Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK. Same
effect. Reset the breaker, plugged the UPS back into the outlet that it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and see
if that solves the problem, but I'm not sure what kind of fault could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

AFCIs are rather new. Any installation that new should not have faked
grounds. Did you mean GFCIs?

Charles Schuler wrote:
AFCIs are rather new. Any installation that new should not have faked
grounds. Did you mean GFCIs?



No, I put the AFCI in myself after purchasing the house. However, a lot
of the wiring is late-40's vintage. That was a good enough reason in my
mind to think that an AFCI would be if anything more important here than
in new construction.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

On Feb 17, 6:42 pm, Nate Nagel wrote:
No, I put the AFCI in myself after purchasing the house. However, a lot
of the wiring is late-40's vintage. That was a good enough reason in my
mind to think that an AFCI would be if anything more important here than
in new construction.

First, break the problem into parts; then diagnose those parts. For
example, do you have other GFCIs in the bathroom or kitchen? If so,
then good. Run that computer extension cord to that GFCI; see
computer or extension cord causes the other GFCI to trip.

Have you run anything significant on that tripping AGFI circuit?
For example, if the AFGI circuit is somehow wired so that its neutral
(white) wire is started with another circuit, then AGFI trip will
occur. For example, an iron on that newly AGFIed circuit would be a
good test.

If any newly modified safety ground has somehow shorted to a neutral
wire, then that also will trip the AGFI. But long before taking
anything apart, first verify which suspect (computer and extension
cord, or AGFI circuit) causes GFCI trip.

Second, that plug-in protector is too far from earth AND is hoping
to earth via a wire bundled with other wires. Just two in a long list
of reasons why a power strip protector does not even claim (in
numerical specifications) protection from surges that would cause
damage. The length of that earthing wire (a short distance to earth
and a significantly long distance between computer and surge
protector) has long been necessary for effective protection. That
also means the 1940s mains box must be upgraded so that earthing both
meets and exceeds post 1990 National Electrical Code requirements.

w_tom wrote:


Second, that plug-in protector is too far from earth AND is hoping
to earth via a wire bundled with other wires. Just two in a long list
of reasons why a power strip protector does not even claim (in
numerical specifications) protection from surges that would cause
damage. The length of that earthing wire (a short distance to earth
and a significantly long distance between computer and surge
protector) has long been necessary for effective protection.


Complete bullcrap.

Manufacturer specs for protection are readily available for plug-in
suppressors.

Both the IEEE guide on surges and surge protection at:
http://www.mikeholt.com/files/PDF/Li...ion_May051.pdf
and the NIST guide at:
http://www.nist.gov/public_affairs/p.../surgesfnl.pdf
say that plug-in suppressors are effective.

Plug-in suppressors, as explained in the IEEE guide, work primarily by
clamping the voltage on all wires (power and signal) to the common
ground at the suppressor. They do not work primarily by earthing.

--
bud--

"Nate Nagel" wrote in message
...
Charles Schuler wrote:
AFCIs are rather new. Any installation that new should not have faked
grounds. Did you mean GFCIs?



No, I put the AFCI in myself after purchasing the house.

Unless the authorities "know" about what you are doing, I suggest you
replace the AFCI with either a normal breaker or jus a GFCI breaker.

The AFCI is quickly developing a reputation among the "pros" as something
that will cause the homeowner to make a lot of trips between the bedroom and
the basement.

If the NEC really, really considered arc faults to be a special danger in
bedrooms, it should have considered making arc detection set off an alarm
rather than cutting off the power.

This scheme (AFCI for bedroom circuits) is the equivalent of having a smoke
detector turn off the lights rather than just make a loud noise.

On Sun, 18 Feb 2007 22:41:04 -0500, "John Gilmer"
wrote:


"Nate Nagel" wrote in message
...
Charles Schuler wrote:
AFCIs are rather new. Any installation that new should not have faked
grounds. Did you mean GFCIs?



No, I put the AFCI in myself after purchasing the house.

Unless the authorities "know" about what you are doing, I suggest you
replace the AFCI with either a normal breaker or jus a GFCI breaker.

The AFCI is quickly developing a reputation among the "pros" as something
that will cause the homeowner to make a lot of trips between the bedroom and
the basement.

If the NEC really, really considered arc faults to be a special danger in
bedrooms, it should have considered making arc detection set off an alarm
rather than cutting off the power.

This scheme (AFCI for bedroom circuits) is the equivalent of having a smoke
detector turn off the lights rather than just make a loud noise.


you're supposed to light a candle :-)
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

This scheme (AFCI for bedroom circuits) is the equivalent of having a
smoke
detector turn off the lights rather than just make a loud noise.


you're supposed to light a candle :-)

I was a little too hard on the NEC. The AFCI will cut off a circuit well
before a loose connection gets hot enough to actually be a safety problem.

