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Home > Archive > Electrical Engineering > April 2006 > Hot ground wire?
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| Help! I have a problem with a circuit in my home. A home inspector
just finished and one of his serious concerns was a circuit that he
said had a ground problem. He was very concerned and said I should
address it immediately. He used a tester that had 3 prongs and a set
of lights for each. All 3 lights were on.
I checked it with 3 different tester I have and they also indicated
that the neutral and ground were hot.??? I called a local service
group and they sent an electrician. He had a similar tester to the
inspector's, it showed there was no problem. After he left I rechecked
and got mixed results. I ended up using an alligator clip and ran it
between the ground wire and the probe tip on a PAMA circuit tester.
The light would come on in varying intensitity and stay for varying
periods, then go out and return later.
I also noticed that a surge protector's ground light on another outlet
on the same circuit flickers. The evidenece tells my I have a problem,
but with conflicting opinions, I thought I'd check it out here. The
house is 18 years old and we haven't had any prior noticeable problems.
| |
| phil-news-nospam@ipal.net 2006-04-16, 3:21 am |
| On 15 Apr 2006 20:12:22 -0700 Tom <tom@bilt2last.us> wrote:
| Help! I have a problem with a circuit in my home. A home inspector
| just finished and one of his serious concerns was a circuit that he
| said had a ground problem. He was very concerned and said I should
| address it immediately. He used a tester that had 3 prongs and a set
| of lights for each. All 3 lights were on.
What kind of lights were these? Neon? Incandescent? Were the lights
at the same brightness?
| I checked it with 3 different tester I have and they also indicated
| that the neutral and ground were hot.??? I called a local service
| group and they sent an electrician. He had a similar tester to the
| inspector's, it showed there was no problem. After he left I rechecked
| and got mixed results. I ended up using an alligator clip and ran it
| between the ground wire and the probe tip on a PAMA circuit tester.
| The light would come on in varying intensitity and stay for varying
| periods, then go out and return later.
If both neutral and ground are hot, then you could not get the light that
connects between them to light, insless they are hot at different phases.
| I also noticed that a surge protector's ground light on another outlet
| on the same circuit flickers. The evidenece tells my I have a problem,
| but with conflicting opinions, I thought I'd check it out here. The
| house is 18 years old and we haven't had any prior noticeable problems.
I suspect this outlet is on a "shared neutral" circuit another outlet that
has something plugged in and turned on, with the neutral connection broken
somewhere upstream towards, or at, the source (the breaker panel). That
can make the neutral hot. But that is all that would be needed to light
up all three lights. The light between hot and neutral would see some
big fraction of the 240 volts. The other 2 lights go to ground and would
light up of ground is NOT hot.
Is there a "double" (or 2-pole) breaker feeding this circuit? What else
is on the circuit? I suggest you shut that circuit off at the breaker,
and then verify that the power is off with the tester. Then hire an
electrician to deal with the problem.
--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------
| |
| gfretwell@aol.com 2006-04-16, 11:21 am |
| On 15 Apr 2006 20:12:22 -0700, "Tom" <tom@bilt2last.us> wrote:
>Help! I have a problem with a circuit in my home. A home inspector
>just finished and one of his serious concerns was a circuit that he
>said had a ground problem. He was very concerned and said I should
>address it immediately. He used a tester that had 3 prongs and a set
>of lights for each. All 3 lights were on.
>
>I checked it with 3 different tester I have and they also indicated
>that the neutral and ground were hot.??? I called a local service
>group and they sent an electrician. He had a similar tester to the
>inspector's, it showed there was no problem. After he left I rechecked
>and got mixed results. I ended up using an alligator clip and ran it
>between the ground wire and the probe tip on a PAMA circuit tester.
>The light would come on in varying intensitity and stay for varying
>periods, then go out and return later.
>
>I also noticed that a surge protector's ground light on another outlet
>on the same circuit flickers. The evidenece tells my I have a problem,
>but with conflicting opinions, I thought I'd check it out here. The
>house is 18 years old and we haven't had any prior noticeable problems.
