On 12/3/2015 2:36 PM, wrote:
On Wed, 02 Dec 2015 19:56:58 -0700, Don Y
wrote:

On 12/2/2015 7:35 PM, wrote:

What brand panel and breaker?

Old CH.
Bolt on or snap on? I've seen a lot of issues lately on the old CH
panels - (I'm talking from the '70s) - failing breakers and no direct
replacements - so guys put in the new ones and butcher the panel cover
to make them fit.

Meter center has KWHr meter and mains input on left side
(power feeds from below grade). Right side is just a
"load center".

Two bus bars run the length (height) of the panel, interleaving
the two "hot legs" (i.e., a double wide breaker ends up straddling
both legs).

Bus bars have large "tongues" that protrude at right angles above
the bars. Underside of breakers have a tight slot that grabs onto
this tongue. (other "end" of breaker has a lip that clips over
a metal/grounded mechanical support).

So, lift side of breaker that adheres to the tongue, pivoting on
the other side that is clipped behind that metal lip. Breaker
is then free to be removed -- save for any conductors that
are tied to it (e.g., neutral pigtail, neutral load and hot
load for GFCI; hot load for regular breaker)

Panel is at least 35 years old (so, I've been chasing down
NOS spares before they become unobtanium). But, everything is
still intact.

The GFCI's were purchased "new" many years ago. Note that
there are 5 in the panel; three of which see everyday use
(kitchen countertops plus bathrooms) and have never complained
(despite large loads -- toaster oven, electric frying pan,
hair dryers, etc.).

Fourth GFCI has just been "stored" in the panel. It was the
candidate that I exploited to replace the GFCI for this
outlet branch circuit.

I.e., too many coincidences wouold have to occur for me
to conclude it was a GFCI (*breaker*) problem.

shrug I'll look at it this weekend. I've got some candy
that I've got to make, today (while SWMBO is "away")

On Thu, 03 Dec 2015 09:45:28 -0700, Don Y
wrote:

On 12/3/2015 7:03 AM, wrote:

You do know that incandescent bulbs can pull about 10x the current on
turn on?

You do know that having 700W of incandescents on even a 15A circuit is
very common and doesn't cause breakers tripping?

OK...Lets talk details.

I don't know the details of the inards of GFI breakers. Maybe you do.

Lets say the COLD turn on surge is 20 Amps for a short time and that alone
is not enough to trip a 20 A breaker.

We know it isn't -- because I moved the extension cord to a non-GFCI circuit
and the circuit had no problem holding the load.

(We also know that in years past, a 15A-18A load had no problem on the
same GFCI circuit!)

Lets say there is also 3 mA of leakage and the trip point for the GFI
breaker is 5 mA so 3 mA alone is not enough to trip the breaker.

But what about both together? Maybe both together will trip.

I don't know. Clearly (?) there is something "GFCI-related" with the
current situation -- as a second GFCI breaker swapped in to replace the
original GFCI breaker is behaving exactly the same way.

I don't know if each trip point is totally seperate inside the breaker or
if they somehow are added. Do you? (I'm not trying to be snooty)

I don't. As I pointed out upthread, there's no guarantee that a
non-GFCI's current holding characteristics, response time, etc.
are the same as that of a GFCI breaker WITH THE GFCI PORTION DISABLED.

I do know that a truely COLD bulb turn on draws a bigger surge then one
where the bulbs have been pre warmed. It doesn't seem logical I agree, but
I have seen it. You have to wait a good number of seconds for the filament
to totally cool to get the full surge current.

Again, note the (apparently thermal) characteristics reported:
- breaker IMMEDIATELY trips when switched on with a "cold" load
(we'll leave the definition of "cold" vague, for now)
- seconds later, throwing the breaker holds, indefinitely
- "cold" lamps "plugged into" a live circuit immediately trip it
- lamps that have been on for hours can be unplugged and replugged
within 1 (or 10!) seconds and the circuit will hold
- lamps that have been allowed to "rest" for 2 minutes will immediately
trip the breaker

It sure *seems* like allowing things to "cool off" -- or, starting
with something "cold" -- is the differentiating aspect of the problem.

It doesn't seem like this small diffence should be the OPs problem but at
this point, who knows?

I agree with the suggestion to change to a non GFI breaker as a test to
eliminate the leakage part of the question.

Note that all this would do is isolate the "in wall wiring" as a potential
cause of an hypothesized GFCI issue. We've already tried a non-GFCI
branch circuit with the extension cord and lamps.

I'll try plugging the extension cord into a kitchen outlet (unloaded circuit)
as that would test a different GFCI with the existing extension cord
BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
existing extension cord and THE SAME WIRING).

[This is easy to do whereas tying the existing wiring to a nonGFCI
breaker is a significant effort]
What GFCI breakers are you using in that "old ch" panel??

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?

On Thu, 3 Dec 2015 09:01:23 -0800 (PST), wrote:

On Thursday, December 3, 2015 at 9:17:11 AM UTC-5, trader_4 wrote:
On Thursday, December 3, 2015 at 9:04:11 AM UTC-5, wrote:

You do know that incandescent bulbs can pull about
10x the current on turn on?

You do know that having 700W of incandescents on even a 15A
circuit is very common and doesn't cause breakers tripping?

OK...Lets talk details.

I don't know the details of the inards of GFI breakers. Maybe you do.

Lets say the COLD turn on surge is 20 Amps for a short time and that alone is not enough to trip a 20 A breaker.

Lets say there is also 3 mA of leakage and the trip point for the GFI breaker is 5 mA so 3 mA alone is not enough to trip the breaker.

But what about both together? Maybe both together will trip.

I don't know if each trip point is totally seperate inside the breaker or if they somehow are added. Do you? (I'm not trying to be snooty)


Yes, they are separate. The fault current is measured by comparing the
balance between the current in the hot and neutral and it trips
independently of the overall current. Adding wouldn't get you anywhere
because the fault current trip is three orders of magnitude smaller than
the load current trip.


Of course the currents are not added directly.
That is not what i meant.
5 mA is nothing compared to 20A.


I mean the trip forces in the mechanism might add.

If 19 Amps puts say 1 pound of force on the trip mechanism and 3 mA also puts one pound of force, then each alone might not trip it, but together they put 2 pounds of force which could be enough to trip it.

These are mechanical devices afterall.

