I have no belief in ghosts. But then
others long since give up before I do. My sympathies for your
frustration and my envy for your challenge.

JohnHH wrote:
> No, NOTHING was plugged into the computer. Certainly no NMEA
> devices. That said, I probably lied; I use a wireless mouse
> that MAY have been plugged in to a USB port every time.
>
> The laptop is a SONY VGN-A190 with Sony AC brick with a 3 wire
> plug. In a year of use, I cannot remember it ever starting up
> without tripping the GFI - EXCEPT TODAY!
>
> This is totally unreal. I came up to the boat this afternoon
> and made sure everything was turned off and nothing else
> plugged into the AC - only the ships battery charger was on,
> even the DC was off. I fired up the AC outlets and tuned on
> the computer, No fault. I turned off the computer, turned
> everything on and tried again. Still no fault I tried 4
> times and can't cause it to fault. I'll try again in the
> morning after it has been off over night.
 >> Stay informed about: Laptop trips GFI 

Thanks for your feed back. I have been getting it to fail again by
unplugging the adapter from the wall, waiting a minute and plugging it back
in. It seems like it happens far more consistantly if any other 110
appliance is running - like the refrigerator or heater or network router,
but not 100% consistant. It's raining cats and dogs today so I am sure I
have experienced it in every weather condition.

By the way, my digital multimeter measures about 40 meg ohms before it goes
to infinity.

I am one of those who is going to give it up. I don't think it is serious
and I'm losing interest. The problem will go away anyway when I replace
the AC-DC converter with a DC-DC one. I'm not really frustrated, I was just
curious. I fully expected someone to say, oh yea, that always happens with
those power bricks.

I'm going to bag this thing for now.

Thanks to all of you who replied, it's been informative.

John




"w_tom" wrote in message
...
> Not unreal. For example, some leakage could be between
> wires inside an electric box that become more conductive when
> humidity increases. Not conductive enough alone to trip a
> GFCI, but conductive enough when combined with leakage from
> the laptop.
>
> Also the battery charger was on - but was it charging when
> tests were conducted.
>
> All appliances have galvanic isolation. That means (in
> theory) low voltage circuits are isolated from AC mains - not
> leakage. In reality, even galvanic isolation has microamp
> leakage. I have even seen where a low voltage light causes
> just enough leakage to create rare and intermittent GFCI trips
> only when other appliances were powered just because a
> chipmunk chewed into insulation of that low voltage (and
> buried) wire.
>
> You have a battery charger on the circuit. How much is it
> leaking? The numbers, such as the normal leakage into safety
> ground wire where that safety ground wire connects to breaker
> box, are so important to those who would answer your posts.
>
> Again, what was humidity then verses today? How long since
> the last rain or a last boat hose down? And even what was
> powered from the battery when you were testing previously?
> Search for alternative circuits for current leakage - and that
> even includes the battery charger. GFCI says you have leakage
> somewhere. Now all we need do is find that leakage. Its easy
> to say - and so damn difficult to put into reality.
>
> Nothing unreal about your problem. Have solved these things
> so many times that I have no belief in ghosts. But then
> others long since give up before I do. My sympathies for your
> frustration and my envy for your challenge.
>
> JohnHH wrote:
>> No, NOTHING was plugged into the computer. Certainly no NMEA
>> devices. That said, I probably lied; I use a wireless mouse
>> that MAY have been plugged in to a USB port every time.
>>
>> The laptop is a SONY VGN-A190 with Sony AC brick with a 3 wire
>> plug. In a year of use, I cannot remember it ever starting up
>> without tripping the GFI - EXCEPT TODAY!
>>
>> This is totally unreal. I came up to the boat this afternoon
>> and made sure everything was turned off and nothing else
>> plugged into the AC - only the ships battery charger was on,
>> even the DC was off. I fired up the AC outlets and tuned on
>> the computer, No fault. I turned off the computer, turned
>> everything on and tried again. Still no fault I tried 4
>> times and can't cause it to fault. I'll try again in the
>> morning after it has been off over night.
 >> Stay informed about: Laptop trips GFI 

"JohnHH" wrote in


> This is totally unreal. I came up to the boat this afternoon and made
> sure everything was turned off and nothing else plugged into the AC -
> only the ships battery charger was on, even the DC was off. I fired
> up the AC outlets and tuned on the computer, No fault. I turned off
> the computer, turned everything on and tried again. Still no fault I
> tried 4 times and can't cause it to fault. I'll try again in the
> morning after it has been off over night.
>

See there? I knew we could fix it on the newsgroup!...(c;

Ok, next problem to solve.......

