Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-23-2012, 10:07 PM   #1
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


I have a new/old house that has mostly cables with only two wires; one black, one white, no ground wire. In the kitchen there are two GFCI outlets that are each on their own circuit. The GFCI on the left of the sink has the two wire cable coming in and it is attached to the “line” side. There are two wires going out from the” load” side that feed a regular outlet on the other side of the kitchen. The only ground is a cooper wire screwed to the metal box and attached to the GFCI green ground screw. This outlet functions fine and when I test it with my Gardner Bender GFCI outlet tester it registers as “correct.”
The GFCI on the right side of the sink is another situation. This outlet also has two wires correctly feeding into the line part of the GFCI and has a ground wire attached from the box just like the other GFCI. This GFCI does not have any wires going out from the load side. However this outlet tests as “open ground” on my GFCI tester. In fact when I press the button on top of the tester to test the outlet this outlet will not even shut off.

I don’t get it. Both of these outlets are almost identical except that the one on the left has lines going out to another outlet. Other than that they are both grounded to their boxes, and both have only a two wire cable coming in. Why does one test correct while the other says there is open ground? I have tried two different GFCI outlets in case the outlets were bad. Nothing changes. Please help as I am out of ideas.

crescere is offline   Reply With Quote
Old 08-23-2012, 10:12 PM   #2
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 7,697
Rewards Points: 2,192
Default

2 Similar GFCI, but one tests open ground


The ground wire might be disconnected before it get to the box with the GFI.

The 3 light plug-in tester will not trip an ungrounded 2 wire GFI.

__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is online now   Reply With Quote
Old 08-24-2012, 12:30 AM   #3
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


Jim, the only ground wire is the one attached from the metal box to the green screw on the GFCI. This is the case with both GFCIs. It is just the one that registers open ground.
crescere is offline   Reply With Quote
Old 08-24-2012, 08:10 AM   #4
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


I have probably presented this in a confusing way. I guess the overall question is how do I make a GFCI supplied with cable that only has black and white wires, and is only grounded to the box test “correct” on my plug in tester. Or why wouldn’t it test correct?
crescere is offline   Reply With Quote
Old 08-24-2012, 08:21 AM   #5
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

2 Similar GFCI, but one tests open ground


It was already answered. Just because its tied to the box with a wire doesn't mean its grounded. Most old homes don't have a ground wire. It just so happens that receptacle 1 has found a path home to ground and receptacle 2 does not. Only remedy for this situation is to replace the feed wire back to the panel with a new wire that contains a ground.

Homes with no ground require either a two prong outlet or a gfci plug marked no ground. So other than the no ground sticker it appears your good to go.
__________________
Sarcasm is my friend
I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.
andrew79 is offline   Reply With Quote
Old 08-24-2012, 08:56 AM   #6
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


Andrew, thanks for your answer. How did the outlet on the left find its way to ground? Is this common? Having one GFCI grounded and the other one stickered not grounded is going to look odd. Is it common to do that?
crescere is offline   Reply With Quote
Old 08-24-2012, 09:20 AM   #7
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 5,042
Rewards Points: 2,054
Default

2 Similar GFCI, but one tests open ground


Quote:
How did the outlet on the left find its way to ground?
Good question, you said it is powered by only two wires no ground, are those two wires in a metal conduit or are they in a cable like romex (ie nm cable) ? Only way it can be grounded is armored cable or metal conduit or someone ran a single ground wire to a proper grounding point. If you push the test button on the gfci will it trip ?

Quote:
Is this common?
In older homes lots of things are common. A gfci does not need a grounded circuit to work and protect you from electrocution.


Quote:
Having one GFCI grounded and the other one stickered not grounded is going to look odd. Is it common to do that?
Sure many older homes that have been upgraded with additions or wiring upgrades have a mixture of grounded and ungrounded wiring. Again a gfci doesn't care ... it offers the same protection with or without a ground wire.
Stubbie is online now   Reply With Quote
Old 08-24-2012, 10:34 AM   #8
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by stubie View Post
Good question, you said it is powered by only two wires no ground, are those two wires in a metal conduit or are they in a cable like romex (ie nm cable) ? Only way it can be grounded is armored cable or metal conduit or someone ran a single ground wire to a proper grounding point. If you push the test button on the gfci will it trip ?