Mark




I do know that a truely COLD bulb turn on draws a bigger surge then one where the bulbs have been pre warmed. It doesn't seem logical I agree, but I have seen it. You have to wait a good number of seconds for the filament to totally cool to get the full surge current.


I agree that cold bulbs will draw a lot more current initially.


It doesn't seem like this small diffence should be the OPs problem but at this point, who knows?

I agree with the suggestion to change to a non GFI breaker as a test to eliminate the leakage part of the question.

Mark

I thought he said he had done that and it worked without tripping?
On the Square D the 2 trip mechanisms are totally separate, and the
GFCI load section is the same as the non GFCI breaker. No idea what
breakers you have in the CH panel, but "generally" that is how they
are made.

On 12/03/2015 3:20 PM, Don Y wrote:
....

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*!)

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!!!!")

--

On 12/3/2015 2:33 PM, wrote:

On my QO panel it's easy - neutral buss on both sides. Putting in the
GFCI I had to extend the neutral because the sparky that replaced the
panel didn't run the neutrals for the breakers on the one side to the
same side as the breaker - he put all the neutrals on the "short"
side. VERY neet job - but made it difficult to install GFCI breakers
in the panel.

In our case, the ground/neutral bus is located on the meter side of
the panel. I.e., to gain access, you have to expose the AC mains
on the output of the meter connection/input to main disconnect/output
of main disconnect.

Of course, the bus bar is mounted against the rear of the panel,
so you have to reach *into* the panel (with screwdriver) to open
the lockdown screws in the bar. Then, reach in with your *fingers*
to thread the neutral wire (or, neutral pigtail!) under the
lockdown screw -- before tightening it.

So, all of the GFCI's must be located at the top of the loadcenter
side of the panel -- else their pigtails won't reach the grounding
bar! And, all the neutrals have to work their way up to the top
of the box where they can cross over to the meter side to tie into
the ground *and* neutral!

I.e., I don't like opening that side of the box! :

You can replace a breaker just by prying the "tongue" side loose.
Then, with the breaker IN YOUR HAND, you can leisurely remove the
hot conductor from it! (and neutral, if a GFCI). You don't have to
make any penetration into the box (and the bus bars waiting there!)

OTOH, if you opt to replace a GFCI with a non-GFCI, you now have
to figure out how to get the branch circuit's neutral over
to the meter side of the box!

(and, if you're only doing this to test a theory, you look for
other ways to garner that information that are less involved! : )

On 12/3/2015 2:34 PM, wrote:
On Wed, 02 Dec 2015 19:56:17 -0700, Don Y
wrote:

On 12/2/2015 7:45 PM, wrote:
Beyond that, I'll have to start opening wire nuts -- not something
I like doing with #12AWG :
Not aluminum, by chance??

God, no!

Just wondered with 12G - so they are 20 amp circuits - - -

Yes. Code requires them for kitchen countertop. etc. So, I
just installed a bunch of them (bathrooms, countertops, outdoor
and garage)

On 12/3/2015 2:47 PM, wrote:
On Thu, 03 Dec 2015 09:45:28 -0700, Don Y
wrote:

On 12/3/2015 7:03 AM, wrote:

You do know that incandescent bulbs can pull about 10x the current on
turn on?

You do know that having 700W of incandescents on even a 15A circuit is
very common and doesn't cause breakers tripping?

OK...Lets talk details.

I don't know the details of the inards of GFI breakers. Maybe you do.

Lets say the COLD turn on surge is 20 Amps for a short time and that alone
is not enough to trip a 20 A breaker.

We know it isn't -- because I moved the extension cord to a non-GFCI circuit
and the circuit had no problem holding the load.

(We also know that in years past, a 15A-18A load had no problem on the
same GFCI circuit!)

Lets say there is also 3 mA of leakage and the trip point for the GFI
breaker is 5 mA so 3 mA alone is not enough to trip the breaker.

But what about both together? Maybe both together will trip.

I don't know. Clearly (?) there is something "GFCI-related" with the
current situation -- as a second GFCI breaker swapped in to replace the
original GFCI breaker is behaving exactly the same way.

I don't know if each trip point is totally seperate inside the breaker or
if they somehow are added. Do you? (I'm not trying to be snooty)

I don't. As I pointed out upthread, there's no guarantee that a
non-GFCI's current holding characteristics, response time, etc.
are the same as that of a GFCI breaker WITH THE GFCI PORTION DISABLED.

I do know that a truely COLD bulb turn on draws a bigger surge then one
where the bulbs have been pre warmed. It doesn't seem logical I agree, but
I have seen it. You have to wait a good number of seconds for the filament
to totally cool to get the full surge current.

Again, note the (apparently thermal) characteristics reported:
- breaker IMMEDIATELY trips when switched on with a "cold" load
(we'll leave the definition of "cold" vague, for now)
- seconds later, throwing the breaker holds, indefinitely
- "cold" lamps "plugged into" a live circuit immediately trip it
- lamps that have been on for hours can be unplugged and replugged
within 1 (or 10!) seconds and the circuit will hold
- lamps that have been allowed to "rest" for 2 minutes will immediately
trip the breaker

It sure *seems* like allowing things to "cool off" -- or, starting
with something "cold" -- is the differentiating aspect of the problem.

It doesn't seem like this small diffence should be the OPs problem but at
this point, who knows?

I agree with the suggestion to change to a non GFI breaker as a test to
eliminate the leakage part of the question.

Note that all this would do is isolate the "in wall wiring" as a potential
cause of an hypothesized GFCI issue. We've already tried a non-GFCI
branch circuit with the extension cord and lamps.

I'll try plugging the extension cord into a kitchen outlet (unloaded circuit)
as that would test a different GFCI with the existing extension cord
BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
existing extension cord and THE SAME WIRING).

[This is easy to do whereas tying the existing wiring to a nonGFCI
breaker is a significant effort]
What GFCI breakers are you using in that "old ch" panel??

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?

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.

[snip]

So, "two strings of three". Each string has 25 (?) 9W (nominal) lamps
so ~225W/string or 675W per string-of-3; 1350W for the pair of these.

C9 lights? The 9 is the size of the bulb (I think 9mm across). IIRC
power consumption is 7W.

[snip]

--
22 days until the winter celebration (Friday December 25, 2015 12:00:00
AM for 1 day).

