ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Page 1 of 3 1 2 3 >
Topic Options
Rate This Topic
#50003 - 03/22/05 03:42 PM nongrounded circuit extension, GFI won't trip
bucketman Offline
Member
Registered: 10/31/04
Posts: 72
Loc: vancouver WA, USA.
I've got circuit thats not grounded.
h\o wanted it extended so I put my GFI in and externded it. At the end of the job I heat it up and test everything plugs and lights.
testing plugs via an ideal plug tester with GFI test button. So I notice two things when testing, I've got a High impedance ground and the GFI isn't tripping.

My question is why is the GFI not tripping?

I checked my tester, it works on others.
and I know why I have the high impedance.
GFIs test the imbalance between hot and neutral right?
Does my plug tester test to ground?
If my plug tester test to ground and sence I basicly don't have one that could make it not trip right?
Top
Work Gear for Electricians and the Trades
#50004 - 03/22/05 03:51 PM Re: nongrounded circuit extension, GFI won't trip
CTwireman Offline
Member
Registered: 02/07/02
Posts: 840
Loc: Connecticut, USA
Unfortunately, you can't extend an ungrounded circuit, so you have created a violation there.

For this circuit to be code compliant, you must run a separate EGC back to a code compliant location. After you run the EGC, the GFCI isn't necesary unless it's in a location that requires one.

The GFCI will still function without the EGC.

The plug-in testers shunt the leakage current to ground, and since you don't have one, that's why it won't trip with it.

Peter

[This message has been edited by CTwireman (edited 03-22-2005).]
_________________________
Peter
Top
#50005 - 03/22/05 04:32 PM Re: nongrounded circuit extension, GFI won't trip
hurk27 Offline
Member
Registered: 05/15/02
Posts: 68
Loc: Portage, Indiana
Quote:
Unfortunately, you can't extend an ungrounded circuit, so you have created a violation there.


This is news to me?
406.3(C) FPN clearly references 250.130 for doing just that. And 250.130 say's:

Quote:
For replacement of non–grounding-type receptacles with grounding-type receptacles and for branch-circuit extensions only in existing installations that do not have an equipment grounding conductor in the branch circuit, connections shall be permitted as indicated in 250.130(C).


As for the plug in tester yes it does use the grounding conductor to trip the GFCI but pay no attention to it as the button on the GFCI is the only UL listed way to test a GFCI or AFCI.

[This message has been edited by hurk27 (edited 03-22-2005).]
_________________________
Be Fair, Be Safe
Just don't be Fairly Safe
Top
#50006 - 03/22/05 04:49 PM Re: nongrounded circuit extension, GFI won't trip
hurk27 Offline
Member
Registered: 05/15/02
Posts: 68
Loc: Portage, Indiana
Whoop's I guess I should of read 250.130(C) instead of shooting from the hips....
_________________________
Be Fair, Be Safe
Just don't be Fairly Safe
Top
#50007 - 03/22/05 06:05 PM Re: nongrounded circuit extension, GFI won't trip
bucketman Offline
Member
Registered: 10/31/04
Posts: 72
Loc: vancouver WA, USA.
you hip shooters make me so emotional.

hurk27 thanks for the responce.
So how do we test on the load side of the GFI?
Is the load side really GFIed?
how would I make an inbalince safely?
Top
#50008 - 03/22/05 06:44 PM Re: nongrounded circuit extension, GFI won't trip
hypress Offline
Member
Registered: 07/20/04
Posts: 129
Loc: Charleston WV
I have run in to that problem before ( the GFCI trips when self tested but will not test with tester ). The GFCI is probaply OK but you need a reference ground for current flow. The solution is plug an extention cord into a known grounded outlet drag the other end to the new extended circuit take a wiggie and go between the hot side of the GFCI and the ground wire of the extention cord. the GFCI should trip instantaly.
Anouther idea would be plug in adapter 3wire to 2 wire on the extention cord plug the cord into the circuit that was extended AHEAD OF the GFCI ( ON THE LINE SIDE OF THE GFCI ) then take the wiggie and go between the hot side of the wiggie and the neutral side of the extention cord. the GFCI should trip instantly.
Top
#50009 - 03/23/05 03:35 AM Re: nongrounded circuit extension, GFI won't trip
Steve Miller Offline
Member
Registered: 08/30/01
Posts: 325
Loc: Loudoun Cty, VA
The way I read this section (250.130C)...
"The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:" ... it says the egc 'shall be permitted to be connected', not it 'shall be connected'. Therefore you could extend the ungrounded circuit with an ungrounded circuit. Not the best choice, but legal.
Top
#50010 - 03/23/05 03:51 AM Re: nongrounded circuit extension, GFI won't trip
safetygem Offline
Member
Registered: 01/30/02
Posts: 119
Loc: Ohio, USA
Hurk... another shot from the hip?
Quote:
the button on the GFCI is the only UL listed way to test a GFCI...


