GFCI's

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A partial short between the ground and the neutral in the extension cord or elsewhere could cause the OPs symptoms.
Mark
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On 12/4/2015 7:11 AM, snipped-for-privacy@yahoo.com wrote:

What causes it to *heal*? And also reappear?
"Cold flow" from a neutral conductor to case can likewise cause load-related GFCI trips. But it doesn't "recover" and also "recur" -- not in a matter of tens of seconds.
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On Friday, December 4, 2015 at 10:10:29 AM UTC-5, Don Y wrote:

If it is a partial short from neutral to ground, the GFI will trip only when there is a large current flow, for example during the turn on surge of cold bulbs.
If even a small percentage of the current flows through the ground, it will trip the GFI.
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On 12/3/2015 5:47 PM, snipped-for-privacy@aol.com wrote:

How do you define "paying"? If I spend an hour doing something that doesn't yield any results, I've lost an hour of my time. No amount of money can buy that hour back, again! (this was the rationale that I used to stop letting other people -- bosses, clients -- waste my time "for a paycheck")
I chuckle when I hear folks claim that their time is "worth" $X/hour. "Yeah, *if* someone is standing nearby with $X in their hands, willing to give it to you for the next hour of your life!" :>
Working for myself, it is very easy to put a number like that on my time; how many MORE hours do I want to bill, this month? I.e., there are folks who *will* trade their $X for that hour -- so, I know the hour is worth AT LEAST that much.
Whether it is worth <whatever> *more* I want to think it may be worth is always debatable. But, if you're not starving, you can elect to horde your hours and "spend" them on what YOU find enjoyable. I choose that approach at this point in my life (no one ever died wishing they'd worked a few more hours!)

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On 12/03/2015 1:21 PM, Don Y wrote: ...

One quick one is the possibility of the extension cord having a fault (particularly as noted, if it's one of the pretty-common type with the indicator light in the plug). It's a common element in all the combinations done to date and is simple as compared to many of the other things you've tried already or proposing to eliminate.
"Willy-nilly" is pretty much what you've done to date; the above is, as noted, one common element in all. It may _not_ have any bearing but then again, if it just turned out to be so, then all the other pontificating is of little value.
(PS) And, no, on the GFCI circuit breaker I'm not specifically aware -- don't have any and plan to live out my life that way. :) If it's not feasible, then ok, so be it.
--


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On 12/3/2015 12:44 PM, dpb wrote:

But, it has to be a "leak" -- as the problem doesn't manifest when plugged into a non-GFCI circuit.
And, that "leak" has to somehow be healing itself, then reappearing (based on whether or not the lights have been on or off and for how long!)

I've been "willy nilly" in an attempt to be polite to folks offering suggestions here. It's not how *I* would have tackled the problem. But, having asked, it would be rude to dismiss suggestions when (in MOST cases -- change breaker, change load, plug into different outlet, swap extension cord, etc.) I can just do the test to humor the respondent.
But, the "try this" can go on indefinitely. And, you can always rationalize a semi-legitimate justification for each such attempt! (e.g., ALL of the lamps have been out in the elements; perhaps they've *all* been affected in some way! So, it doesn't matter which strings you try, the problem will persist -- cuz it's in ALL of them!)
[I worked on a piece of test equipment many years ago. There was a short between two of the power supplies -- on a "circuit board" that was 2 ft wide, 6 feet long and contained *thousands* of components! I.e., the short could be in any of those components. Or, in the board, itself. Troubleshooting all those potential connections -- considering that the short was an UNINTENDED connection -- would be a daunting task. Better to replace the board and start over... after several months of delay!
I hypothesized that a capacitor could be the "short" -- they were all over the (brand new!) board. Of course, *which* capacitor was the problem!
So, I simply picked one AT RANDOM, removed it from the circuit and tested it.
Shorted!
My colleagues looked at me like I had just walked on water: not only had I come up with the "problem" but also managed to find the defective capacitor, on my first attempt!
Boss, quickly turned that optimism into an accusation: "There's no way you could have known that THAT capacitor was the failed device! You *put* that there!!"
<frown> Sort of unfair -- given that I'd just saved his *ss! I came back later to be greeted by news that *all* of the capacitors were shorted! (WTF??) Turned out, the board manufacturer had installed capacitors with the wrong voltage rating and, as soon as we had applied power, they all went "pffft!"
So, there was no "luck" involved in my finding THE shorted capacitor. OTOH, there was *genius* in my REASONING that it could be *a* shorted capacitor -- and not a wire that was misplaced (of the tens of thousands on the board)!]

