open ground/ grounded outlets

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Old 01-14-07, 06:00 PM
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open ground/ grounded outlets

I went to go get new outlets for some of the rooms in my home, when I took out the old ones I noticed that they do not have the ground wires there. I think I heard that you are not suppoised to use grounded outlets with ungrounded units. I also thought I heard that to rectify this problem I could use gfi units, But if I don't have the ground wire how does this help?? Can someone help out THanx p.s I have alot of grounded outlets in the house and when I test them with the receptacle tester it shows open ground
 
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Old 01-14-07, 07:28 PM
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If no ground wire exists and someone installed grounded outlets they provided an unsafe condition. It is good that you discovered this. You are correct the use of gfci receptacles is one way to use grounded type receptacles when no ground exists. A gfci doesn't needed the ground wire to provide the protection for which it is designed.
If you have metal conduit such as emt instead of nm-b (romex) this may be your ground if no bare equipment ground wires exist so you may want to check. However, if you did not have any pigtails connected to the green screws of any of the receptacles then I would suspect you do not have a safety equipment ground in your wiring. You can test for this if you want by testing the hot side of a receptacle to the metal box with a simple two wire "neon" tester.
Anyway if you install a gfci first in the circuit then you may wire normal grounded outlets off the load side connections of that gfci. This will allow the single gfci to protect everything downstream of the gfci. A new gfci will come with little stickers that say "gfci protected...no equipment ground". Place these on the trim cover plates of all outlets.

Or you can install a gfci circuit breaker.

Or you can run an equipment ground wire from the panel to all receptacles you wish to use as ground type receptacles. However you might as well run new wiring rather than do this single wire deal.

Or you can install two prong ungrounded receptacles (least desirable choice).

A tester that shows open ground when one doest exist is normal. The condition though must be properly corrected.

If you have any grounding type receptacles that are showing ground and no ground exists let us know this is another dangerous situation.

Roger
 
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Old 01-14-07, 07:33 PM
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You are correct. You are not supposed to use 3 prong receps without a ground conductor. It gives the impression the outlet does have a ground.

If I read your post correctly, you do not even have a ground conductor in the box. Correct? What type of wiring feeds the boxes?


A gfci does not need a ground to be effective for its' purpose and design. It basically compares the current on the hot lead with the current with the neutral lead and if they are not within a specified closeness, it will trip.

The purpose and reasoning behid it is that if you have current flowing on the hot lead and not on the neutral, there is a problem since the current is flowing somewhere but not where it is intended to.

Any recep that is protected by a GFCI needs to be labeled as such. The labels are included with the recep generally.
 
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Old 01-14-07, 08:19 PM
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the wiring that feeds it is covered in a clothlike material. and the mounting boxes are metal. I replaced one of the recepticles with the three prong earlier tonight and when I checked it with the receptacle tester it showed that it was corect with the 2 amber lights, BUT I do not have a ground hooked up. Could it be hitting on the metal box and showing that it,s grounded??[I] just took the cover off and loostned the mounting bolts and as I loosten it the open groun light comes on, and as I tighten it the receptacle shows that its correct. Could my box be grounded if so how do I check that
 

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Old 01-14-07, 08:30 PM
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Look closely to see if there is a ground conductor within the cable. You have an older style romex (NM). the ground may simply be bent back so it is under ther connector which would provide some sort of ground. It is not legal to do it in this manner and I doubt it ever was but that doesn't mean it wasn't done.

Properly, the ground conductor (EGC) should enter the box and be attached to the metal box. It is a code requiremrnt the box be grounded.

Concerning the new receptacles.If the device is "self grounding" it would not legally require a pigtail to attch it to the box but I still prefer one. If it is not self grounding, it definately requires an EGC connected from the device to the box.
 
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Old 01-14-07, 08:31 PM
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Old cloth covered wire is old style NM cable. In the early years, this cable existed without a ground wire, which is the flavor that was used for most circuits in a house.

While it is true that in the US you can use a GFCI breaker or a properly placed GFCI receptacle and then use grounded receptacles on the circuit, this will not provide a ground. It will only provide a level protection somewhere between no ground and a properly grounded circuit.

The best option without running new circuits is to rewire with grounded cable, or to install ground wires.

My advice, instead, is to add new receptacles where you need new ones. With old wiring the number of receptacles and the number per circuit is likely to be less than ideal anyway, so you probably need new circuits. Then, to make the original circuits safe and proper, install ungrounded receptacles on these circuits.
 
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Old 01-14-07, 08:54 PM
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Look closely to see if there is a ground conductor within the cable O>K how do I do this what exactly am I looking for??
 
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Old 01-15-07, 08:19 AM
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I think they are simply asking you to look where the wiring enters the box and double check that there wasn't a bare wire screwed down inside the box somewhere. If there is you might be able to pigtail a ground to it and the box.
Based on what you are describing, it doesn't sound likely.

If not, I suppose you are getting a ground from the box through conduit. Is there conduit feeding the boxes? The new receptacle you are mounting sounds like it is self grounding to the metal box for you to get the tester results you are getting.
I'm curiuos---Can you see if you have continuity between the white wire entering the box and the box itself?

The other posts pretty much explain your options though...
 
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Old 01-15-07, 06:44 PM
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I presumed since he has old romex he doesn't have conduit or I figured he would have mentioned it.

If the tester shows a ground, the box must be grounded somehow. As I posted before, either a ground wire in the romex or a conduit would do it. What I was thinking was that the ground wire (if there is one, and you apparently don't see it in the box) that instead of attaching it in the box as required, the installer simply bent it back on itself so the romex connector would pinch it and provide some level of ground.

as far as self grounding, just about any recep will provide a ground but unless it is listed as "self grounding" it still requires a ground pigtail to it. They are manufactured slightly different than a non self grounding recep.
 
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Old 01-15-07, 07:30 PM
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O.K just to recap a bit.. My computer that I'm using right now is hooked up to a three prong receptacle,BUT it shows open ground so I'm assuming that it does not have a ground. Now if I switch this with a GFI receptacle Will this make it safe to use? I understand it is not the right way but I can't afford to rewire everything
 
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Old 01-15-07, 10:42 PM
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It is safe to use but it does not give you ground. It does give you a bit more safety than an ungrounded receptacle. Computers should be on a circuit that provides ground reference. Since we are having difficulty determining whether you actually have ground one sure way to tell is to remove the cover of your electrical panel (carefully) and tell us if any bare ground wires are terminated to the neutral bar. The fact that you have cloth wrapped wires tells me you dont have conduit but it is possible that the ground wire is there as NAP suggested earlier. You are getting so many conflicting results with that tester I would be happier if you would or have someone check the panel for equipment ground wires. Then get a two wire tester...some call them neon testers and check the hot side of a receptacle to the metal box and see if you have voltage. This will tell the story. Even so as NAP said your ground, if it is there and is bent over under the cable clamp is not very reliable and would need correction.

Roger

Roger
 
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