GFCI ON GFCI

B

boblhead

Member
Location
New Hampshire
Occupation
Electrician
Any issues with having GFCI receptacles on AFCI/GFCI breakers? Customer wants to make wiring as safe as possible in old family seasonal cottage. Much of the existing wiring has no ground
 
It can be confusing to troubleshoot, but it's okay electrically and code-wise.

There is no advantage to cascading them. It's only extra work and expense.
 
Is the interior finished? Is there an accessible crawl and/or attic space? Protecting existing non grounded circuits with a GFCI is no longer code compliant. If you change out a 2 wire receptacle from 2 wire to 3 wire grounding you have to run an Equipment Grounding Conductor to one of several places the US National Electric Code (NEC) now allows. Even the GFCI, unless you use a blank face model in a double gang box, changes that receptacle to 3 wire thus invoking the requirement for an EGC to that box.

If they really want maximum safety give them a price on rewiring it. If there are baseboards you can remove them, cut out the portion of the wall sheathing that is behind the baseboard while leaving a 1/2 inch of finish at the bottom edge so all of its bottom edge will be below the top of the baseboard when you reinstall it, and drill holes above the top of the baseboard through the studs by angling the body of a right angle drill upwards above the bottom of the wall sheathing.

[If the interior wall sheathing turns out to be 1/4 inch wood paneling, as that of many summer cottages are, do them a big favor and convince them to have it removed. When that thin siding is mounted directly on the wood framing the rate of fire spread over the surface is faster than a healthy man can run. Ignition to flashover can take as little as 20 minutes. That is when the entire remaining contents of the room burst into flames simultaneously. The compartment is then said to be "fully involved" in fire. When firefighters hold a structure fire to the compartment of origin it is said they made a "Good Stop." once the compartment of origin flashes over it will force fire out the door in imitation of a blowtorch. They would be lucky to save the remainder of the house.]

Once you run the new cable then install a backing board to the baseboards back side to keep the same reveal on the baseboard top and put them back in with screws. Strips of CD plywood or even oriented strand or particle board work well for this and give you a wide range of thicknesses to choose from The advantage of using a spacing plank behind the baseboard is that you can attach the baseboard to the spacing plank and fasten them both to the wall framing with the same screws. If you countersink the screws back of the front of the baseboard you can then cover the screw heads with the push in plastic plugs which most closely match the baseboards. Cables can also be run behind door and window trim without a huge amount of trouble. All it takes is a somewhat thick piece of roof flashing to guard the cable from nails and screws. I've had inspectors except doubled up flashing to get the required thickness.

Tom Horne
 
infinity said:
No issues besides what Larry mentioned. Electrical myth that they will nuisance trip.
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The nuisance is when there IS a trip, and you don't know that there are two GFCIs in the circuit. So you go to reset the GFCI outlet and it doesn't reset, then you start troubleshooting it, only to (eventually) discover that there is a pointlessly redundant GFCI breaker feeding it that had tripped.
 
hornetd said:
Protecting existing non grounded circuits with a GFCI is no longer code compliant. If you change out a 2 wire receptacle from 2 wire to 3 wire grounding you have to run an Equipment Grounding Conductor to one of several places the US National Electric Code (NEC) now allows.

Tom Horne
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Where is that requirement in the code? I don't see it in the 2023 NEC 406(D)(2)

Ron
 
Jraef said:
News to me. Care to cite a reference to that?
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Part VII. Methods of Equipment Grounding
250.130 Equipment Grounding Conductor Connections.

The reference I site is Read twice before believing what you think.

hornetd said:
Protecting existing non grounded circuits with a GFCI is no longer code compliant. If you change out a 2 wire receptacle from 2 wire to 3 wire grounding you have to run an Equipment Grounding Conductor to one of several places the US National Electric Code (NEC) now allows. Even the GFCI, unless you use a blank face model in a double gang box, changes that receptacle to 3 wire thus invoking the requirement for an EGC to that box.
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Dammit Gumby I missed 1 word in this section and that was "Permitted" rather than required. My humble apologies to all hands!

Tom Horne
 
Jraef said:
The nuisance is when there IS a trip, and you don't know that there are two GFCIs in the circuit. So you go to reset the GFCI outlet and it doesn't reset, then you start troubleshooting it, only to (eventually) discover that there is a pointlessly redundant GFCI breaker feeding it that had tripped.
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I once found three in-line on one circuit doing a trouble-shoot: living room, hallway, and bedroom.
 
LarryFine said:
I once found three in-line on one circuit doing a trouble-shoot: living room, hallway, and bedroom.
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In my son's new to them home the home inspector called out 3 different bathrooms for not having GFCI receptacles. Not knowing any better than to take home inspectors utterances as the standard of truth in real estate the seller went ahead and put them in. I know he did it himself because each one was wired to protect the rest of the circuit. I dare to hope that an electrician would have toned out the circuit and informed the owner that their was no problem because the circuit had been protected by the first receptacle on the circuit which also picked up the 3 bathrooms and the rear outdoor receptacle. That's 5 GFCIs in series. I get out to the new house and my daughter in law is asking if I can tell why so many receptacles were dead. I came back the following Saturday and made some guesses based on the experience I gained in the 1970s when GFCIs were a lot more expensive. In tract housing the first required GFCI going out from the Main panel was were that expensive part was installed. After that it would travel as short a route as it could through bathrooms out door receptacles and each place one became required since then. As I found each one I removed the excess cable jacket, overlong wires, and ugly splices and spliced the circuit on through with pigtails to the line terminals only. There are just as many GFCIs but now if one trips off the occupant in the room were it's located can hear the snap and when they check the plug in the outlet they can see the red edge of the reset button sticking out of the face of the GFCI.

In my unhumble opinion GFCIs should be in the room with any outlets they protect, or in the panel were that branch circuit comes from and nowhere else. Installing them in another room from a receptacle/s they protect is just another way to needlessly irritate the occupants.

Tom Horne
 
hornetd said:
In my unhumble opinion GFCIs should be in the room with any outlets they protect, or in the panel where that branch circuit comes from and nowhere else. Installing them in another room from a receptacle/s they protect is just another way to needlessly irritate the occupants.

Tom Horne
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That’s probably good design practice when practical, but no way that should be an NEC requirement.
 
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