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GFCI Ponderings

10/09/2017 5:21 PM

I recently purchased an old home with, let's just say, 'not good' wiring...

Standard 100 amp, 220v service. Most of the wiring is 12-2 fabric with 16 gauge ground. It appears the service was 'upgraded' to a CB panel at some point because there is modern romex in the panel, but all of the fixtures/boxes have the fabric wire.

Many old and 2-prong outlets, so I started replacing them... To my horror, I found that many were using the 16 gauge ground as neutral (see photo below). Lots of other issues, and I won't get into those, but needless to say EVERY outlet, accessible junction box, and circuit breaker was carefully checked and re-jiggered as needed.

Since two of the circuits serve the bathroom and kitchen, I wanted to install GFCI breakers for them at the panel, but even after all of my hard work I was dismayed to find they would instantly trip as soon as anything was plugged into them (notably they worked fine on normal circuit breakers and tested good with an outlet tester).

Eventually after much cursing and maybe a little bit of crying I figured out that somewhere buried in the walls, neutral is still bonded to ground somewhere OTHER than than panel or any of the outlets or accessible junction boxes.

I debated on what to do, but eventually decided to be lazy and rather than tear the walls up I would just install GFCI outlets at the first outlet of each string to at least provide some protection.

Here are my questions:

  1. Is installing a GFCI outlet at the start of a hot-neutral only circuit 'good enough'? I know (think) it's technically allowed with the "No Equipment Ground" sticker, but is it actually safe if someone drops the hairdryer into the sink? Or do I really need to go and find and eliminate the culprit? Alternatively, would it be acceptable to run a separate ground wire from each GFCI outlet directly to the ground rod outside? I'm fine leaving the sticker - I just want it to be safe.
  2. As you can imagine, once I fixed the outlets, all of them tested 'good' using a standard outlet tester (correct polarity, no open neutral, no open ground). The only way I realized there was even a problem was when I attempted to install the GFCI breakers in the panel. My question is: Other than installing a GFCI breaker, is there any standard way to test for this condition? The only thing I can think of is to un-bond the neutral bus from the box and test for continuity between neutral and ground... but is there a device that tests for this condition specifically? Or is this just one of those things that anyone with an ounce of sense would do at the outset?

Here's what I found in almost every box:

Thanks for reading!

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#1

Re: GFCI ponderings

10/09/2017 5:25 PM

I might add that I suspect the problem is the idiot who replaced the fuse box found that the existing wires were too short and just added 1-2 foot lengths of romex, but joined neutral and ground together. If you tell me to actually fix the problem, my first plan is to tear into the wall around the panel.

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#16
In reply to #1

Re: GFCI ponderings

10/11/2017 10:05 AM

You can test this theory by installing a GFCI in the first outlet of a string of outlets and downstream the rest to protect them all. Hook up the 16 gauge ground wire to the GFCI as the equipment ground. If it doesn't trip, the neutral-to-ground problem is between the panel and the first outlet. If so, I would open up the wall around the panel, find out what's wrong and correct it.

Also, if you decide to install a GFCI in the first outlet as a permanent solution, this will provide protection and you are not required to install the 'no equipment ground' sticker since you have a 16 gauge equipment ground wire. This will provide protection to all the outlets in that string as long as you connect the downstream outlets to the second set of terminals on the GFCI. The only thing not protected would be the wiring between the panel and the first outlet, which isn't required to be GFCI protected. Most new houses are wired this way.

If it were my house, I would not replace all the wiring. Since you have a ground wire (even though it is smaller than current Code requires) you can make this safe by properly connecting the existing wire.

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#18
In reply to #1

Re: GFCI ponderings

10/14/2017 9:34 AM

With your photo of the ground wire on the receptacle, I wouldn't be surprised if the neutral was open, and the outlet didn't work as wired after the service was changed. So rather than fix the open circuit, just return the current through the ground wire, easy-peasey, just rewire all the outlets(?)!

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#2

Re: GFCI ponderings

10/09/2017 5:45 PM

Working as an electrician for many years I can tell you I have seen this many many times....The best thing to do , if you can manage it, is to replace all the wiring....now having said that, sometimes it's not worth the effort without doing a full remodel of the house and possibly altering the floor plan and consequently the wiring scheme...but sometimes you can run emt through the attic space and down the walls... sometimes that's just not possible...If that's the case then you are faced with what's the best course of action for you, wait and change all the wiring in a future remodeling effort, or go for it now....or just live with it...In any case I wouldn't lose any sleep over it....

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#3
In reply to #2

Re: GFCI ponderings

10/09/2017 6:00 PM

Also as an ex-electrician, I have to agree with SolarEagle. Most likely the original wiring was "knob and tube", which was run in what's called a "Multi-Wire Branch Circuit" (MWBC) where separate hot likes from the fuse boxk shared a common neutral with a single return run to the panel, something easy to implement when running separate individual wires (i.e. pre-Romex). Later when it was upgraded, rather than bite the bullet and pull new Romex everywhere, they tried to tie into the existing MWBC circuits, only to find out that they had no neutrals in most of them once the home run was used somewhere else. So they got "creative" and just used the ground wires out of convenience. That problem is, as you suspect, so deeply embedded into the walls and attic spaces that it will be virtually impossible to trace it all down, plus it is dangerous because those ground wires are now "current carrying conductors" instead of "safety ground". It's far far easier to just pull new wires everywhere.