Mark Lloyd
http://notstupid.us/

"The man who wants to be an angel is never in a hurry to begin." [Lemuel
K. Washburn, _Is The Bible Worth Reading And Other Essays_]

On 12/3/2015 3:12 PM, Mark Lloyd wrote:

[snip]

So, "two strings of three". Each string has 25 (?) 9W (nominal) lamps
so ~225W/string or 675W per string-of-3; 1350W for the pair of these.

C9 lights? The 9 is the size of the bulb (I think 9mm across). IIRC power
consumption is 7W.

Dunno. The "9" stuck in my mind. They are the "really big" incandescents
(not to be confused with the smaller 4W and 7W (identical to the 4W
in size) "night lights" you'd encounter in a house.

[I don't have any spare bulbs in store-bought packages; and the actual
strings get stored in shoebox sized boxes (that aren't actually for
shoes) cuz it's impractical to try to cram them back into the
boxes in which they originally were purchased).]

For other incandescents, often the wattage is stamped in the metal
screw base. I should see if I can read anything (that small) there...

The outlets in the back of the house are on a 20A GFCI.
(Note to self: are there any other outlets on that same
circuit that I need to chase down?)

Presently using them to light XMAS lights on one of the
citrus trees. IIRC, each string is about 250W. With
~700W on the circuit, turning the breaker ON (i.e., using
it as a switch -- instead of plugging/unplugging the
load) causes it to immediately trip. Repeating the
action in short order appears to get it to latch and
remain latched (ON), indefinitely.

OK, so the surge when all the lamps are cold can increase
the inrush current -- on the short term -- to levels that
probably exceed the 20A limit of the breaker.

"In theory"

OTOH, in years past, I've run the circuit at close to its
capacity (~10 strings) without this problem.

I've changed breakers (swapped with one feeding another
circuit) and the problem persists.

[There are no leakage paths in the wiring OUTSIDE]

This suggests something in the wiring/fixtures. I'll
start isolating outlets, tomorrow (dark here, now).
Perhaps some insect (leaf cutter?) has opted to nest
in one of the receptacles.

Anything else I should explore?


Many many years ago I worked as an electrician in a hospital that had an indoor pool. Every day when the attendant turned on the Metal Halide HID overhead lights over the pool deck, the GFCI circuit breakers would trip. I changed the breakers and tighten the connections, but the symptoms never went away. When the circuit breakers were reset, the lights stayed on until the pool closed when they were then intentionally shut off. The next day would bring the same symptoms. I had surmised that perhaps the high humidity environment was causing condensation on the ballasts, but that was just a best guess. After a while I gave up and just made it my business to turn on the pool lights every day.

John Grabowski
http://www.MrElectrician.TV

On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
wrote:

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.

If I was really willing to "diagnose" this I would get a device type
GFCI, Disable the trip mechanism and look at the output of the
differential amplifier with a scope as I plugged in the lights, cords
etc looking for the one that is the offender. You could calibrate your
result using a pot and introducing a known fault value.
My bet is you will see this thing cruising in the 3-4 ma range so any
little glitch pushes it over.

On Thursday, December 3, 2015 at 7:47:53 PM UTC-5, wrote:
On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
wrote:

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.


I always start on the path of trying to fully diagnose the problem
instead of swapping parts. But anyone who has worked on cars has sure
had many times where they wished they had the dealers stock of parts
to try swapping something that is easily swappable to see if it fixes it.


If I was really willing to "diagnose" this I would get a device type
GFCI, Disable the trip mechanism and look at the output of the
differential amplifier with a scope as I plugged in the lights, cords
etc looking for the one that is the offender. You could calibrate your
result using a pot and introducing a known fault value.
My bet is you will see this thing cruising in the 3-4 ma range so any
little glitch pushes it over.

Agree, that's the problem and why you're left with swapping. To conduct
the required tests is going to require some advanced gear that homeowner's
typically don't have. Even if I had it or had access to it, I wouldn't
waste my time trying to figure it out.

On 12/3/2015 2:43 PM, wrote:
On Wed, 02 Dec 2015 23:02:47 -0700, Don Y
wrote:

On 12/2/2015 9:05 PM, bob haller wrote:

[I'm comfortable working with electricity -- but in the panel, there's
nothing between you and "sudden death" : I'm not going to flip the main
breaker just to make these sorts of breaker changes]

thats what main breakers are designed for, changing breakers in a hot panel
is just plain dumb...

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.

of course you have to reset clocks etc......

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).

but you have to do that if your home has a power failure

I have no control over a power failure. I *do* have control
over when -- and IF -- I remove power to do electrical
maintenance!
If it's the "Old CH" I'm thinking of, I'd be replacing it. It
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.

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!"

On 12/3/2015 2:40 PM, wrote:
On Wed, 2 Dec 2015 20:05:12 -0800 (PST), bob haller
wrote:

[I'm comfortable working with electricity -- but in the panel,
there's nothing between you and "sudden death" : I'm not
going to flip the main breaker just to make these sorts
of breaker changes]

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
On a square D QO panel you'd have to be pretty stupid to shock
yourself changing a breaker with the panel "live". Like you'd almost
have to TRY.

"Stupid" may be a bit harsh. But, if you're not doing this sort of
thing on a daily basis, it's easy to get focused on WHAT you are
trying to do and forget HOW you should be doing it!!

When I was in school, I had to make some wiring changes to a
friend's vehicle. Had soldering station sitting out on his
vehicle (hood or trunk, I can't recall).

Realized the tip I was using was too small to convey enough heat to
the work. Not keen on waiting for it to cool off...

Didn't have a rag handy to grasp it...

So, lifted my leg to use the fabric of my jeans (down by my ankle)
to grab the tip and unscrew it. Then, holding the tip in my
pant leg, lifted my ankle even higher to drop the (hot!) tip
on the bumper. Set my leg back down -- tickled that I'd managed
to do this without falling over -- and promptly picked up the tip
with my right hand to place it in my *pocket*!

Of course, it never made it *to* my pocket. The sound of searing flesh
was unmistakeable.

My buddy just looked at me and said, "I can't believe -- after that
elaborate *dance* that you just did (to avoid touching the hot
tip) -- that you just grabbed that!"

shrug Too preoccupied with trying NOT to fall over that I'd
forgotten WHY this had been necessary! :

On 12/3/2015 2:39 PM, wrote:
On Wed, 02 Dec 2015 20:04:37 -0700, Don Y
wrote:

On 12/2/2015 7:54 PM, wrote:

I think you can pretty definitevly rule out tripping from the load of
the lights - cold surge or not.
How old are the light strings? Or the extension cords?