--
Larry
 >> Stay informed about: Laptop trips GFI 

w_tom wrote:
> First, to have a common mode noise (leakage), the computer
> must have separate incoming and outgoing electrical paths.
> Incoming is AC electric. What is the outgoing path?
>

Well, that's why I lack enthusiasm for the common mode noise
explanation. But it can and does happen, of course. The question is, as
you suggested, what are the numbers. Simply imagine some capacitance to
ground on the AC lines. This forms the return circuit for the
high-frequency noise that trips the GFCI. The SMPS power bricks are
supposed to contain filtering to prevent this kind of "interference" but
the filter caps might have dried out.


> Second, leakage through a resistance is rare. Leakage
> occurs more often through reactive devices. That means the
> ohm meter will not measure leakage through components whose
> conductivity increases with frequency and voltage. IOW these
> leaks would appear as high resistance (notice I did not say
> impedance) to the meter.
>

I think the leakage resistance is easier to understand if you consider
that all real-world capacitors and inductors contain some resistance.
You can imagine a real capacitor as a perfect capacitor (no resistance
or inductance) in parallel with a perfect resistor. That resistance is
called series resistance or leakage resistance. Sometimes it is
frequency-sensitive, but that is not what I believe we are seeing here.

The ohmmeter will readily measure this resistance (if it is not too
high) because it is quite real.

> Third, all appliances have leakage. GFCI trip is not just
> from one device. Sometimes it is leakage from numerous devices
> combined. And yet the meter would test every device and see
> no leakage from any of them.

Yes, I agree fully. However, it was established in an earlier post that
nothing but the computer was connected to this GFCI receptacle. And that
nothing was connected to the computer.

>
> To put numbers to what was posted - appliances typically
> leak less than 150 microamps when working normally. Show me
> the meter that will measure this 800 Kilohm or 1 Megohm
> resistor? Meter will declare infinite resistance (more than
> tens of megohms) when leakage says 'impedance' (not
> resistance) is lower.

Not sure what you are saying here. Almost any meter will measure 1
megohm of resistance. I don't believe the leakage causing the problem is
due to a low-reactance condition between the hot wire and the grounding
conductor. I believe the problem may be due to a (relatively) low
resistance between the hot wire and the grounding conductor. I believe
that resistance may be leakage resistance in a capacitor in the power
brick. It is a lot more common, I think, for appliances to develop "low"
resistance leakages to ground and relatively uncommon for them to
develop "low" reactances to ground.

>
> Not mentioned is the brand name and model of that laptop.
> Not mentioned is whether that power brick is from the
> manufacturer or from a third party. Not mentioned is whether
> a useless power strip protector is being used. I am not sure
> whether the power brick is two prong or three - another
> critical fact.
>
It appears a 3-prong plug is being used.

> But this is certain. Whether the laptop starts up or is
> powered constantly, the current coming in one wire will always
> equal the current going out the other - if hardware is working
> properly. For those two currents to be different, then
> current must have another (third) path out of the laptop /
> power brick system. So where is that third path? And how
> much current in that third path.
>
Yes. And the only path I can imagine is as described earlier.

> Notice - without numbers then one can only speculate. Get
> numbers. How much current is in the safety ground wire for
> the entire GFCI circuit?

That shouldn't matter. The GFCI will work as well without a ground wire
as with one carrying 20 amps! It is not even connected to the ground
wire. As long as there is no net current in the hot and grounded
conductor pair, the GFCI shouldn't trip.

Does the laptop cause this problem
> when it is the only item on that GFCI circuit?

Yes.

Contrary to
> what that meter will say - all appliances have some leakage -
> which is why the ohm meter cannot report 'real' amount of
> leakage.
>

If we measure a leakage on the power brick of 20,000 ohms, then
regardless of what is happening with other appliances, we have
established that the power brick is capable of tripping the GFCI all by
itself and we need look no further. An alternative to using the ohmmeter
is to use a sensitive clamp-meter (or even an AC ammeter) on the
grounding conductor. Keeping in mind, of course, that these instruments
are not likely to give a meaningful measurement of the high-frequency,
common-mode noise that is the other candidate explanation for the
tripping. An oscilloscope or spectrum analyzer would be more useful.

Since there are no other appliances on that GFCI circuit, then other
appliances are irrelevant to this particular problem.

Hope I haven't added to the confusion.

Chuck
 >> Stay informed about: Laptop trips GFI 

JohnHH wrote:
> Another lie, the power brick is only two wire and the prongs aren't
> polarized. Funny how different things look when you look at them. Maybe it
> was the Dell that had the three wire plug.

So, progress, eh?

It's easier to see when you use your eyes. It's easier to think
when you don't put garbage into your brain.