My problem *has* to be related to the GFCI characteristics of the "circuit". And, not the GFCI detection itself (faulty breaker) but, rather, some aspect of what it is testing that the current configuration happens to "tickle" -- and, only in those cases where it *does* tickle (also accounting for those cases where it *doesn't*!)
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On 12/03/2015 3:20 PM, Don Y wrote: ...

Agreed, and all I'm suggesting doing is eliminating one possible source for that place...it could be there's a damaged area but not drastically such that it's visibly obvious that's let some moisture in and after a short time it "bakes" it out locally to the point the problem isn't apparent. But, as you've demonstrated, when it is off for any period of time, there's enough inside there to recreate the leakage path.
Now, granted, it's possible it's in one of these other locations but again, it seems silly and the _most_ time-consuming and least likely to reach nirvana quickest to start down all of the various other components looking for the case when there's still one common component that hasn't been yet eliminated. (Unless, of course, you just happen to be lucky and it's the first one you try, but that is again back to the luck of the draw, nothing you've done via "scientific method". At least I'm starting with a common cause location.
(Besides, just think how much fun you'll have when you can say "I told you so!!!!")
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On Thu, 03 Dec 2015 09:45:28 -0700, Don Y

Are they listed for the panel? If it is an "old ch" panel the GFCIs were not original install - correct? or is it not that "old" a CH panel?
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On 12/3/2015 2:47 PM, snipped-for-privacy@snyder.on.ca wrote:

CH GFCI's for this particular panel. Did my homework when I bought them. Hard to find cuz the panel is old -- can't just walk into a Lowe's/Home Despot and pick them up!
Took advantage of a contractor friend's discount to buy them from an (overpriced) electrical supply house, locally.
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On Thu, 03 Dec 2015 15:00:23 -0700, Don Y

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On Wed, 02 Dec 2015 13:43:52 -0700, Don Y

the lights - cold surge or not. How old are the light strings? Or the extension cords?
My strong suspicion is you have electrical leagage somewhere - the lights are shorting to ground (very high resistance), the cord is leaking to ground (very high resistance) or you have a leakage somewhere in the house wiring/outlets.
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On 12/2/2015 7:54 PM, snipped-for-privacy@snyder.on.ca wrote:

The strings are varying ages. It's not like we made note of when we got each set. Cords are probably 10 years old. They stay indoors except for this time of year.

Lights can't short to "ground" cuz they're only two wire devices (tree isn't a very good conductor when you consider the wires tend to lay on leaves)

Possible as its a 3 conductor extension.

Also possible. However, I don't consider any of those to be LIKELY!
I.e., why would it "leak" then NOT leak a second later (when power applied from the breaker).
And, when *hot*, not leak for 8 hours of continuous use; not leak after being disconnected for 1 second; not leak after being disconnected for 10 seconds; then "leak" when disconnected for 2 minutes??
I.e., what -- other than the temperature/resistance of the tungsten filaments -- is going to exhibit changes on the order of "many seconds" (something greater than 10 and less than 120)?
I wish I still had my Hi-Pot tester! :<
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On Wed, 02 Dec 2015 20:04:37 -0700, Don Y

at a leakage of 3 to 5 mA. At 4 mA, it may or may not trip. For whatever reason, when first turned on, its trip point is 3 mA (within spec) but it then rises to nearer 5 mA (still within spec). Wouldn't that explain what you are seeing? I made up those numbers, but you get the idea. Look for a small leakage of current from hot to ground (or a low resistance connection from neutral to ground) that is on the hairy edge of tripping the GFCI. As others have said, water or bugs in one of the boxes on the line is the most likely. A neutral to ground short in one of the boxes is also possible. Good luck. These things are not easy to find.
Pat
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On 12/3/2015 4:25 AM, Pat wrote:

Wait, what is "it" in each of your statements? The actual leakage current? Or, the *setpoint* -- the point DEFINED BY THE BREAKER -- at which the GFCI will open the circuit?
What causes it (whatever "it" may be) to rise?