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.

My strong suspicion is you have electrical leagage somewhere - the
lights are shorting to ground (very high resistance),

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)

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.

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."

a 5ma leak is low enough you generally will not even feel it if you
are holding the wire and causing the "leak"
the cord is
leaking to ground (very high resistance)

Possible as its a 3 conductor extension.

or you have a leakage
somewhere in the house wiring/outlets.

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! :

On 12/3/2015 5:18 PM, John G wrote:

Many many years ago I worked as an electrician in a hospital that had an
indoor pool. Every day when the attendant turned on the Metal Halide HID
overhead lights over the pool deck, the GFCI circuit breakers would trip. I

You haven't explicitly said it (and, as I suspect they are considerably
ABOVE the pool, it might not be required?) but were teh HID's the load
that the GFCI(s) were protecting? Or, were there other GFCI circuits
and the "noise" (?) from the HID's interfering with them?

changed the breakers and tighten the connections, but the symptoms never
went away. When the circuit breakers were reset, the lights stayed on until
the pool closed when they were then intentionally shut off. The next day

So, that's the same behavior I'm reporting? I.e., first ("cold") attempt
to turn on causes breaker to trip (i.e., before it ever latches!). But,
immediately thereafter, a subsequent attempt to turn on works properly?

would bring the same symptoms. I had surmised that perhaps the high humidity
environment was causing condensation on the ballasts, but that was just a

How soon after the first failure would you reattempt? Would it seem
logical that any condensate would/could evaporate in that time?
(i.e., not liquid water, perhaps, but "dampness"?)

best guess. After a while I gave up and just made it my business to turn on
the pool lights every day.

I will return to a more structure testing "program" this weekend
(assuming nothing else rises to the top of the Honey-Do's). Among
other things, I'd like to know if, once "holding", the crcuit
will actually hold its full rated load. Or, if there is yet
another set of symptoms to add to the list...

On Thu, 03 Dec 2015 15:00:23 -0700, Don Y
wrote:

On 12/3/2015 2:47 PM, wrote:
On Thu, 03 Dec 2015 09:45:28 -0700, Don Y
wrote:

On 12/3/2015 7:03 AM, wrote:

You do know that incandescent bulbs can pull about 10x the current on
turn on?

You do know that having 700W of incandescents on even a 15A circuit is
very common and doesn't cause breakers tripping?

OK...Lets talk details.

I don't know the details of the inards of GFI breakers. Maybe you do.

Lets say the COLD turn on surge is 20 Amps for a short time and that alone
is not enough to trip a 20 A breaker.

We know it isn't -- because I moved the extension cord to a non-GFCI circuit
and the circuit had no problem holding the load.

(We also know that in years past, a 15A-18A load had no problem on the
same GFCI circuit!)

Lets say there is also 3 mA of leakage and the trip point for the GFI
breaker is 5 mA so 3 mA alone is not enough to trip the breaker.

But what about both together? Maybe both together will trip.

I don't know. Clearly (?) there is something "GFCI-related" with the
current situation -- as a second GFCI breaker swapped in to replace the
original GFCI breaker is behaving exactly the same way.

I don't know if each trip point is totally seperate inside the breaker or
if they somehow are added. Do you? (I'm not trying to be snooty)

I don't. As I pointed out upthread, there's no guarantee that a
non-GFCI's current holding characteristics, response time, etc.
are the same as that of a GFCI breaker WITH THE GFCI PORTION DISABLED.

I do know that a truely COLD bulb turn on draws a bigger surge then one
where the bulbs have been pre warmed. It doesn't seem logical I agree, but
I have seen it. You have to wait a good number of seconds for the filament
to totally cool to get the full surge current.

Again, note the (apparently thermal) characteristics reported:
- breaker IMMEDIATELY trips when switched on with a "cold" load
(we'll leave the definition of "cold" vague, for now)
- seconds later, throwing the breaker holds, indefinitely
- "cold" lamps "plugged into" a live circuit immediately trip it
- lamps that have been on for hours can be unplugged and replugged
within 1 (or 10!) seconds and the circuit will hold
- lamps that have been allowed to "rest" for 2 minutes will immediately
trip the breaker

It sure *seems* like allowing things to "cool off" -- or, starting
with something "cold" -- is the differentiating aspect of the problem.

It doesn't seem like this small diffence should be the OPs problem but at
this point, who knows?

I agree with the suggestion to change to a non GFI breaker as a test to
eliminate the leakage part of the question.

Note that all this would do is isolate the "in wall wiring" as a potential
cause of an hypothesized GFCI issue. We've already tried a non-GFCI
branch circuit with the extension cord and lamps.

I'll try plugging the extension cord into a kitchen outlet (unloaded circuit)
as that would test a different GFCI with the existing extension cord
BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
existing extension cord and THE SAME WIRING).

[This is easy to do whereas tying the existing wiring to a nonGFCI
breaker is a significant effort]
What GFCI breakers are you using in that "old ch" panel??

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?

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.

Lots of scrounging - lots of fun.

On Thu, 03 Dec 2015 18:17:46 -0700, Don Y
wrote:


If it's the "Old CH" I'm thinking of, I'd be replacing it. It
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.

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.


That's where you have to do your homework. I made sure the panel I
purchased would fit. A few applications of the greenley punch - I
didn't have to move a single wire - and all the wires were long enough
to reach, after sorting out what went where.

If I had let the electrician supply the panel he usually uses there
would have been a few junction boxes involved - and that I did NOT
want!!!!
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).

Or install a "stretcher box" - a surface mounted junction box to
splice the wires. Nasty - but it works, passes code, and is not
difficult.

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!"

This is where I differ. I say fix it while it is fixable - and on your
schedule. Letting the panel decide when it has to be replaced never
works out in your favour.

On Thu, 03 Dec 2015 18:25:34 -0700, Don Y
wrote:

On 12/3/2015 2:40 PM, wrote:
On Wed, 2 Dec 2015 20:05:12 -0800 (PST), bob haller
wrote:

[I'm comfortable working with electricity -- but in the panel,
there's nothing between you and "sudden death" : I'm not
going to flip the main breaker just to make these sorts
of breaker changes]

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
On a square D QO panel you'd have to be pretty stupid to shock
yourself changing a breaker with the panel "live". Like you'd almost
have to TRY.