So, with a 2 wire cableset, unpolarised, did you try it plugged in
both ways?

Does it do "it" both ways? Is there a great bloody gash and bare
wires hanging out the cableset? Covered with black tape? "Sealed up"
with smunge from years of handling? Smunge is that black goo that
costs so much when spread thinly, hundreds of coats, on "antique"
furniture. It comes from human hands and exhalations, sometimes
called "patina."

If only one way, there is probably a .01 uf "decoupling" capacitor
from charger "chassis" ground to one side of the supply, depending
on which way it's plugged in. It will be leaky, or possibly open.
Replace it with a good one. Don't ask how I know, I've been told I
get too technical. The device might have internal transformer caused
eddy currents or switching transients capable of tunnelling through
the insulation into the ether.

Otherwise, there ain't no way this thing can pop a gfci unless there
is leakage through the electrocutee. That's you. Try it again with
rubber boots on, and rubber gloves. If that solves the problem look
for something like an almost dried puddle of puke somewhere near
where your hand contacts the case or perhaps a salty damp berth
cushion and sweaty underpants, all too close to the wire mesh ssb
"ground" plane or something really strange.

Reroute the power cableset, away from where it usually is. Try
again. Does it happen at only one one outlet / location?

Laugh if you want, but this is the real world talking, and truth is
stranger than friction, as they try to say...

Does this thing have an antistatic plastic case, possibly conductive
enough to allow this leakage? Paint it with a good insulating
varnish, or keep it in a plastic baggie.

Buy a different brand of gfci, maybe a cheaper one will serve better.

Terry K


> "Larry" wrote in message
>
>
>>w_tom wrote in :
>>
>>
>>> First, to have a common mode noise (leakage), the computer
>>>must have separate incoming and outgoing electrical paths.
>>>Incoming is AC electric. What is the outgoing path?
>>
>>The ground in the computer is hooked to the ground in the NMEA bus, the
>>printer through the printer cable, the computer's own troublesome charger.
>>Because of any NMEA connections, it's also connected to that AC battery
>>charger under the quarterberth, which is also hooked to AC ground.
>>
>>How many paths does it need??
>>
>>
>>> Second, leakage through a resistance is rare. Leakage
>>>occurs more often through reactive devices. That means the
>>>ohm meter will not measure leakage through components whose
>>>conductivity increases with frequency and voltage. IOW these
>>>leaks would appear as high resistance (notice I did not say
>>>impedance) to the meter.
>>
>>This troublesome computer has a 3-prong grounded power plug, so we may
>>assume it also has in input double pi line filter, or at least some disc
>>ceramics in the .01 to .05 uF range between "hot" and neutral and ground.
>>The ac current differential caused by the input filter's capacitors is
>>more
>>than enough to cause trips, which is why I wanted him to first plug the
>>computer into a ground buster to eliminate the connection between the
>>computer power supply ground and the boat AC ground to isolate this type
>>of
>>tripping. If the ground buster fixes the problem, he merely leaves it
>>plugged into the ground buster and goes about his business, occasionally
>>getting a tingle from the ground on the RS-232C shell, maybe. He'd be
>>fine.
>>
>>Then, I was going to have him measure the voltage between the unconnected
>>ground pin and boat ground to see how hot it was. You can imagine the $24
>>switching power supply of the bargain laptop has nothing but the finest,
>>mil-spec line filter parts....totaling, probably, 10 cents, tops....
>>
>>
>>> Third, all appliances have leakage. GFCI trip is not just
>>>from one device. Sometimes it is leakage from numerous devices
>>>combined. And yet the meter would test every device and see
>>>no leakage from any of them.
>>
>>Maybe nothing else is plugged into this OUTLET GFI. It could serve more
>>than one outlet from its internal terminals, though. The GFI outlet in my
>>bathroom services the AC outlet on the side of my house, too.
>>
>>
>>> Notice - without numbers then one can only speculate.
>>
>>Everything we do on this newsgroup is speculation...an exchange of guesses
>>and ideas that usually come up with a solution or prod the asking party
>>into taking a different path to the solution than the one he was
>>taking....
>>
>
>
>
 >> Stay informed about: Laptop trips GFI 

Thanks Terry, you know the first thing I was going to do when I realized it
wasn't a grounded plug is try reversing it, but I never got around to it,
but I will the next time at the boat.

As I said, this is more a nuisance than a problem. I don't consider it a
safety issue and thus I'm not planning on putting a lot of effort into
solving it--bigger issues to focus on.

