Gfci breaker on gfci outlet

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publicgood

Senior Member
Location
WI, USA
If you want them to fight each other, sure. This is no different then feeding a gfci receptacle with a gfci receptacle. 4-6mA is not a wide window.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If you want them to fight each other, sure. This is no different then feeding a gfci receptacle with a gfci receptacle. 4-6mA is not a wide window.
I wouldn't exactly say that they fight each other, but either one alone or both together could trip on any fault, and if they both trip you will have to reset the upstream one first.

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al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Is it ok to feed a gfci outlet with a gfci breaker ?
There is no interaction between one GFCI and another, unless one is faulty in some ground-faulting manner. Set that idea aside and let's imagine some scenarios where all the branch circuit wiring and GFCIs are good.

The GFCI receptacle will trip with a leakage, let's say, of 5.12 milliamps that can come from whatever is downstream of it.

The GFCI breaker will trip, let's pretend, at 5.3 milliamps.

Now the branch circuit has a couple other outlets on it between the GFCI breaker and the GFCI receptacle, and the branch circuit conductors are each about 55 feet long between the breaker and receptacle. There will be a capacitive "leakage" to ground along the 55 feet. Lets say that is 0.1 milliamp.

If no load is connected to any of the outlets between breaker and GFCI receptacle, and a ground fault downstream of the GFCI receptacle of 5.15 milliamps occurs, the receptacle will see 5.15 milliamps, and the breaker will see 5.25 milliamps. The receptacle will trip.

Now, let's add a cord and plug "thing" to one of the intermediate outlets between the GFCI breaker and the GFCI receptacle, a thing that has a ground fault "leakage" of 0.2 milliamps. Now, a ground fault through the GFCI receptacle of 5.05 milliamps occurs, the GFCI receptacle will see 5.05 milliamps and not trip, and the GFCI breaker will see 5.35 milliamps and the breaker WILL trip.

Moral of the story: It's hard to know, without careful circuit analysis, which GFCI will trip. The end user will probably find their behavior to be a mystery and hard to live with.
 
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bluecollar84

Senior Member
Location
US
The reason I am wiring it this way is: I'm adding an outlet outside to a pool deck using existing conduit that already has gfci protected branch circuits so I need to gfci protect the circuit I am adding in that conduit it comply with 680.23 f3 code article. Now I can't find any WR/TP rated outdoor outlets other than gfci outlets that's why I'm using both at the breaker and at the outlet. Anyone see a way around this ?


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publicgood

Senior Member
Location
WI, USA
Adding to al hildenbrand's comment about leakage current. Not only will the branch circuit have leakage current, but the cord and plug devices plugged in have a UL allowance of typically up to 0.5mA leakage current.
 

retirede

Senior Member
Location
Illinois
Gfci breaker on gfci outlet

I have seen WR/TR standard (not GFCI) duplex receptacles.

Edit - Just realized you said "TP", not TR". Sorry.
 
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JFletcher

Senior Member
Location
Williamsburg, VA
The reason I am wiring it this way is: I'm adding an outlet outside to a pool deck using existing conduit that already has gfci protected branch circuits so I need to gfci protect the circuit I am adding in that conduit it comply with 680.23 f3 code article. Now I can't find any WR/TP rated outdoor outlets other than gfci outlets that's why I'm using both at the breaker and at the outlet. Anyone see a way around this ?


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http://www.homedepot.com/p/Leviton-...t-Duplex-Outlet-White-R62-W5320-T0W/202078774

Unless Im missing something you do not need TP (tamper-proof, which dont exist afaik) receptacles, just WR/TR.

Running double GFCI protection is okay, tho the HO should be aware there are two places to check if there is no power.
 

jap

Senior Member
Occupation
Electrician
I'm still trying to figure out why if it's simply an existing conduit that's being used to add a dedicated circuit why it would have to have the GFI Breaker at the beginning.

But I'd have to read up on it.

JAP>
 
GFCI manufacturer testing requirements

GFCI manufacturer testing requirements

I work in a hospital, which has over 500 GFCI receptacles. The manufacturer requires a monthly manual test on each of these GFCI receptacles, noted on the GFCI face and in the enclosed literature. This is an enormous drain of resources to have an electrician preform this task each month (roughly 30 man hours). We are obligated to have electricians perform the task because of job description in a union environment.

A few years ago the manufacturers added the self testing feature:When the circuit detects an issue, it flashes red andcontinues to check the circuit to see if the issue has gone away. If the issuepersists, then the unit will trip and lock out (and continues to blinkred). This process can take up to 7-minutes from the time the issue isdetected until the unit trips and locks out. At this point there is no power at the face of the receptacle, this appears to me to be a "fail safe" test and clearly is a superior method of testing than having a manual test performed each month. I would like to hear your thoughts on this issue and see how we can go about petitioning the authorities to re-evaluate the testing constraints.

Thanks
Kenny


 
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