"Stupid" may be a bit harsh. But, if you're not doing this sort of
thing on a daily basis, it's easy to get focused on WHAT you are
trying to do and forget HOW you should be doing it!!

The QO panel has a "sheilded" bus - you need to stick your finger in
to touch it - I'll stick with "stupid" - or "extremely careless" -
which when working around electricity IS "stupid"

When I was in school, I had to make some wiring changes to a
friend's vehicle. Had soldering station sitting out on his
vehicle (hood or trunk, I can't recall).

Realized the tip I was using was too small to convey enough heat to
the work. Not keen on waiting for it to cool off...

Didn't have a rag handy to grasp it...

So, lifted my leg to use the fabric of my jeans (down by my ankle)
to grab the tip and unscrew it. Then, holding the tip in my
pant leg, lifted my ankle even higher to drop the (hot!) tip
on the bumper. Set my leg back down -- tickled that I'd managed
to do this without falling over -- and promptly picked up the tip
with my right hand to place it in my *pocket*!

Of course, it never made it *to* my pocket. The sound of searing flesh
was unmistakeable.

My buddy just looked at me and said, "I can't believe -- after that
elaborate *dance* that you just did (to avoid touching the hot
tip) -- that you just grabbed that!"

shrug Too preoccupied with trying NOT to fall over that I'd
forgotten WHY this had been necessary! :

On Thu, 3 Dec 2015 17:16:03 -0800 (PST), trader_4
wrote:

On Thursday, December 3, 2015 at 7:47:53 PM UTC-5, wrote:
On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
wrote:

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.


I always start on the path of trying to fully diagnose the problem
instead of swapping parts. But anyone who has worked on cars has sure
had many times where they wished they had the dealers stock of parts
to try swapping something that is easily swappable to see if it fixes it.


When I was fixing things for a living, my first question on a support
call was asking the guy who was working on it "Can you draw a circle
around the problem"? (in an acre of computer room floor, that may not
be as simple as it sounds)

Until you know for sure what box is failing, you really have to back
up and reassess.

It was surprising how many times that just getting your head put of
the box, turned a light on and got you on the right track.
Isolating the problem does not mean simply throwing parts at it. You
should learn something at each step.

In Don's situation,. I would start with a configuration that doesn't
fail and keep adding stuff until you break it.
Drag a known good space heater or heat gun out to the end of that
extension cord and try that, bearing in mind, the fault could be on
the neutral and that will not fail without a load.

On 12/3/2015 8:25 PM, wrote:
On Thu, 3 Dec 2015 17:16:03 -0800 (PST), trader_4
wrote:

On Thursday, December 3, 2015 at 7:47:53 PM UTC-5, wrote:
On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
wrote:

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.


I always start on the path of trying to fully diagnose the problem
instead of swapping parts. But anyone who has worked on cars has sure
had many times where they wished they had the dealers stock of parts
to try swapping something that is easily swappable to see if it fixes it.


When I was fixing things for a living, my first question on a support
call was asking the guy who was working on it "Can you draw a circle
around the problem"? (in an acre of computer room floor, that may not
be as simple as it sounds)

Until you know for sure what box is failing, you really have to back
up and reassess.

It was surprising how many times that just getting your head put of
the box, turned a light on and got you on the right track.
Isolating the problem does not mean simply throwing parts at it. You
should learn something at each step.

In Don's situation,. I would start with a configuration that doesn't
fail and keep adding stuff until you break it.
Drag a known good space heater or heat gun out to the end of that
extension cord and try that, bearing in mind, the fault could be on
the neutral and that will not fail without a load.

There are no configurations that "don't fail" -- except the configuration
where there is no load present (and, thus, no need for power!).

My approach will be the opposite: remove things until it starts working.

Recall, everything worked last year. The extension cords and lights
have been stored "indoors" for all that time. OTOH, the outlets have been
exposed to the elements for the ~9 months (including a Summer and a Monsoon)
since then. So, any "changes" are most likely manifest in those items!

Wiring inside the block wall is likely not at risk as it is safely
hidden away (unless something likes chewing on vinyl!)

First, verify SWMBO's assertion that the toaster oven resulted in a similar
behavior. If that's true, it *tends* to rule out the lights and the
extension cord as possible problem areas (no guarantee, there, as they
could have other problems, as well). Then, reattach the lights as
the "nominal load" -- cuz I have lots of experience with them failing
(I don't want to end up with a situation where things SOMETIMES work
and that confuses any deductions made later).

[The idea of leaving an item used for food prep outside just doesn't
appeal to me! : ]

Explore the upper limits on what the breaker will HOLD. If it trips
(when it would otherwise have held, based on prior observations),
I have another data point regarding the circuit's performance.
Is any loss of capacity a likely effect of aging? Or, is it dramatic
enough to suggest a fault, somewhere (keeping in mind that I'm
using the replacement GFCI, presently). Can a regular (20A) branch circuit
carry the same load without incident? (those breakers are OLDER, yet!)

Then, open all the Jboxes and have a peek inside. Any signs of "wildlife"?
Moisture?

Beginning at the box closest (electrically) to the panel, look at hot-neutral,
hot-ground, neutral-ground voltages under that fixed load (with breaker
in the "holding" state). Any IR drops should scale linearly; regardless of
how much wire there is between Jbox #X and Jbox #Y, there should be an
identical amount of neutral, hot and earth conductors! I can do this
from the exposed side of each receptacle -- no real effort required.

Then, start removing receptacles (in the hope that something may have set
up shop INSIDE one). At the same time, examine the contacts on each:
anything loose? Any signs of oxidation/corrosion?

Any changes in voltage readings when probing conductors instead of
outlet contacts?

Ultimately, I'll have to remove the outlet into which the extension
is plugged.

If this turns up nothing, start moving the load upstream. And, after
verifying operation at each such point, isolate the downstream
portion of the branch circuit (open wire nuts).

Eventually, I'll have a wire in the wall that connects the GFCI
to the *first* -- and ONLY -- receptacle.

On 12/3/2015 5:47 PM, wrote:
On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
wrote:

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.

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!)

If I was really willing to "diagnose" this I would get a device type
GFCI, Disable the trip mechanism and look at the output of the
differential amplifier with a scope as I plugged in the lights, cords
etc looking for the one that is the offender. You could calibrate your
result using a pot and introducing a known fault value.
My bet is you will see this thing cruising in the 3-4 ma range so any
little glitch pushes it over.