John

"Terry Spragg" wrote in message

> JohnHH wrote:
>> Another lie, the power brick is only two wire and the prongs aren't
>> polarized. Funny how different things look when you look at them. Maybe
>> it was the Dell that had the three wire plug.
>
> So, progress, eh?
>
> It's easier to see when you use your eyes. It's easier to think when you
> don't put garbage into your brain.
>
> So, with a 2 wire cableset, unpolarised, did you try it plugged in both
> ways?
>
> Does it do "it" both ways? Is there a great bloody gash and bare wires
> hanging out the cableset? Covered with black tape? "Sealed up" with smunge
> from years of handling? Smunge is that black goo that costs so much when
> spread thinly, hundreds of coats, on "antique" furniture. It comes from
> human hands and exhalations, sometimes called "patina."
>
> If only one way, there is probably a .01 uf "decoupling" capacitor from
> charger "chassis" ground to one side of the supply, depending on which way
> it's plugged in. It will be leaky, or possibly open. Replace it with a
> good one. Don't ask how I know, I've been told I get too technical. The
> device might have internal transformer caused eddy currents or switching
> transients capable of tunnelling through the insulation into the ether.
>
> Otherwise, there ain't no way this thing can pop a gfci unless there is
> leakage through the electrocutee. That's you. Try it again with rubber
> boots on, and rubber gloves. If that solves the problem look for
> something like an almost dried puddle of puke somewhere near where your
> hand contacts the case or perhaps a salty damp berth cushion and sweaty
> underpants, all too close to the wire mesh ssb "ground" plane or something
> really strange.
>
> Reroute the power cableset, away from where it usually is. Try again. Does
> it happen at only one one outlet / location?
>
> Laugh if you want, but this is the real world talking, and truth is
> stranger than friction, as they try to say...
>
> Does this thing have an antistatic plastic case, possibly conductive
> enough to allow this leakage? Paint it with a good insulating varnish, or
> keep it in a plastic baggie.
>
> Buy a different brand of gfci, maybe a cheaper one will serve better.
>
> Terry K
>
>
>> "Larry" wrote in message
>>
>>
>>>w_tom wrote in :
>>>
>>>
>>>> First, to have a common mode noise (leakage), the computer
>>>>must have separate incoming and outgoing electrical paths.
>>>>Incoming is AC electric. What is the outgoing path?
>>>
>>>The ground in the computer is hooked to the ground in the NMEA bus, the
>>>printer through the printer cable, the computer's own troublesome
>>>charger.
>>>Because of any NMEA connections, it's also connected to that AC battery
>>>charger under the quarterberth, which is also hooked to AC ground.
>>>
>>>How many paths does it need??
>>>
>>>
>>>> Second, leakage through a resistance is rare. Leakage
>>>>occurs more often through reactive devices. That means the
>>>>ohm meter will not measure leakage through components whose
>>>>conductivity increases with frequency and voltage. IOW these
>>>>leaks would appear as high resistance (notice I did not say
>>>>impedance) to the meter.
>>>
>>>This troublesome computer has a 3-prong grounded power plug, so we may
>>>assume it also has in input double pi line filter, or at least some disc
>>>ceramics in the .01 to .05 uF range between "hot" and neutral and ground.
>>>The ac current differential caused by the input filter's capacitors is
>>>more
>>>than enough to cause trips, which is why I wanted him to first plug the
>>>computer into a ground buster to eliminate the connection between the
>>>computer power supply ground and the boat AC ground to isolate this type
>>>of
>>>tripping. If the ground buster fixes the problem, he merely leaves it
>>>plugged into the ground buster and goes about his business, occasionally
>>>getting a tingle from the ground on the RS-232C shell, maybe. He'd be
>>>fine.
>>>
>>>Then, I was going to have him measure the voltage between the unconnected
>>>ground pin and boat ground to see how hot it was. You can imagine the
>>>$24
>>>switching power supply of the bargain laptop has nothing but the finest,
>>>mil-spec line filter parts....totaling, probably, 10 cents, tops....
>>>
>>>
>>>> Third, all appliances have leakage. GFCI trip is not just
>>>>from one device. Sometimes it is leakage from numerous devices
>>>>combined. And yet the meter would test every device and see
>>>>no leakage from any of them.
>>>
>>>Maybe nothing else is plugged into this OUTLET GFI. It could serve more
>>>than one outlet from its internal terminals, though. The GFI outlet in
>>>my
>>>bathroom services the AC outlet on the side of my house, too.
>>>
>>>
>>>> Notice - without numbers then one can only speculate.
>>>
>>>Everything we do on this newsgroup is speculation...an exchange of
>>>guesses
>>>and ideas that usually come up with a solution or prod the asking party
>>>into taking a different path to the solution than the one he was
>>>taking....
>>>
>>
>>
>>
>
 >> Stay informed about: Laptop trips GFI