It does happen. I found a loose wire when I realized that a plug for a
lamp was WARM. Years ago the fire department responded to a small fire
from a "hot" outlet.

I hope that withing a few years the AFCI manufacturers/NEC will sort things
out. In the past the NEC as paid attention to the problems of false
tripping.

For the time being, I would suggest that folks don't volunteer to get them
installed.

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

"Nate Nagel" wrote in message
...
Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK. Same
effect. Reset the breaker, plugged the UPS back into the outlet that it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and see
if that solves the problem, but I'm not sure what kind of fault could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate


Is that circuit part of a three wire cable (Black, red, white) used for two
circuits or is it just a two wire bx with the armor as the grounding
conductor?

John Grabowski wrote:
"Nate Nagel" wrote in message
...

Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK. Same
effect. Reset the breaker, plugged the UPS back into the outlet that it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and see
if that solves the problem, but I'm not sure what kind of fault could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate



Is that circuit part of a three wire cable (Black, red, white) used for two
circuits or is it just a two wire bx with the armor as the grounding
conductor?


It's two conductor BX with the armor grounded.

nate


--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

"Nate Nagel" wrote in message
...
John Grabowski wrote:
"Nate Nagel" wrote in message
...

Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK. Same
effect. Reset the breaker, plugged the UPS back into the outlet that it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and see
if that solves the problem, but I'm not sure what kind of fault could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate



Is that circuit part of a three wire cable (Black, red, white) used for
two
circuits or is it just a two wire bx with the armor as the grounding
conductor?


It's two conductor BX with the armor grounded.



AFCI circuit breakers are not required here in New Jersey, so I don't have
much experience diagnosing problems with them. My thoughts are that your
AFCI does not like the BX armor ground, there is something else going on
with the BX cable, or it does not like your UPS. Have you tried plugging in
another three prong appliance into the outlet?

John Grabowski wrote:
"Nate Nagel" wrote in message
...

John Grabowski wrote:

"Nate Nagel" wrote in message
...


Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK. Same
effect. Reset the breaker, plugged the UPS back into the outlet that it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and see
if that solves the problem, but I'm not sure what kind of fault could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate



Is that circuit part of a three wire cable (Black, red, white) used for

two

circuits or is it just a two wire bx with the armor as the grounding
conductor?


It's two conductor BX with the armor grounded.




AFCI circuit breakers are not required here in New Jersey, so I don't have
much experience diagnosing problems with them. My thoughts are that your
AFCI does not like the BX armor ground, there is something else going on
with the BX cable, or it does not like your UPS. Have you tried plugging in
another three prong appliance into the outlet?


No, that outlet has been unused since we've moved in. It is however the
first one in the circuit so the only possibilities I can see are that
the AFCI is actually a GFCI as well (anyone know?) and there's enough
current flowing through the real ground due to the UPS's fault sensing
circuit, OR that there is a physical problem with that receptacle, which
I'll be attempting to rule out shortly, now that the sun is up. (I've
been on a program of replacing all the receptacles as soon as wiring
"issues" are cleared, because a lot of the old receptacles were loose as
well.)

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

AFCI's do have GFCI functionality, but they trip at 60 ma instead of the 5
ma of a GFCI



"Nate Nagel" wrote in message
...
John Grabowski wrote:
"Nate Nagel" wrote in message
...

John Grabowski wrote:

"Nate Nagel" wrote in message
...


Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I have
found a significant number of grounds "bootlegged." Little by little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is. So
as
a stopgap until I get around to fixing everything correctly I wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged the
extension cord into the correct outlet. Then I plugged the UPS into
the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK.
Same
effect. Reset the breaker, plugged the UPS back into the outlet that
it
was using before, and everything is fine. This is a less than year old
APC unit.

Is there some fundamental incompatibility between this UPS and the
AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard
that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out) and
see
if that solves the problem, but I'm not sure what kind of fault could
be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate



Is that circuit part of a three wire cable (Black, red, white) used for

two

circuits or is it just a two wire bx with the armor as the grounding
conductor?


It's two conductor BX with the armor grounded.




AFCI circuit breakers are not required here in New Jersey, so I don't
have
much experience diagnosing problems with them. My thoughts are that your
AFCI does not like the BX armor ground, there is something else going on
with the BX cable, or it does not like your UPS. Have you tried plugging
in
another three prong appliance into the outlet?


No, that outlet has been unused since we've moved in. It is however the
first one in the circuit so the only possibilities I can see are that the
AFCI is actually a GFCI as well (anyone know?) and there's enough current
flowing through the real ground due to the UPS's fault sensing circuit, OR
that there is a physical problem with that receptacle, which I'll be
attempting to rule out shortly, now that the sun is up. (I've been on a
program of replacing all the receptacles as soon as wiring "issues" are
cleared, because a lot of the old receptacles were loose as well.)