On Thu, 03 Dec 2015 23:22:41 -0700, Don Y
wrote:

There are no configurations that "don't fail" -- except the configuration
where there is no load present (and, thus, no need for power!).

So if you plug something into the outlet right next to the house it
fails?

On 12/3/2015 11:30 PM, wrote:
On Thu, 03 Dec 2015 23:22:41 -0700, Don Y
wrote:

There are no configurations that "don't fail" -- except the configuration
where there is no load present (and, thus, no need for power!).

So if you plug something into the outlet right next to the house it
fails?

(All of the outlets are "on" the house; presumably, you
meant "closest to the electric panel"?)

I've not tested each of the 5 outlets. They are spread over the
length of the house -- as well as around the side. I.e., I'd
have to *lengthen* the extension cord to reach them all.

I don't plan on continuing the "willy nilly" approach of jumping to
"try this", "now try that". Instead, I will approach the problem in
a more structured manner -- so each result adds to the data set
in a more organized fashion (instead of taking pot shots in different
areas).

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

On 12/3/2015 8:10 PM, wrote:
On Thu, 03 Dec 2015 18:17:46 -0700, Don Y
wrote:

If it's the "Old CH" I'm thinking of, I'd be replacing it. It
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.

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.

That's where you have to do your homework. I made sure the panel I
purchased would fit. A few applications of the greenley punch - I
didn't have to move a single wire - and all the wires were long enough
to reach, after sorting out what went where.

Of course it's do-able. The question is one of where that sits on the
list of things that *must* get done and *should* get done.

The decorative lintels over the garage and all windows will need to
be replaced. Cracks in the stucco need to be patched. Both of these
before I can paint the house.

We'll need to give some serious consideration to replacing the roof
in the next year or two.

SWMBO wants to replace some more windows in the front of the house.

I want to install a french drain along the back side of the house
to harvest rainwater -- and a large cistern to store it.

We've yet to select the water softener.

And, I still have a lot of automation to design and install.

Replacing an electric panel that isn't causing any problems
sure seems like ASKING for work!

If I had let the electrician supply the panel he usually uses there
would have been a few junction boxes involved - and that I did NOT
want!!!!
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).

Or install a "stretcher box" - a surface mounted junction box to
splice the wires. Nasty - but it works, passes code, and is not
difficult.

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!"

This is where I differ. I say fix it while it is fixable - and on your
schedule. Letting the panel decide when it has to be replaced never
works out in your favour.

We've seen one panel "fail" in the neighborhood -- due to corrosion
on the feed. Every other panel-related activity has been "elective"
or mandated by tariff changes from the utility. All the homes
were built within a year or two of each other so all "suffer"
the same sort of wear. If there was a pending problem, it;s
likely we'd be seeing some signs of it *somewhere* in the
neighborhood.

[I walk the entire neighborhood -- 3.8 mile loop -- daily. So,
interact with folks in enough different areas to have a pretty
good feel for what sorts of problems people are having. I can
tell you who's had plumbing problems, who's had their furnaces
replaced, who's had problem with their PV arrays, who's water
meters have failed, who's had pipes freeze, etc. While some
folks are interested in the salacious trivia, I'm more concerned
with things that are likely to cause me problems down the road;
things I can anticipate before they force me to act! : ]

A partial short between the ground and the neutral in the extension cord or elsewhere could cause the OPs symptoms.

Mark

On 12/4/2015 7:11 AM, wrote:

A partial short between the ground and the neutral in the extension cord or
elsewhere could cause the OPs symptoms.

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.

On Fri, 04 Dec 2015 05:00:33 -0700, Don Y
wrote:

On 12/3/2015 11:30 PM, wrote:
On Thu, 03 Dec 2015 23:22:41 -0700, Don Y
wrote:

There are no configurations that "don't fail" -- except the configuration
where there is no load present (and, thus, no need for power!).

So if you plug something into the outlet right next to the house it
fails?

(All of the outlets are "on" the house; presumably, you
meant "closest to the electric panel"?)

I've not tested each of the 5 outlets. They are spread over the
length of the house -- as well as around the side. I.e., I'd
have to *lengthen* the extension cord to reach them all.

I don't plan on continuing the "willy nilly" approach of jumping to
"try this", "now try that". Instead, I will approach the problem in
a more structured manner -- so each result adds to the data set
in a more organized fashion (instead of taking pot shots in different
areas).

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.

On Fri, 04 Dec 2015 13:12:26 -0700, Don Y
wrote:

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.


For the purposes if this discussion, a hair dryer would do just fine.
If it trips, you know you have a problem in the wall or receptacle
string. Then try it at the end of the extension cord. If still no
trip, there is a problem with your lights.

The idea that an incandescent light will trip a GFCI in normal
operation (no faults) is ludicrous. That tiny surge while the filament
is heating up is well inside the trip curve of any breaker I have ever
seen. It would certainly be less than the heat up time of a hair dryer
element.

On Friday, December 4, 2015 at 10:10:29 AM UTC-5, Don Y wrote:
On 12/4/2015 7:11 AM, wrote:

A partial short between the ground and the neutral in the extension cord or
elsewhere could cause the OPs symptoms.

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.


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.

On 12/4/2015 1:43 PM, wrote:
On Fri, 04 Dec 2015 13:12:26 -0700, Don Y
wrote:

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.

For the purposes if this discussion, a hair dryer would do just fine.
If it trips, you know you have a problem in the wall or receptacle
string. Then try it at the end of the extension cord. If still no
trip, there is a problem with your lights.

You've not been paying attention to the numerous "experiments"
I've already conducted.

E.g., different extension cord -- trips. Different light strings (same
cord) -- trips. Different GFCI breaker (same branch circuit) same
extension cord, same lights -- trips. "Cold" lights -- trips.
"Warm" lights -- no trip.

Extension + cold lights plugged into non-GFCI branch circuit -- *no* trip.
Ditto for different GFCI branch circuit, no trip.

I.e., nothing wrong with extension cord *or* lights.

Toaster oven (reported by SWMBO) plugged into same outlet WITHOUT extension
cord -- trips.

Problem is *clearly* with the wiring in the wall -- the only thing common
to all fault cases and NOT present in any of the non-fault cases! And,
only manifests when a load is present. Furthermore, only when the load is
significant ("cold" lamp strings)

The idea that an incandescent light will trip a GFCI in normal
operation (no faults) is ludicrous.