That sounds like a bad neutral connection. Are the receptacles
"backstabbed"?
| |
| Charles Perry 2006-04-16, 1:21 pm |
|
<gfretwell@aol.com> wrote in message
news:s2j4421ll8j8i1eivf6csbt761g3ogca2r@4ax.com...
> On 15 Apr 2006 20:12:22 -0700, "Tom" <tom@bilt2last.us> wrote:
<snip>
> That sounds like a bad neutral connection. Are the receptacles
> "backstabbed"?
"Backstabbed", I like that term to describe this "wiring practice" (I use
wiring practice very loosely in this case). When an electrician wires a
receptical in this fashion, they are stabbing the premise owner in the back.
Charles Perry P.E.
| |
| electrician@electrician2.com 2006-04-16, 3:21 pm |
| <<I checked it with 3 different tester I have and they also indicated
that the neutral and ground were hot.??? I called a local service
group and they sent an electrician. He had a similar tester to the
inspector's, it showed there was no problem. After he left I rechecked
and got mixed results. I ended up using an alligator clip and ran it
between the ground wire and the probe tip on a PAMA circuit tester.
The light would come on in varying intensitity and stay for varying
periods, then go out and return later. >>
Use an analog circuit tester or a wiggy that loads the circuit being
tested. Digital testers are too sensitive and will give you erroneous
readings when testing power circuits.
| |
|
|
"Tom" <tom@bilt2last.us> wrote in message
news:1145157142.135131.270570@i40g2000cwc.googlegroups.com...
> Help! I have a problem with a circuit in my home. A home inspector
> just finished and one of his serious concerns was a circuit that he
> said had a ground problem. He was very concerned and said I should
> address it immediately. He used a tester that had 3 prongs and a set
> of lights for each. All 3 lights were on.
>
> I checked it with 3 different tester I have and they also indicated
> that the neutral and ground were hot.??? I called a local service
> group and they sent an electrician. He had a similar tester to the
> inspector's, it showed there was no problem. After he left I rechecked
> and got mixed results. I ended up using an alligator clip and ran it
> between the ground wire and the probe tip on a PAMA circuit tester.
> The light would come on in varying intensitity and stay for varying
> periods, then go out and return later.
>
> I also noticed that a surge protector's ground light on another outlet
> on the same circuit flickers. The evidenece tells my I have a problem,
> but with conflicting opinions, I thought I'd check it out here. The
> house is 18 years old and we haven't had any prior noticeable problems.
I challenge your premise.
Just exactly was the procedure to find that the neutral and ground were hot?
Neutrals do carry current/ voltage depending on where they are in the
circuit. Hence the title "grounded conductor".
A I have an plug strip that has been flickering for more than 5 years. Not a
problem, I am to cheap to get a new one, because the neon bulb is
flickering.
I suggest you find some one that knows how to use a multimeter.
Anyone who relies on a $39 "tool" to troubleshoot electrical work is not an
electrician, in my book. I would be run off from my customers if I showed up
with one of those.
| |
| electrician@electrician2.com 2006-04-16, 3:21 pm |
| <<"Backstabbed", I like that term to describe this "wiring practice" (I
use
wiring practice very loosely in this case). When an electrician wires
a
receptical in this fashion, they are stabbing the premise owner in the
back.
Charles Perry P.E. >>
I agree, however unless the job specification specifically does not
allow the back stabbing connectors, contractors will go with the
minimum requirements and UL lists the back stabbing devices. I recall
writing up a school job because the receptacles were back stabbed. The
contactor immediately protested and said he was following the UL
listing instructions and he won. It is UL's fault that the back
stabbing connectors are used in the first place- they list them.
| |
| Salmon Egg 2006-04-16, 3:21 pm |
| On 4/15/06 8:12 PM, in article
1145157142.135131.270570@i40g2000cwc.googlegroups.com, "Tom"
<tom@bilt2last.us> wrote:
> Help! I have a problem with a circuit in my home. A home inspector
> just finished and one of his serious concerns was a circuit that he
> said had a ground problem. He was very concerned and said I should
> address it immediately. He used a tester that had 3 prongs and a set
> of lights for each. All 3 lights were on.
