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 08-24-2012, 10:35 PM   #16
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 5,040
Rewards Points: 2,050
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.
It's called a bootleg ground. I thought of that today but was not able to get back till now. Absolutely do not connect neutral to ground with a jumper. Your neutral is a current carrying wire and part of the electrical circuit. If you jumper it you will energize the metal box and any appliances metal case plugged into that receptacle. When it becomes most dangerous is if your neutral would open. With that jumper to the neutral you have provided an alternate path to complete a circuit through ground. You never want to give neutral current access to anywhere other than where it is intended .... the white wire.

See if you can see the danger in the diagrams by installing a bootleg ground. The light blue dots are where neutral current will appear if you complete the circuit. Use of a bootleg let the current use the metal of the box and the appliance metal frame to seek a return to its source.

So heres the deal if you turn on the appliance it will not work because the neutral (grounded conductor) has opened some where downstream. When you touch the metal appliance it is possible for you to create the return path and neutral current because of that jumper has access to flow thru you via the connection you made to the neutral on the gfci. The good news is that it is a protected receptacle and should trip the minute it 'sees current' flowing where it shouldn't be.
Attached Thumbnails
2 Similar GFCI, but one tests open ground-120-volt-branch-circuit-bootleg.jpg   2 Similar GFCI, but one tests open ground-120-volt-branch-circuit-bootleg-1.jpg  


Last edited by Stubbie; 08-25-2012 at 01:06 AM.
Stubbie is offline   Reply With Quote
Old 08-25-2012, 02:27 PM   #17
Member
 
Join Date: Aug 2012
Posts: 471
Rewards Points: 300
Default

2 Similar GFCI, but one tests open ground


Does it make any difference that this circuit only goes to this one GFCI outlet and does not pass on to any other outlets or fixtures? While this is probably a violation of a code does it present a danger at the outlet? As you said the GFCI will trip.
crescere is offline   Reply With Quote
Old 08-25-2012, 03:13 PM   #18
A "Handy Husband"
 
rjniles's Avatar
 
Join Date: Feb 2007
Location: South Carolina Low Country
Posts: 4,107
Rewards Points: 2,124
Default

2 Similar GFCI, but one tests open ground


Besides being very dangerous and a code violation, if you bootleg the ground (to the neutral) it will trip the GFCI as soon as you plug something in and it will not reset.
__________________
Location:
Coastal South Carolina
rjniles is online now   Reply With Quote
Old 08-25-2012, 05:14 PM   #19
Member
 
Join Date: Aug 2012
Posts: 471
Rewards Points: 300
Default

2 Similar GFCI, but one tests open ground


RJ. I have tested and used this outlet with no problems. It responds to the test button and it operates appliances without tripping. I believe those who say it is not code, but what is the danger? What bad thing can happen? It seems fine so far.
crescere is offline   Reply With Quote
Old 08-25-2012, 06:35 PM   #20
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,131
Rewards Points: 2,054
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by rjniles View Post
Besides being very dangerous and a code violation, if you bootleg the ground (to the neutral) it will trip the GFCI as soon as you plug something in and it will not reset.
What makes you think this?
stickboy1375 is offline   Reply With Quote
Old 08-25-2012, 06:36 PM   #21
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,131
Rewards Points: 2,054
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by crescere View Post
RJ. I have tested and used this outlet with no problems. It responds to the test button and it operates appliances without tripping. I believe those who say it is not code, but what is the danger? What bad thing can happen? It seems fine so far.
It's a danger, remove the bootleg ground...
stickboy1375 is offline   Reply With Quote
Old 08-25-2012, 07:39 PM   #22
Member
 
Join Date: Aug 2012
Posts: 471
Rewards Points: 300
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by stickboy1375 View Post
It's a danger, remove the bootleg ground...
Thank you for the warning, but one of the reasons I am here is to learn how and why, not just what. As I have said the plug works and passes the test. Why is what this electrician told me to do dangerous? Thank you for any expanded explanations.
crescere is offline   Reply With Quote
Old 08-25-2012, 07:42 PM   #23
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by andrew79 View Post
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
already answered the safety aspect. Your basically turning all you metal parts into current carrying parts, make contact with any of them and you'll get a wake up call. Also your fault current is now going to run along your neutral possibly damaging appliances and electronics along the way
__________________
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.

Last edited by andrew79; 08-25-2012 at 07:45 PM.
andrew79 is offline   Reply With Quote
Old 08-25-2012, 08:21 PM   #24
Resi EC
 
Join Date: Aug 2012
Location: Kansas
Posts: 479
Rewards Points: 250
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by crescere View Post
Thank you for the warning, but one of the reasons I am here is to learn how and why, not just what. As I have said the plug works and passes the test. Why is what this electrician told me to do dangerous? Thank you for any expanded explanations.
Will try to explain this, if I miss something someone please correct me.