The whole point of the discussion is that there *is* a fault!
Note that a much larger load (3X) had been present on the same branch
circuit last Winter with *no* problems for the entire season!

That tiny surge while the filament
is heating up is well inside the trip curve of any breaker I have ever
seen. It would certainly be less than the heat up time of a hair dryer
element.

Forecast was for a cold night, tonight. So, rushed to get *something*
working -- regardless of an "explanation" -- in the hour I had before
sunset.

As it was obvious that the problem had to be in the branch circuit,
I removed all receptacles, examined the routing of the conductors
within each Jbox, inspected all wire nuts, screw terminals, grounds,
etc. and, then, reassembled everything. Washed the "wet use" covers
just to make things look pretty (continuous sun exposure turns the
exterior paint to a powdery substance).

No "obvious" problems: no "bugs" falling out of the receptacles, no
corrosion on terminals, no exposed wires under wire nut skirts, no
nicks in insulation, no moisture in boxes, no mounting screws pressing
on conductors, no cables pinched in clamps, plenty of room in each box
(35 cu in), etc.

Circuit has been holding without any problem -- even in the (unexpected!)
rain that's been falling (and the "false alarm" for the cold weather!).
Added another 2 strands of lights (with a second extension cord) just
to push my luck...

Took the (inexpensive -- $1) precaution of fitting "child proof" plugs to
all unused outlets to ensure nothing *can* crawl into any of the outlets
in the future.

No way to ensure I can recreate the problem -- as I have no idea
what it *actually* was -- so I'll leave well enough alone and wait
for the next hiccup. Maybe buy some 20A receptacles to replace
these when I next have to go poking around in the Jboxes...

Case closed.

On 12/12/2015 3:11 AM, Don Y wrote:
On 12/4/2015 1:43 PM, wrote:
On Fri, 04 Dec 2015 13:12:26 -0700, Don Y
wrote:

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast
suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.

For the purposes if this discussion, a hair dryer would do just fine.
If it trips, you know you have a problem in the wall or receptacle
string. Then try it at the end of the extension cord. If still no
trip, there is a problem with your lights.

You've not been paying attention to the numerous "experiments"
I've already conducted.

E.g., different extension cord -- trips. Different light strings (same
cord) -- trips. Different GFCI breaker (same branch circuit) same
extension cord, same lights -- trips. "Cold" lights -- trips.
"Warm" lights -- no trip.

Extension + cold lights plugged into non-GFCI branch circuit -- *no* trip.
Ditto for different GFCI branch circuit, no trip.

I.e., nothing wrong with extension cord *or* lights.

Toaster oven (reported by SWMBO) plugged into same outlet WITHOUT extension
cord -- trips.

Problem is *clearly* with the wiring in the wall -- the only thing common
to all fault cases and NOT present in any of the non-fault cases! And,
only manifests when a load is present. Furthermore, only when the load is
significant ("cold" lamp strings)

The idea that an incandescent light will trip a GFCI in normal
operation (no faults) is ludicrous.

The whole point of the discussion is that there *is* a fault!
Note that a much larger load (3X) had been present on the same branch
circuit last Winter with *no* problems for the entire season!

That tiny surge while the filament
is heating up is well inside the trip curve of any breaker I have ever
seen. It would certainly be less than the heat up time of a hair dryer
element.

Forecast was for a cold night, tonight. So, rushed to get *something*
working -- regardless of an "explanation" -- in the hour I had before
sunset.

As it was obvious that the problem had to be in the branch circuit,
I removed all receptacles, examined the routing of the conductors
within each Jbox, inspected all wire nuts, screw terminals, grounds,
etc. and, then, reassembled everything. Washed the "wet use" covers
just to make things look pretty (continuous sun exposure turns the
exterior paint to a powdery substance).

No "obvious" problems: no "bugs" falling out of the receptacles, no
corrosion on terminals, no exposed wires under wire nut skirts, no
nicks in insulation, no moisture in boxes, no mounting screws pressing
on conductors, no cables pinched in clamps, plenty of room in each box
(35 cu in), etc.

Circuit has been holding without any problem -- even in the (unexpected!)
rain that's been falling (and the "false alarm" for the cold weather!).
Added another 2 strands of lights (with a second extension cord) just
to push my luck...

Took the (inexpensive -- $1) precaution of fitting "child proof" plugs to
all unused outlets to ensure nothing *can* crawl into any of the outlets
in the future.

No way to ensure I can recreate the problem -- as I have no idea
what it *actually* was -- so I'll leave well enough alone and wait
for the next hiccup. Maybe buy some 20A receptacles to replace
these when I next have to go poking around in the Jboxes...

Case closed.

Perhaps something wasn't plugged all the way in and you fixed it when
you checked everything?

--
Maggie

On Sat, 12 Dec 2015 10:25:30 -0600, Muggles
wrote:

On 12/12/2015 3:11 AM, Don Y wrote:
On 12/4/2015 1:43 PM, wrote:
On Fri, 04 Dec 2015 13:12:26 -0700, Don Y
wrote:

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast
suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.

For the purposes if this discussion, a hair dryer would do just fine.
If it trips, you know you have a problem in the wall or receptacle
string. Then try it at the end of the extension cord. If still no
trip, there is a problem with your lights.

You've not been paying attention to the numerous "experiments"
I've already conducted.

E.g., different extension cord -- trips. Different light strings (same
cord) -- trips. Different GFCI breaker (same branch circuit) same
extension cord, same lights -- trips. "Cold" lights -- trips.
"Warm" lights -- no trip.

Extension + cold lights plugged into non-GFCI branch circuit -- *no* trip.
Ditto for different GFCI branch circuit, no trip.

I.e., nothing wrong with extension cord *or* lights.

Toaster oven (reported by SWMBO) plugged into same outlet WITHOUT extension
cord -- trips.

Problem is *clearly* with the wiring in the wall -- the only thing common
to all fault cases and NOT present in any of the non-fault cases! And,
only manifests when a load is present. Furthermore, only when the load is
significant ("cold" lamp strings)

The idea that an incandescent light will trip a GFCI in normal
operation (no faults) is ludicrous.

The whole point of the discussion is that there *is* a fault!
Note that a much larger load (3X) had been present on the same branch
circuit last Winter with *no* problems for the entire season!