>
> I checked it with 3 different tester I have and they also indicated
> that the neutral and ground were hot.??? I called a local service
> group and they sent an electrician. He had a similar tester to the
> inspector's, it showed there was no problem. After he left I rechecked
> and got mixed results. I ended up using an alligator clip and ran it
> between the ground wire and the probe tip on a PAMA circuit tester.
> The light would come on in varying intensitity and stay for varying
> periods, then go out and return later.
>
> I also noticed that a surge protector's ground light on another outlet
> on the same circuit flickers. The evidenece tells my I have a problem,
> but with conflicting opinions, I thought I'd check it out here. The
> house is 18 years old and we haven't had any prior noticeable problems.
>
Having just had a loose neutral problem taken care of, I am sensitive to
this kind of a problem. My tester indicated that both the ground and the
neutral were correctly connected. However, it is not capable of telling the
quality of those connections.
Pay serious attention to what the inspector said. You do not want to have
this problem show up even occasionally. The electrician sent to you
obviously does not have sufficient knowledge and/or experience.
Although I am a licensed PE in EE, my expertise is not in house wiring. I
deferred to an experienced hands-on electrician. I had already pinned down
the problem as a bad neutral connection. I think that I could have found the
specific failure but it would have taken me at least ten times as long. Even
then, just making the repair would have been much more difficult for me than
it was for him, because he knew what to do while I would have had to
improvise.
Bill
-- Ferme le Bush
| |
|
| Tom wrote:
> Help! I have a problem with a circuit in my home. A home inspector
> just finished and one of his serious concerns was a circuit that he
> said had a ground problem. He was very concerned and said I should
> address it immediately. He used a tester that had 3 prongs and a set
> of lights for each. All 3 lights were on.
>
> I checked it with 3 different tester I have and they also indicated
> that the neutral and ground were hot.??? I called a local service
> group and they sent an electrician. He had a similar tester to the
> inspector's, it showed there was no problem. After he left I rechecked
> and got mixed results. I ended up using an alligator clip and ran it
> between the ground wire and the probe tip on a PAMA circuit tester.
> The light would come on in varying intensitity and stay for varying
> periods, then go out and return later.
>
> I also noticed that a surge protector's ground light on another outlet
> on the same circuit flickers. The evidenece tells my I have a problem,
> but with conflicting opinions, I thought I'd check it out here. The
> house is 18 years old and we haven't had any prior noticeable problems.
>
I've seen this, and it was due to the design of the
three lite tester. Damn thing was designed to blink
all three lights when things were good, while experience
with different testers insisted that three lights on was
bad. A different 3 lite tester showed that the circuit
was correctly wired (at least as far as the tester is
capable). Physical inspection bore that out. Reading
glasses and a close look at the new three lite tester
showed that all three lights are supposed to blink rapidly
when things are good.
Use a real test lamp - a 60 or 100 watt bulb. It should
light when connected hot to neutral or hot to ground,
and should not light when connected ground to neutral.
Ed
| |
| Beachcomber 2006-04-17, 7:21 am |
|
>Use a real test lamp - a 60 or 100 watt bulb. It should
>light when connected hot to neutral or hot to ground,
>and should not light when connected ground to neutral.
>
>Ed
With one caveat... No 100 watt lamp is going to light up with a
difference of 20 volts or so between ground and neutral. If you have
a difference of this much voltage, you still have serious troubles.
Best to (also) measure the voltage between the three conductors with a
meter of known accuracy.
Beachcomber
| |
|
| electrician@electrician2.com wrote:
Nice!
[color=darkred]
> I agree, however unless the job specification specifically does not
> allow the back stabbing connectors, contractors will go with the
> minimum requirements and UL lists the back stabbing devices. I recall
> writing up a school job because the receptacles were back stabbed. The
> contactor immediately protested and said he was following the UL
> listing instructions and he won. It is UL's fault that the back
> stabbing connectors are used in the first place- they list them.
>
Everybody deplores backstabing. I've never seen anyone that defends it.
Does anyone have a clue why the UL standard includes backstabs?
bud--
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