Ha! That last nominated for Understatement of the Year! ;-)
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On Wed, 02 Dec 2015 20:04:37 -0700, Don Y

Leakge from deteriorated insulation to the leaves is all it takes to trip a GFCI - and the fact they "stick" on the second or third attempt means they could be just drying themselves out enough to reduce the leak enough to not trip the third time.

are holding the wire and causing the "leak"

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On 12/3/2015 2:39 PM, snipped-for-privacy@snyder.on.ca wrote:

Wouldn't explain why the other strings (alternate test load) tripped the breaker. They weren't *in* the tree.
Also wouldn't account for SWMBO's comment that *she* had had problem using the toaster oven on that circuit some months before.
"On grumbling about this ("yet another chore on my list") to SWMBO, she claims she took the toaster oven outdoors some months ago (WTF?) to "prepare" something and it wouldn't work, either."

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thats what main breakers are designed for, changing breakers in a hot panel is just plain dumb...
of course you have to reset clocks etc......
but you have to do that if your home has a power failure
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On 12/2/2015 9:05 PM, bob haller wrote:

Every panel I've ever been in makes it relatively easy to change a breaker with power on. The breakers typically clip into/onto one bus bar or the other (or both) so the "live" circuit is not anywhere near where you are working. Only a section of the bus bar(s) that you will be connecting to is exposed BETWEEN the other installed breakers. In our case, that means a slot 5/8" wide and 2+ inches deep to touch the bus bar.
The hot wire running off to the branch circuit can be connected *before* installing a breaker or disconnected *after* the breaker is pulled out.
By contrast, the GFCI's require a connection to the neutral bus. In our panel, that means exposing the AC line *at* the main breaker. Turning off the breaker gives you very little added protection -- slip and you're toast.

Generational differences? :> Sure, we'd have to reset a couple of bedroom clocks, HiFi's, oven, microwave, etc. And, coordinate our activities so we're not without power when we're expecting to do something (make dinner, watch a movie, etc.)
But, that's pretty easy.
The real effort comes with the computers that are undoubtedly running at the time of the "planned outage".
I'd have to make notes as to what I was doing on each of the computers that were powered up, at the time (assuming they aren't actively "doing something" that will take a fair amount of time -- like rendering a 3D model, "make world", etc.); examine each open application so I can return to that state when power is eventually restored.
(I typically leave a machine exactly where it was when I was last using it so the display reminds me as to what I was doing)
Also, shut down any network appliances or headless servers in an orderly manner. etc.
Or, hope the batteries in each UPS are stiff enough to carry the loads for the time you *expect* to need to swap out the breaker.
I.e., I have to do a fair bit of planning if I want to remove power for anything more than a few seconds (which I expect the UPS's to always handle even when batteries are toast).

I have no control over a power failure. I *do* have control over when -- and IF -- I remove power to do electrical maintenance!
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On Wed, 02 Dec 2015 23:02:47 -0700, Don Y

wouldn't stand a chance of passing code up here as a new install. NO conductors from the "switched" side are allowed into the "main" side of the panel. None. Period.
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On 12/3/2015 2:43 PM, snipped-for-privacy@snyder.on.ca wrote:

In addition to the expense and inconvenience, that opens up a whole can of worms. House is block so you can't move the box "an inch or two" to accommodate breakers in the new loadcenter being some different distance from where the wires come through the block.
Neighbor enhanced his service some years ago. A nightmare for him to "stretch" the wires to reach the new locations of the breakers. You roll the dice; if the wires don't reach, you're SoL (have to rerun the branch circuit).
Another neighbor had his panel catch fire (corroded mains). Same sort of issue -- can't just find "drop in" replacements for these sorts of things! (And, you're without power for the time it takes to tear down, install, rewire AND get inspected!)
"If it ain't broke, don't fix it!"
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