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Nate Nagel wrote:
John Grabowski wrote:

"Nate Nagel" wrote in message
...

John Grabowski wrote:

"Nate Nagel" wrote in message
...


Hi all,

got a weird issue. In an upstairs bedroom, I have a computer that is
running off a UPS. After investigating the wiring in the house, I
have
found a significant number of grounds "bootlegged." Little by
little I
am picking away at them, but until spring, the upstairs will remain as
is because it's darn cold in the attic at the moment.

So here's the deal. I have determined that there is one properly
grounded outlet in the room where the computer is, because that outlet
is fed directly from the breaker panel, and that homerun is in BX not
the cloth covered Romex that the rest of the concealed wiring is.
So as
a stopgap until I get around to fixing everything correctly I
wanted to
make sure that the computer's UPS was plugged into that particular
outlet for proper surge protection. I bought a heavy extension cord,
unplugged the UPS from the outlet that it was plugged into, plugged
the
extension cord into the correct outlet. Then I plugged the UPS
into the
extension cord, and the lights went out. Reset the breaker, figuring
that I just made an arc, if I plugged it in faster it would be OK.
Same
effect. Reset the breaker, plugged the UPS back into the outlet
that it
was using before, and everything is fine. This is a less than year
old
APC unit.

Is there some fundamental incompatibility between this UPS and the
AFCI?
I'm wondering if the UPS tests for the presence of an earth ground
(there is a "building wiring fault" light on it) and if so does that
cause enough current to trip the AFCI? (I wouldn't have found this
before, because the outlet into which it's currently plugged is not
grounded but has the ground bootlegged to the neutral.) I've heard
that
some AFCIs are also GFCIs is why I'm asking. The AFCI is a Siemens
Q115AF breaker in the breaker panel.

I'll replace the receptacle in the morning (once it's light out)
and see
if that solves the problem, but I'm not sure what kind of fault
could be
in a receptacle that would cause a breaker, AFCI or not, to trip only
when a load is connected to it but not when a plug is inserted.

Does this mean also that I run the risk of having the AFCI trip if the
surge protection of the UPS kicks in?

Should I just give up the idea of having everything "to code" and
ditch
the AFCI and/or investigate the possibility of running a dedicated
circuit to that bedroom to feed an outlet solely for the computer, not
protected by the AFCI?

any thoughts greatly appreciated...

nate




Is that circuit part of a three wire cable (Black, red, white) used for


two

circuits or is it just a two wire bx with the armor as the grounding
conductor?


It's two conductor BX with the armor grounded.




AFCI circuit breakers are not required here in New Jersey, so I don't
have
much experience diagnosing problems with them. My thoughts are that your
AFCI does not like the BX armor ground, there is something else going on
with the BX cable, or it does not like your UPS. Have you tried
plugging in
another three prong appliance into the outlet?


No, that outlet has been unused since we've moved in. It is however the
first one in the circuit so the only possibilities I can see are that
the AFCI is actually a GFCI as well (anyone know?) and there's enough
current flowing through the real ground due to the UPS's fault sensing
circuit, OR that there is a physical problem with that receptacle, which
I'll be attempting to rule out shortly, now that the sun is up. (I've
been on a program of replacing all the receptacles as soon as wiring
"issues" are cleared, because a lot of the old receptacles were loose as
well.)

nate


Update:

I replaced the receptacle. when I turned the breaker back on it tripped
immediately. I popped the cover on the panel and ohmed everything out,
seemed OK although the resistance hot to ground was lower than I thought
(~1 meg; nothing plugged in) although granted my meter is very old and
possibly inaccurate. Everything seemed OK so I tried pulling the wires
*leaving* the receptacle I'd just replaced. Then reset the breaker.
Fine. Plugged in UPS. Fine. Reattached wires and replaced breaker
with regular 15A breaker. Fine. Tried another AFCI breaker (I just so
happened to have one laying around because I wanted to split the
upstairs into two circuits eventually.) Tripped immediately. Removed
the wires leaving the receptacle again, new AFCI did not trip.

So what I apparently have is something is causing the AFCI to
electronically trip but not because of overcurrent. It's got to be a
wiring fault because I have everything unplugged. and all I know is
that it is somewhere upstairs - one circuit serves the whole second
floor, except for one outlet in the hallway (apparently intended for an
air conditioner.)

I'm not sure why it tripped only when I plugged the UPS in before,
coincidence, or just reached some kind of threshold? who knows?

F'ing great. Of course it's about 10 degrees outside, and I assume most
of this wiring is in the attic. I'm a little too paranoid to just leave
the regular 15A breaker in... or are the Siemens AFCI breakers known to
be problematic?

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel