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#180878 - 09/14/08 07:53 PM 2 GFCIs on same circuit
SheBeInspector Offline
New Member

Registered: 04/23/07
Posts: 3
Loc: California
Greetings to all: A 2.5-hour search in various Forums was futile, so here's my question:
A random poll of certified home inspectors at a state association-sponsored electrical seminar revealed that many of us find "dueling" GFCIs on the same circuit. For example, if there's a GFCI receptacle in the kitchen, and another in the garage, the kitchen GFCI won't trip and/or reset as expected. We're guessing that the GFCIs are confusing each other and the downstream receptacle should be replaced. So the kitchen would get a standard receptacle (labeled that it's GFCI protected) and the garage GFCI would remain. Also, when there's a GFCI breaker in the service panel, shouldn't the receptacles controlled by that breaker also be standard, NOT GFCI receptacles to avoid "duels" as well? Lastly, we're not talking about GFCIs for bathrooms, which are clearly discussed in code books. So any info or NEC code citations you share would be most appreciated. I'll relay your explanations on our professional bulletin board so we can all be educated about this issue. Thanks so much & I'll check back with you asap.

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#180879 - 09/14/08 08:03 PM Re: 2 GFCIs on same circuit [Re: SheBeInspector]
renosteinke Offline
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Registered: 01/22/05
Posts: 5299
Loc: Blue Collar Country
Welcome ... and feel free to visit our chat room!

There is really no such thing as 'dueling GFCI's." The presence of one on a circuit ought not have any effect on the others. As you might guess, the NEC does not specifically address this non-issue.

What might happen, though, is that ... due to manufacturing tolerances, accumulating leakage, etc ... that the GFI that trips may not be the one closest to the fault.

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#180880 - 09/14/08 08:42 PM Re: 2 GFCIs on same circuit [Re: renosteinke]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
Do you know about these guys?

http://www.nachi.org/forum/

They have discussion groups for home inspector related questions and answers that go beyond the code requirements into what your SOP will require.
Like John (Reno) says you are also welcome here.
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Greg Fretwell

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#180882 - 09/14/08 11:54 PM Re: 2 GFCIs on same circuit [Re: gfretwell]
Scott35 Offline

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Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
SheBeInspector

Welcome to ECN!

As mentioned by others, feel free to hang around and participate.
This Forum is made up of Members encompassing almost every aspect of the Electrical Construction Industry:
  • Electricians - Apprentices, Jorneypersons, Forepersons and Superintendents,
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  • I.T. and other Technical areas.


I would like to address your original post.

Q1:
 Quote:

A random poll of certified home inspectors at a state association-sponsored electrical seminar revealed that many of us find "dueling" GFCIs on the same circuit.


REPLY TO Q1:

Could you define how the GFCI Receptacles are connected on this Circuit?

A:
If they are all are simply Pig-Tailed from the Circuit, with the only connections being made to the "LINE" Terminals, then there should not be any trip issues.
This is NEC Compliant, and is a way to connect GFCI receptacles across a MWBC (Multi Wire Branch Circuit).

PRO: This type of connection allows for a "Selective Coordination" of device tripping - meaning the GFCI Receptacle which was connected to the leakage (Ground Fault) is the only one that trips. All others stay latched.

CON: This type of connection is the most expensive, as each Outlet requires a GFCI Receptacle.

B:
If there is a "First GFCI Receptacle" (Homerun to this Outlet), where the incoming Branch Circuit is connected to the "LINE" Terminals, and the rest of the Circuit is connected through the GFCI's "LOAD" Terminals, any Ground fault down stream + at the "First" device will trip that "First" GFCI - even the "TEST Button" on downstream GFCI Receptacles - provided the Downstream GFCI Receptacles are wired properly.

Connecting Multiple GFCIs through the "LOAD" Terminals of another GFCI is NEC Compliant, and will work.
It is just an expensive way of doing things - very similar to example "A" above, only the devices are wired through one or more GFCIs, so there is no benefit of "Selective Coordination" in this example.

(BTW "Selective Coordination" is a term which refers to Overcurrent Protection Devices - such as Circuit Breakers and Fuses; but the basis of Selective -vs- Non-Selective Coordination applies here.)

Q2:
 Quote:

For example, if there's a GFCI receptacle in the kitchen, and another in the garage, the kitchen GFCI won't trip and/or reset as expected.


REPLY TO Q2:
This may be due to several factors:

1: The GFCI in the Garage is not protecting the GFCI in the Kitchen (devices only connected to "LINE" side Terminations),

2: The Garage GFCI is on a different Circuit from the Kitchen Circuit(s),

3: There is a MWBC feeding the Kitchen, and the GFCIs are connected through "LOAD" Terminals,

4: The Circuit between the Garage Receptacle and the Kitchen Receptacle undergoing the Test has an Open Conductor in the Branch Circuitry (or other wiring errors),

5: One of the GFCIs is malfunctioning,

6: The GFCI in the Kitchen does not have 120VAC at it - likely to occur if the "Upstream GFCI" has tripped, and this "Downstream GFCI" is connected to it via the Upstream Device's "LOAD" Terminals.

If there is no active Circuit available at the GFCI Receptacle, the "TEST" Button does not function, and if the "RESET" Button has already perfored a reset (Re-latch), that Button will not do anything.

This scenario would require a voltage Test at the Kitchen Device, to confirm the Circuit is active.
If 120VAC is read between the two Vertical Terminals of the Receptacle, and the "TEST" Button is not functioning, the device may be defective.

There is more to this, so let me know what the parameters are.


Q3:
 Quote:

We're guessing that the GFCIs are confusing each other and the downstream receptacle should be replaced. So the kitchen would get a standard receptacle (labeled that it's GFCI protected) and the garage GFCI would remain.


REPLY TO Q3:

That would be one way to do it, which would be NEC Compliant.

Another way is to wire the GFCI Receptacle at the Garage so it only connects through the "LINE" Terminals - the Device "Taps Off " the Branch Circuit; then the Branch Circuit continues "As-Is" to the Kitchen Outlet, where another GFCI Receptacle would be installed + connected through the "LINE" Terminals only.

If there are additional Kitchen receptacles "Downstream":
The "First Outlet" at the Kitchen would have a GFCI Receptacle, with the remaining Kitchen Outlets being Standard Receptacles - which are connected through the "LOAD" Terminals of the GFCI at the Kitchen.


Q4:
 Quote:

Also, when there's a GFCI breaker in the service panel, shouldn't the receptacles controlled by that breaker also be standard, NOT GFCI receptacles to avoid "duels" as well?



REPLY TO Q4:

They MAY be Standard Receptacles, or if someone wants to do so, they MAY also be GFCI Receptacle Devices.
Both methods are NEC Compliant.

There is a "DESIGN ISSUE" with GFCI Receptacles fed from a GFCI Breaker, which results in "Non-Selective Coordination" when one GFCI Receptacle undergoes a TEST; both the GFCI Receptacle AND the GFCI Breaker may trip.

Other than that minor design issue, this would likely be the most effective way to provide Ground Fault Protection to Personnel.


Q5:
 Quote:

Lastly, we're not talking about GFCIs for bathrooms, which are clearly discussed in code books. So any info or NEC code citations you share would be most appreciated.


REPLY TO Q5:

I did not mention this before, as I am not too sure about the "Kitchen Receptacle" being used as an example here.

If the Kitchen Receptacle is one of the "Small Appliance Branch Circuits", as defined in NEC Article 210.11(C), connecting the Garage Receptacle to this would not be Compliant.
210.52(b)(2) specifies these Branch Circuits are not to have any other outlets, which eliminates the Garage Outlet.
The only exceptions are for an Electric Clock in any of the Rooms covered in 210.52, or a receptacle for Gas Ignitors + Lighting of Cooking Equipment.

The Rooms which the "Two Or More Small-Applinace Branch Circuits" include are:
* Kitchen,
* Pantry,
* Breakfast Room,
* Dining Room,
* Similar Areas (areas related to Kitchen activities).


Q6:
 Quote:

I'll relay your explanations on our professional bulletin board so we can all be educated about this issue.


REPLY TO Q6:

Great!

Tell them to feel free in discussing these items here.


Q7:
 Quote:

Thanks so much & I'll check back with you asap.


REPLY TO Q7:

Looking forward to your replies!

Hope these replies are useful.

Scott


Edited by Scott35 (09/14/08 11:59 PM)
Edit Reason: Added quote references
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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#180883 - 09/15/08 04:26 AM Re: 2 GFCIs on same circuit [Re: Scott35]
SteveFehr Offline
Member

Registered: 03/19/05
Posts: 1192
Loc: Chesapeake, VA
As already pointed out, series-connected GFCI outlets are not a violation. Maybe a waste of a $12 GFCI where a $1 receptacle would do, but there's certainly nothing wrong with it. In fact, it's even safer, as it hedges against GFCI failure. One GFCI will always trip before the other, it's just the nature of how they work.

One way to test both GFCI outlets is to simulate a N-G fault, which will route a small amount of building neutral current through the ground wire and *should* trip both GFCI receptacles. I'd caution that a properly listed device should be used for this, as it's dangerous to simply short the wires- there could be a LOT of current on the building neutral, and you don't want to route that through a #14 wire.

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#180887 - 09/15/08 07:29 AM Re: 2 GFCIs on same circuit [Re: SteveFehr]
KJay Offline
Member

Registered: 11/27/07
Posts: 763
Loc: MA, USA
Steve,
I will give insert my two cents worth and then shut my mouth.
IMO, the series installation in OP post is indeed a basic violation of NEC 110.3[B].
None of the manufactures instructions I have seen for UL listed GFCI receptacles or cb’s allow this type of connection. Generally they have only two approved connection methods and this is not one of them. I think the fact that they are having issues with proper tripping of the devices reinforces this.
Of course, this is JMHO.

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#180889 - 09/15/08 08:25 AM Re: 2 GFCIs on same circuit [Re: KJay]
SteveFehr Offline
Member

Registered: 03/19/05
Posts: 1192
Loc: Chesapeake, VA
KJay, I disagree, this is not a violation of NEC 110.3. The method of ground fault, overload or overcurrent detection at any point upstream has no bearing on the listing. A GFCI receptacle is no different than ground fault detection on a switchboard, or the ground fault detection integrated into an AFCI breaker, both of which are unquestionably acceptable to feed a GFCI receptacle.

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#180891 - 09/15/08 09:51 AM Re: 2 GFCIs on same circuit [Re: SteveFehr]
KJay Offline
Member

Registered: 11/27/07
Posts: 763
Loc: MA, USA
Steve, I clearly see your point.
But, my only contention was that this receptacle contains ground fault protection for persons [GFCI] with instructions that clearly show connection diagrams with only other non-gfci receptacles connected downstream of it. IMO, installing a second GFCI receptacle downstream of this first GFCI receptacle would be a violation of the listed instructions included with this first receptacle.
This is no way should be construed as saying that you couldn’t have another piece of listed equipment with its own GFCI protection utilized downstream, but I don’t believe that a second GFCI receptacle would be allowed, at least according to the included instructions.

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#180893 - 09/15/08 10:20 AM Re: 2 GFCIs on same circuit [Re: KJay]
electech Offline
Member

Registered: 02/18/02
Posts: 113
Loc: Northern Il
"I will give insert my two cents worth and then shut my mouth."

Easier said than done! (I know how that is...)

The NRTL Listing report may contain specific paragraphs taken from the manufacturer-submitted user documentation. This would be to prove safety standard compliance in the case where a safety standard clause states the user documentation must present certain specific information. These instruction are typically minimums. Other installations may not violate a listing.

In this case, UL943 clause 8.1 details what needs to be stated. "8.1.1 There shall be plain, legible, and durable instructions for effective use of a ground-fault
circuit-interrupter" I don't want to post too much for copyright reasons, but clause 8.1.x directs you to annex E for some specific required info: MFG name, "To prevent electric shock or electrocution, always turn the power off...", "Do not install this GFI receptacle on a circuit that powrs life support...", etc. I don't see anything disallowing mutliple GFI's, but I don't have time to look right now. This is lunch break and I have some important cigarettes I need to smoke. Probably too busy at work today, but I'll browse the standard tonight (if I don't get too distracted at home).

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#180895 - 09/15/08 11:30 AM Re: 2 GFCIs on same circuit [Re: electech]
SheBeInspector Offline
New Member

Registered: 04/23/07
Posts: 3
Loc: California
It's a thrill to be runnin' with the big dogs! Thanks for your replies, and I apologize for my vague, incorrect and/or sloppy electrical nomenclature. I'll work on it. Now, back to the "dueling" GFCIs:
I found separate breakers for the kitchen & garage in the service panel and the kitchen countertop GFCI tested as 120v, "wiring OK" with my Sure-Test, as did the garage GFCI.

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