Thank you for your help. This is a very frustrating problem, and I would like to understand it.

This is just old black colored cable that runs from the circuit board to the GFCI and then to another outlet on the other side of the kitchen. As far as I can tell that is ALL this circuit does. There is no conduit. It just runs through the wall and ceiling as old black cable containing one black wire and one white wire.

I do not understand why this GFCI outlet tests correctly, but the other one does not. Yes, when I push the test button both GFCIs will go off. The ONLY difference is that the one on the right does not test correct per my plug in tester. Both boxes are metal and both are only grounded to the box.
crescere is offline   Reply With Quote
Old 08-24-2012, 11:12 AM   #9
A "Handy Husband"
 
rjniles's Avatar
 
Join Date: Feb 2007
Location: South Carolina Low Country
Posts: 4,115
Rewards Points: 2,140
Default

2 Similar GFCI, but one tests open ground


Using a meter (not a non contact tester), test (with power on) from the hot side of the receptacle to the metal box. If you get about 120 volts, the box is grounded. It may not be a compliant ground.
__________________
Location:
Coastal South Carolina
rjniles is online now   Reply With Quote
Old 08-24-2012, 11:38 AM   #10
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


RJ thanks for your help. So I put one lead on the black wire and the other on the box itself? I have a meter, but I am not real familiar with it yet. I want to learn about this.
crescere is offline   Reply With Quote
Old 08-24-2012, 11:50 AM   #11
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,860
Rewards Points: 2,116
Default

2 Similar GFCI, but one tests open ground


A plug in gfci tester will only work with a grounded circuit.
The only true test of a gfci is the push to test button on the gfci.
What type of cable feeds the boxes these receptacles are in.
Without a ground wire in the cable, or the correct type of cable, you will read an open ground.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is online now   Reply With Quote
Old 08-24-2012, 08:59 PM   #12
Member
 
Join Date: Aug 2012
Posts: 472
Rewards Points: 302
Default

2 Similar GFCI, but one tests open ground


Well I have been advised by a seasoned electrician that I can merely put a jump wire between the white/neutral wire and the ground screw, snd sure enough that does make the GFCI "pass" the ground test according to the plug in tester.

I can't think of any danger involved in that.
crescere is offline   Reply With Quote
Old 08-24-2012, 09:29 PM   #13
Sparky
 
Join Date: Mar 2011
Location: Central Florida
Posts: 701
Rewards Points: 500
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by crescere View Post
Well I have been advised by a seasoned electrician that I can merely put a jump wire between the white/neutral wire and the ground screw, snd sure enough that does make the GFCI "pass" the ground test according to the plug in tester.

I can't think of any danger involved in that.


...
Techy is offline   Reply With Quote
Old 08-24-2012, 09:31 PM   #14
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,132
Rewards Points: 2,056
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by crescere View Post
Well I have been advised by a seasoned electrician that I can merely put a jump wire between the white/neutral wire and the ground screw, snd sure enough that does make the GFCI "pass" the ground test according to the plug in tester.

I can't think of any danger involved in that.
WOW... yeah, that is not allowed. and no electrician would ever give out that advice.
stickboy1375 is offline   Reply With Quote
Old 08-24-2012, 09:54 PM   #15
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

2 Similar GFCI, but one tests open ground


Your electricians a moron. Other than the fact your fault current now uses your neutral and any metal part is now part of the neutral circuit its totally safe

__________________
Sarcasm is my friend
I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.
andrew79 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding GFCI Breaker to Ground Outlets?? joerunner2 Electrical 9 11-12-2011 12:16 PM
Fried electronics after earth ground accidentally disconnected oukachiru Electrical 7 07-12-2011 03:05 PM
Open Ground in Non Daisy Chained Outlet Circuit RileyRR Electrical 2 05-18-2011 02:00 PM
240 volt load/appliance and ground vs neutral kgize Electrical 7 04-22-2010 11:40 PM
GFCI with no ground wire? gante Electrical 6 03-13-2009 09:17 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.