That tiny surge while the filament
is heating up is well inside the trip curve of any breaker I have ever
seen. It would certainly be less than the heat up time of a hair dryer
element.

Forecast was for a cold night, tonight. So, rushed to get *something*
working -- regardless of an "explanation" -- in the hour I had before
sunset.

As it was obvious that the problem had to be in the branch circuit,
I removed all receptacles, examined the routing of the conductors
within each Jbox, inspected all wire nuts, screw terminals, grounds,
etc. and, then, reassembled everything. Washed the "wet use" covers
just to make things look pretty (continuous sun exposure turns the
exterior paint to a powdery substance).

No "obvious" problems: no "bugs" falling out of the receptacles, no
corrosion on terminals, no exposed wires under wire nut skirts, no
nicks in insulation, no moisture in boxes, no mounting screws pressing
on conductors, no cables pinched in clamps, plenty of room in each box
(35 cu in), etc.

Circuit has been holding without any problem -- even in the (unexpected!)
rain that's been falling (and the "false alarm" for the cold weather!).
Added another 2 strands of lights (with a second extension cord) just
to push my luck...

Took the (inexpensive -- $1) precaution of fitting "child proof" plugs to
all unused outlets to ensure nothing *can* crawl into any of the outlets
in the future.

No way to ensure I can recreate the problem -- as I have no idea
what it *actually* was -- so I'll leave well enough alone and wait
for the next hiccup. Maybe buy some 20A receptacles to replace
these when I next have to go poking around in the Jboxes...

Case closed.

Perhaps something wasn't plugged all the way in and you fixed it when
you checked everything?

More likely that there was a neutral fault that was cleared when he
pulled everything apart and put it back.
Lots of mystery GFCI problems are fixed by an inspection that didn't
actually find a problem. Who knows what it was?

On Sat, 12 Dec 2015 12:37:50 -0500, wrote:

On Sat, 12 Dec 2015 10:25:30 -0600, Muggles
wrote:

On 12/12/2015 3:11 AM, Don Y wrote:
On 12/4/2015 1:43 PM, wrote:
On Fri, 04 Dec 2015 13:12:26 -0700, Don Y
wrote:

On 12/4/2015 8:28 AM, wrote:

But, that will wait until at least the weekend. I have many other
things that need to get done in the short term and the forecast
suggests
I've got at least a week before temperatures begin to approach the
lows that are troublesome...

You can't get more "structured" that just plugging a comparable load
into the receptacle that fails (without involving extension cords tree
lights etc)

What if the nature of the load has an impact on the results?
E.g., say I plug a large power supply for that has an insane
turn-on transient in but idles at just a few watts (switching
losses). Smaller load but bigger turn on transient.

Or, drag out a longer spool of wire to use as the extension cord?

Or, try the toaster oven on one and lights on another?

Don't add variables to the analysis. Just come up with a
consistent test strategy and apply it consistently.

E.g., the second set of 3 strings that I dragged out to
mimic an "equivalent load" (as the first set that are
presently IN the tree) is only conceptually an identical
load. Making observations with one set in one case and
another set in another case isn't apples-apples.
Even though it might (and quite probably is!) appear to
be so.

For the purposes if this discussion, a hair dryer would do just fine.
If it trips, you know you have a problem in the wall or receptacle
string. Then try it at the end of the extension cord. If still no
trip, there is a problem with your lights.

You've not been paying attention to the numerous "experiments"
I've already conducted.

E.g., different extension cord -- trips. Different light strings (same
cord) -- trips. Different GFCI breaker (same branch circuit) same
extension cord, same lights -- trips. "Cold" lights -- trips.
"Warm" lights -- no trip.

Extension + cold lights plugged into non-GFCI branch circuit -- *no* trip.
Ditto for different GFCI branch circuit, no trip.

I.e., nothing wrong with extension cord *or* lights.

Toaster oven (reported by SWMBO) plugged into same outlet WITHOUT extension
cord -- trips.

Problem is *clearly* with the wiring in the wall -- the only thing common
to all fault cases and NOT present in any of the non-fault cases! And,
only manifests when a load is present. Furthermore, only when the load is
significant ("cold" lamp strings)

The idea that an incandescent light will trip a GFCI in normal
operation (no faults) is ludicrous.

The whole point of the discussion is that there *is* a fault!
Note that a much larger load (3X) had been present on the same branch
circuit last Winter with *no* problems for the entire season!

That tiny surge while the filament
is heating up is well inside the trip curve of any breaker I have ever
seen. It would certainly be less than the heat up time of a hair dryer
element.

Forecast was for a cold night, tonight. So, rushed to get *something*
working -- regardless of an "explanation" -- in the hour I had before
sunset.

As it was obvious that the problem had to be in the branch circuit,
I removed all receptacles, examined the routing of the conductors
within each Jbox, inspected all wire nuts, screw terminals, grounds,
etc. and, then, reassembled everything. Washed the "wet use" covers
just to make things look pretty (continuous sun exposure turns the
exterior paint to a powdery substance).

No "obvious" problems: no "bugs" falling out of the receptacles, no
corrosion on terminals, no exposed wires under wire nut skirts, no
nicks in insulation, no moisture in boxes, no mounting screws pressing
on conductors, no cables pinched in clamps, plenty of room in each box
(35 cu in), etc.

Circuit has been holding without any problem -- even in the (unexpected!)
rain that's been falling (and the "false alarm" for the cold weather!).
Added another 2 strands of lights (with a second extension cord) just
to push my luck...

Took the (inexpensive -- $1) precaution of fitting "child proof" plugs to
all unused outlets to ensure nothing *can* crawl into any of the outlets
in the future.

No way to ensure I can recreate the problem -- as I have no idea
what it *actually* was -- so I'll leave well enough alone and wait
for the next hiccup. Maybe buy some 20A receptacles to replace
these when I next have to go poking around in the Jboxes...

Case closed.

Perhaps something wasn't plugged all the way in and you fixed it when
you checked everything?

More likely that there was a neutral fault that was cleared when he
pulled everything apart and put it back.
Lots of mystery GFCI problems are fixed by an inspection that didn't
actually find a problem. Who knows what it was?
"It's all in the way you hold your mouth"

On Sat, 12 Dec 2015 13:40:02 -0500, wrote:

Lots of mystery GFCI problems are fixed by an inspection that didn't
actually find a problem. Who knows what it was?
"It's all in the way you hold your mouth"

A very unrecognized skill in this business ;-)