Information from UL
Quote:
Q: How does a regulatory authority test Ground Fault Circuit Interrupters (GFCIs) in the field?

A: A GFCI should always be tested using the "test" button on the GFCI. When verifying GFCI protection of circuits that are not within sight of the device (such as verifying GFCI-protected circuits fed downstream from a feed-through GFCI receptacle, or verifying that a receptacle outlet is protected by a remotely located GFCI circuit breaker), some individuals may choose to use external GFCI testers that will introduce a fault current sufficient to open a properly wired and protected circuit. The markings and instructions provided with the UL Listed GFCI tester should be followed in all cases.

A negative reading from the tester can occur for a variety of reasons, including improper wiring or a malfunctioning GFCI. When a negative reading from the tester is obtained, additional investigation of the circuit is needed to verify proper wiring and protection. GFCI testers may provide a negative result when the circuit does not have a proper ground path. A negative reading can also result when the GFCI being tested is not connected to a 120V supply source. As technology has advanced, GFCI manufacturers have worked to improve the operation of these devices through the use of sensing circuitry, which requires the AC source to be present in order for the device to sense a ground fault condition and open the circuit. Some older model GFCI testers may not include instructions that require the GFCI to be energized during the test. Simply imparting a fault current as with previous technology may not provide an accurate reading and could result in unnecessary time spent tracking down problems that don't exist. To avoid false readings, connect the GFCI to the 120V supply while it is being tested for proper operation.

For more information on GFCIs, contact Paul Orr in Melville, N.Y., by phone at +1-631-271-6200; or by e-mail at Paul.Orr@us.ul.com.


This comes from the Spring 04 edition of the UL publication "The Code Authority." http://www.ul.com/tca/summer04/qa.html

Also, frequently this problem can be related to a "defective" GFCI that is taking too long to trip. The "SureTest" ideal tester frequently will indicate the time lag exceeds 6 seconds, which would violate the listing. So, the test button may cause a trip, but, the actual trip time is too long.

Edited to add direct link to UL article.

[This message has been edited by safetygem (edited 03-23-2005).]
Top
#50011 - 03/23/05 07:12 AM Re: nongrounded circuit extension, GFI won't trip
CTwireman Offline
Member
Registered: 02/07/02
Posts: 840
Loc: Connecticut, USA
Quote:
The way I read this section (250.130C)...
"The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:" ... it says the egc 'shall be permitted to be connected', not it 'shall be connected'. Therefore you could extend the ungrounded circuit with an ungrounded circuit. Not the best choice, but legal.


I don't agree. Nowhere do I see permission to extend the circuit ungrounded.
_________________________
Peter
Top
#50012 - 03/23/05 07:19 AM Re: nongrounded circuit extension, GFI won't trip
CTwireman Offline
Member
Registered: 02/07/02
Posts: 840
Loc: Connecticut, USA
OK, here is something a little more solid.

If you did extend the circuit ungrounded, you couldn't install a 2-wire receptacle. Otherwise you would violate 406.3 (A). A new circuit must have grounded receptacle, it is not a "replacement" situation.

Bottom line: for a non-grounded BC extension, you must install a grounded-type receptacle, and the EGC must be connected per 250.130(C).
_________________________
Peter
Top
Page 1 of 3 1 2 3 >

Member Spotlight
Member Since: 08/22/05
Posts: 44
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 68 Guests and 9 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
Stack, Scotto, Freecrowder, clee512, Jdscott2005

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals