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Why does it read "open-ground?"


randynavarro
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Originally posted by randynavarro

Using a three-light tester, why would I get an "open-ground" reading when in fact I can see the ground wire connected to the receptacle?

What is the other end of that wire connected to in the box? Could be a nail through it somewhere or it could be clipped instead of connected at a splice someplace. Or as Phillip said may not be connected in the panel.

Occasionally I get an open ground reading because the fit in the receptacle is very loose and if you push the tester plug to one side you get contact. The ground it there, the receptacle should be replaced.

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What is the other end of that wire connected to in the box?
All the equipment grounds are connected in the panel.
Occasionally I get an open ground reading because the fit in the receptacle is very loose and if you push the tester plug to one side you get contact. The ground it there, the receptacle should be replaced.

I've jiggled much. Some outlets have been replaced with Decora style rec.. Those read open-ground as well.

BTW, I'm still here at the house. Y'all are experiencing Randy live on the site!

I've got another 30-40 minutes or so. I'll probably just tell 'em to have sparky figure it out. There's alum. branch circuits anyway-- a bigger problem to deal with.

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Randy,

Once you had the cover plate off it would have been very easy to check the ground with a multi-meter or a wiggy. One probe in the hot hole (technical term) and the other on the grounding screw (as you said the grounding wire was attached). If it indicated line voltage, then that would lead me to suspect worn out contacts at the receptacle itself. No voltage would be a loose connection in the grounding wiring somewhere "upstream".

If you use a multi-meter and had another nearby receptacle within reach of your leads that tested OK, you could also check continuity between the grounds...but the first test should tell you all you need to report.

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Originally posted by AHI

Originally posted by hausdok

Hmm,

I wonder if they have those thingys for T-Mobile?

OT - OF!!!

M.

Depending on what type of phone you have you can connect to the net via your existing cell phone.

http://www.tmobile.com/shop/addons/serv ... ataEmlSvcs

Nah,

Not me. It's hard enough reading something on a laptop screen, I sure as hell ain't gonna try reading an internet screen that's 2 inches by 1-1/2 inches. That card thingy sounds interesting though....

OT - OF!!!

M.

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Originally posted by randynavarro

Using a three-light tester, why would I get an "open-ground" reading when in fact I can see the ground wire connected to the receptacle?

There's no way to know. Whenever you get an anomolous reading with a three-light tester, pull out a multi-meter to confirm.

- Jim Katen, Oregon

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Originally posted by Jim Katen

There's no way to know. Whenever you get an anomolous reading with a three-light tester, pull out a multi-meter to confirm.

I might change that "whenever" to "most times". Had a 1920's beauty the other day. Updated in the 60's with a nice Zinsco panel, completely inaccessible behind an entertainment center. Still lots of KT (much buried) but all of the new wiring, attic and crawl, was as in the photos. There are some times you can trust the tester. [:-crazy]

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Mike,

I haven't checked but I'm almost positive all cellular providers carry the card. It fits in to the PCMCIA slot on the laptop. Most laptops have that slot; there's a few that don't.

IMO, its the only way to go. Especially in our area, most everyone is getting savvy about securing their wi-fi networks. I can rarely get on one from any particular location.

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If you use a multi-meter and had another nearby receptacle within reach of your leads that tested OK, you could also check continuity between the grounds...but the first test should tell you all you need to report.

Richard,

Using the multi-meter makes sense; however, isn't the reality that the three-light tester is actually fairly reliable after all? It basically found something that wasn't right. Pulling multiple cover plates and testing with a multi-meter seems beyond the normal scope (at least my normal scope.)

There's no way to know. Whenever you get an anomolous reading with a three-light tester, pull out a multi-meter to confirm.

Jim, I guess its the same question for you: is it important to know exactly what the problem is. Whenever you get a open-ground read on a three-light, has it ever been wrong?

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Originally posted by randynavarro

Whenever you get a open-ground read on a three-light, has it ever been wrong?

Well, I've had a 3-light tester tell me there were grounds when there weren't, so I suppose it could work the other way around.

I once did a house for an electrician. My SureTest said that there were about 11 open grounds on the first floor. The client said, "Haven't you got a real outlet tested?" I said, "What do you mean, one of those little 3 light testers?" He nodded, so I dug my 3-light out. He went back through and tested again and the 3-light tester said they were all grounded. I handed him a screwdriver and told him to open them up. He did - all of the EGC's had been nipped off. "Whoo-ee, I've got to get me one of those things," he said. I threw the 3-light tester away.

ONE TEAM - ONE FIGHT!!!

Mike

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Originally posted by randynavarro

. . . . Using the multi-meter makes sense; however, isn't the reality that the three-light tester is actually fairly reliable after all? It basically found something that wasn't right. Pulling multiple cover plates and testing with a multi-meter seems beyond the normal scope (at least my normal scope.)

It's fairly reliable at finding problems, but it's lousy at telling you what the problem is. Mulitple problems fool it. You don't need to pull the coverplate to use the multi-meter. If you just use the multi-meter leads and the slots in the receptacle faces, you can learn way more than you can with the three-light tester.

There's no way to know. Whenever you get an anomolous reading with a three-light tester, pull out a multi-meter to confirm.
Jim, I guess its the same question for you: is it important to know exactly what the problem is. Whenever you get a open-ground read on a three-light, has it ever been wrong?

It's important to narrow it down when the readings are anomolous. That is, not expected. If I'm inspecting a 1956 house with three-slot receptacles, I expect to find open grounds everywhere. There's no need to break out the multi-meter. On the other hand, if I'm inspecting a 2008 house and the three-light tester shows an open ground on one receptacle, I'm going to use the multi-meter to figure out what's going on.

The three-light tester has lied to me on occasion, mostly when there have been multiple problems.

- Jim Katen, Oregon

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I am under the impression the a three light will not detect a false ground. But then again, a Suretest may give a bad reading when used too close to the main panel.

As far as the all of the Decoras testing no ground, I think that may be a different cause than the regular duplex (may be). Are the receptacle boxes plastic or metal? Are the grounds attached?

I've seen some receptacles... like clock outlets, that MUST be wired to ground and not simply screwed in... even to a metal box.

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Originally posted by hausdok

Originally posted by AHI

Originally posted by hausdok

Hmm,

I wonder if they have those thingys for T-Mobile?

OT - OF!!!

M.

Depending on what type of phone you have you can connect to the net via your existing cell phone.

http://www.tmobile.com/shop/addons/serv ... ataEmlSvcs

Nah,

Not me. It's hard enough reading something on a laptop screen, I sure as hell ain't gonna try reading an internet screen that's 2 inches by 1-1/2 inches. That card thingy sounds interesting though....

OT - OF!!!

M.

No, what I mean is you use your cell phone as a wireless modem for your laptop. There is a cord that connects your phone to your laptop. The phone then becomes the connection link to the internet. Of course the wireless card for the laptop is another option.

I totally agree about not wanting to surf the net on a tiny screen.

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  • 2 weeks later...
Originally posted by AHI

Originally posted by hausdok

Originally posted by AHI

Originally posted by hausdok

Hmm,

I wonder if they have those thingys for T-Mobile?

OT - OF!!!

M.

Depending on what type of phone you have you can connect to the net via your existing cell phone.

http://www.tmobile.com/shop/addons/serv ... ataEmlSvcs

Nah,

Not me. It's hard enough reading something on a laptop screen, I sure as hell ain't gonna try reading an internet screen that's 2 inches by 1-1/2 inches. That card thingy sounds interesting though....

OT - OF!!!

M.

No, what I mean is you use your cell phone as a wireless modem for your laptop. There is a cord that connects your phone to your laptop. The phone then becomes the connection link to the internet. Of course the wireless card for the laptop is another option.

I totally agree about not wanting to surf the net on a tiny screen.

Can you take a call whil on the net?

I use a sprint card but am changing carriers in the summer.

As far as the three light tester-- I leave it slightly pulled back from the cover plate. The prongs of the device make a reliable point to touch the leads of the multi-meter.

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Originally posted by randynavarro

n you take a call whileon the net?

It's not attached to your cell phone at all.

It has its own cell phone number.

Randy,

I was asking about using a cell phone as a modem. I currently use a sprint card (with it's own number and bill).

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