Lets say you leave the "bootleg" ground on, the microwave works great, now lets say, for some unseen reason you've lost the grounded conductor(neutral, white wire) in the wall, maybe a mouse chewed it up, doesn't matter, neutral is gone. With the "bootleg" ground now the hot feeding the microwave is looking for a return path to source (panel) with it being tied to the ground now the case of the microwave is hot, now the case is looking for a return path to source. Now Mrs. Renter is doing the dishes and as she turns the water off touches the microwave at the same time. One hand on the faucet, and one hand on the microwave .... big zap .... what between the two hands? Where will the current flow through, thats right Mrs. Renters heart, defibrillators don't start the heart they stop it
Gac66610 is offline   Reply With Quote
Old 08-25-2012, 08:25 PM   #25
Member
 
Join Date: Aug 2012
Posts: 471
Rewards Points: 300
Default

2 Similar GFCI, but one tests open ground


Maybe I am not explaining what I did correctly. The GFCI was testing as ungrounded. I attached a white wire from the silver side, ie Line neutral (NOT hot), to the green ground screw.

How can I make the box hot if the black wire attached to the brass line hot side is not involved? I have touched the box and I assure you it is not hot. I understand the current returns through the white neutral wire, but I have read that it is at 0 voltage. What am I not getting?
crescere is offline   Reply With Quote
Old 08-25-2012, 08:36 PM   #26
Member
 
Join Date: Aug 2012
Posts: 471
Rewards Points: 300
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by Gac66610 View Post
Will try to explain this, if I miss something someone please correct me.

Lets say you leave the "bootleg" ground on, the microwave works great, now lets say, for some unseen reason you've lost the grounded conductor(neutral, white wire) in the wall, maybe a mouse chewed it up, doesn't matter, neutral is gone. With the "bootleg" ground now the hot feeding the microwave is looking for a return path to source (panel) with it being tied to the ground now the case of the microwave is hot, now the case is looking for a return path to source. Now Mrs. Renter is doing the dishes and as she turns the water off touches the microwave at the same time. One hand on the faucet, and one hand on the microwave .... big zap .... what between the two hands? Where will the current flow through, thats right Mrs. Renters heart, defibrillators don't start the heart they stop it

Gac I posted my last before I saw your post. Thank you for that explanation. However, wouldn’t that happen even if I did not do the jumper? I have had white wires come off of outlets and the attached appliance did not become hot. The outlet simply did not work anymore.
crescere is offline   Reply With Quote
Old 08-25-2012, 08:56 PM   #27
Resi EC
 
Join Date: Aug 2012
Location: Kansas
Posts: 479
Rewards Points: 250
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by Gac66610 View Post
Will try to explain this, if I miss something someone please correct me.

Lets say you leave the "bootleg" ground on, the microwave works great, now lets say, for some unseen reason you've lost the grounded conductor(neutral, white wire) in the wall, maybe a mouse chewed it up, doesn't matter, neutral is gone. With the "bootleg" ground now the hot feeding the microwave is looking for a return path to source (panel) with it being tied to the ground now the case of the microwave is hot, now the case is looking for a return path to source. Now Mrs. Renter is doing the dishes and as she turns the water off touches the microwave at the same time. One hand on the faucet, and one hand on the microwave .... big zap .... what between the two hands? Where will the current flow through, thats right Mrs. Renters heart, defibrillators don't start the heart they stop it
So you know current travels back through the white, and you agree that the current flows through the appliance,(black to white) now the incidence happens (in red above) with the "bootleg" wire tied from the neutral to ground the ground is the neutral the ground is attached box the box is now the neutral, if its a three prong cord the ground prong is the neutral, and the ground on that cord is attached to the appliance housing, now the appliance housing is the neutral looking for a path back to source.
Gac66610 is offline   Reply With Quote
Old 08-25-2012, 09:01 PM   #28
Resi EC
 
Join Date: Aug 2012
Location: Kansas
Posts: 479
Rewards Points: 250
Default

2 Similar GFCI, but one tests open ground


Quote:
Originally Posted by crescere View Post
Gac I posted my last before I saw your post. Thank you for that explanation. However, wouldn’t that happen even if I did not do the jumper? I have had white wires come off of outlets and the attached appliance did not become hot. The outlet simply did not work anymore.
We are catching between posts

No where in the appliance is the neutral attached to the housing, atleast its not suppose to be, hence the GFCI protection will pick that up
Gac66610 is offline   Reply With Quote
Old 08-25-2012, 10:18 PM   #29
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 5,040
Rewards Points: 2,050
Default

2 Similar GFCI, but one tests open ground


Are you just wanting the receptacle tester to say things are correct even though you are fooling it into thinking there is a ground when there isn't ?


It is not correct and neutral current can electrocute you. I understand it is a difficult concept to understand but it has to do with alternating current and you providing a potential difference with the neutral wire or the metal connected to the neutral because of that bootleg jumper.

Last edited by Stubbie; 08-26-2012 at 02:09 AM.
Stubbie is offline   Reply With Quote
Old 08-25-2012, 10:44 PM   #30
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

2 Similar GFCI, but one tests open ground


a trade school teacher once explained it me like this. forgive the language.

**** in equals **** out.

so whatever you have going in on the black you have to have coming back on the white(if everythings working right). say you have a 5amp appliance running, your white now has 5amps on it.(forgetting mwbc for this argument).

a bootleg ground makes metal parts part of the "**** out" half of the circuit. a case grounded appliance plugged into this circuit could have the amperage running through it's outer case.

__________________
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.