I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?

In my experience, the lights on the UPCs are about as useul as the "check
engine" light or "service engine now" light in cars. enough to tell you to
look at it, but not enough to tell ou what is wrong. And no 'codes" to pull
to help diagnosis.

I think there are only two things that can be wrong. First and most
commonis reversed polarity at the socket. Neutral on hot side and hot on
neutral side. Or in simpler terms white wire on dark brass screw, black
wire on bright silver screw. Note that the mix up ca be in a different
outlet box than the one where you are connecting the UPS. It could be
futher up the daisy chain.

The other error that the UPC could be picking up is an open ground.

I'm not going to give instructiomns on line because I don't want any
liability if you do it wrong. If you do already knw your way arund AC
branch circuits, both are easy but sometimes tedious tests with a quality
digital multmeter and a pair of Mark I eyeballs, and are eually easy but
sometimes tedious repairs.

--
Jim McLaughlin

Reply address is deliberately munged.
If you really need to reply directly, try:
jimdotmclaughlinatcomcastdotcom

And you know it is a dotnet not a dotcom
address.
"Bob" wrote in message
. ..
I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or
is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?

Jim McLaughlin wrote:

In my experience, the lights on the UPCs are about as useul as the "check
engine" light or "service engine now" light in cars. enough to tell you to
look at it, but not enough to tell ou what is wrong. And no 'codes" to pull
to help diagnosis.

I think there are only two things that can be wrong. First and most
commonis reversed polarity at the socket. Neutral on hot side and hot on
neutral side. Or in simpler terms white wire on dark brass screw, black
wire on bright silver screw. Note that the mix up ca be in a different
outlet box than the one where you are connecting the UPS. It could be
futher up the daisy chain.

The other error that the UPC could be picking up is an open ground.

I'm not going to give instructiomns on line because I don't want any
liability if you do it wrong. If you do already knw your way arund AC
branch circuits, both are easy but sometimes tedious tests with a quality
digital multmeter and a pair of Mark I eyeballs, and are eually easy but
sometimes tedious repairs.


I agree with everything you say, Jim. Except:

Why advise his using a "digital" multimeter rather than a good old
fashioned analog one?

Haven't we had enough questions here about "phantom" voltage readings
confusing non-technical folks? Those misleading readings occur because
of the extremely high input impedance of digital multimeters responding
to minute AC currents coupled by interwire capacitances. G

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"Rudeness is the weak man's imitation of strength."

Bob wrote:

I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?

One of the $10 ($15 with GFCI tester) little plug in three light testers
you can get most anywhere will identify most common wiring problems just
fine. Once you identify the problem either tackle it referencing a DIY
home wiring book from the library or have an electrician fix it for you
depending on your confidence / skill level.

Pete C.

Bud-- wrote:

Pete C. wrote:

Bob wrote:

I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?


One of the $10 ($15 with GFCI tester) little plug in three light testers
you can get most anywhere will identify most common wiring problems just
fine. Once you identify the problem either tackle it referencing a DIY
home wiring book from the library or have an electrician fix it for you
depending on your confidence / skill level.

Pete C.

Plug in testers can indicate a bad outlet but won't necessarily indicate
a good outlet. They run on very low current and, in particular, can't
give a reliable test of the ground wire. I would be more extreme than
Jeff and use a lightbulb in a pigtail socket.

bud--

It the fault was detected / reported by the APC UPS then the little
tester should readily identify it. The UPS isn't generally the most
sophisticated electrical tester.

Pete C.

Bob wrote:

I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?


You could try reading the manual ...

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

I have this same problem. Just bought a house that was built in the
early 50s. Put all of the computer equipment in the only bedroom that
had 3-pronged outlets and my UPS wiring fault lite came on. Killed the
CB and unscrewed the plug-in and sure enough, the prior owner replaced
the the old socket with a new one but did not add a ground wire. Now I
am getting ready to replace all of the wiring with new 12-2 w/g wire.

Bob wrote:
I plugged a APC UPS system in to a socket in my house and a red light came
on that is labeled "wiring fault." Does this mean there is no ground or is
it detecting some other problem? Is there a way to trouble shoot and find
what the fault is?