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#5
In reply to #2

Re: GFCI ponderings

10/10/2017 1:33 AM

@SolarEagle --

Thanks so much for the thoughtful reply. The home is going to be a rental, and my primary interest is first making the home safe for the tenants, and secondly to protect the house from burning down to the extent I can.

It sounds like you're saying it's 'safe enough' to have a GFCI outlet at the start of the run, even if the 'supply' is hot-neutral only? -- is that correct?

I totally agree that the 'right' choice is to rewire the entire home, and I'm definitely capable of that (I could probably do it even without EMT if we're willing to ignore stapling requirements), but I'd rather not if I can safely avoid it.

@JRaef --

I'm quite sure it's not knob and tube wiring... I've been in the attic and in all of the junction boxes and it's all the criss-cross black fabric-wrapped 12 gauge with 16 gauge ground. The only place this wire doesn't appear is in the CB panel, which is all 90's era white 12-2 romex with full size ground. As I said in my first reply I believe the white romex was just used as an "extender" and (improperly joined) to the existing fabric wires (that presumably went to an original fuse box). Those junctions I believe are hidden behind the wall right next to the fuse box.

So, I think grounds and neutrals are/were available everywhere for all circuits (Except for one, which was 'two circuits in one' using a 12-3 wire to power two 'branches' with a common neutral. Those two have been combined into one and the red wire is capped and retired.)

Regarding the ease of pulling new wires, crazily I think I'm close to having everything right - I just need to figure out why the neutrals are bonded to grounds in the run between the CB panel and the first outlet/device. Beyond those, everything seems great.

@Rixter --

Thanks for the explanation on the GFCI breaker, and I'm 99% sure the breaker is tripping because there is a bond between neutral and ground somewhere near the CB panel. The question for me remains: Does attaching a GFCI to a shorted neutral-ground 'feeder' make the rest of the run safer? Or did I just waste $40 on outlets?

Thanks everyone for your kind responses!

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#6
In reply to #5

Re: GFCI ponderings

10/10/2017 3:14 AM

There are different levels of safety....Your wiring is not up to code, it is grandfathered in...If I was to guess there was probably no permit pulled on the panel replacement, and that could mean it was done improperly...that alone is cause for concern from a liability standpoint...If it was just you living there, you might let it slide but as a rental your responsibility here is taken to a new level, and it should be brought up to code...I suggested EMT because it's easier to pull wire through and it protects the wire and the possibility of a wire being damaged or overheating and in contact with the wooden structure of the house and possibly starting a fire....with conduit you can run thhn wire which is much better than romex....plus the conduit protects the wire from rodents and insects that could damage the insulation....The GFCI receptacle is better than just a 2 prong plug, so it is an improvement...You should be able to trace down where the neutral is tied into the ground, but to correct the situation will probably require running a separate ground wire which might not be an easy task....you should study any and all the ways that you can get to the wiring, and pick the path of least resistance...good luck

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#7
In reply to #6

Re: GFCI ponderings

10/10/2017 7:51 AM

@SolarEagle --

Again, your comments are very much appreciated. Thank you.

Yes, conduit/new wiring would be ideal - I didn't mean to imply that I disagreed, and I'll definitely go that way if that's what you suggest.

However, theoretically, if I'm able to definitively isolate the neutral-ground issues and fix those, and I'm able to 100% assure myself no circuits are mis-wired, can I be comfortable using the old 12-12-16 wiring? I honestly feel that if I break open the wall next to the panel there's a 80% chance I'll find that the clown before me just gathered up the neutrals and grounds and twisted them all together. However, if I'm wrong and I can't find the issue I've already got the wall open and rewiring just became a lot easier, in which case I'll just buy a 500' roll and get to work (conduit is going to be iffy on the outside walls as there isn't enough space between the roof decking and the wall top plates to slide a piece of conduit down the wall - I'd likely have to just tear down drywall in several places in each room).

To be clear, you have convinced me that it's NOT okay to leave the wiring as it is today -- too much liability and risk with no separate path to ground. I will not rent it out until at least that is remedied. The big question for me is whether it is worth the additional time and expense to completely rewire.

PS - I would also consider changing all of the circuit breakers from 20A to 15A just to reduce the chances of overcurrent that much more if you think it's necessary.

Thanks again so much for your time and attention! :-)

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#8
In reply to #7

Re: GFCI ponderings

10/10/2017 1:39 PM

The #12 romex should be good for 20 amps, no need to reduce breaker size...I guess we'll know more when you've found out how the panel upgrade was done...I certainly don't like the idea of all those splices done in the wall, if in fact that is the case....And about running conduit down the walls, that's what I meant by finding the path of least resistance, sometimes you can go up or go down or even outside....I don't know how the house is built, but I have had to run wire in pretty much any way you can imagine...including adding external subpanels and conduit around the house, sometimes high, sometimes low....but none of this may be necessary....one step at a time...

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#11
In reply to #8

Re: GFCI ponderings

10/10/2017 5:28 PM

@SolarEagle - Yes, for sure I will tear into the wall and attempt to fix it this weekend (the rentals are my 'side hobby') and I'll report back to you on the outcome (with pictures).

And yes, I imagine if I have to go for the full re-wire there will have to be some creative problem solving :-) Fortunately there is ample crawl space!

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#4

Re: GFCI ponderings

10/09/2017 6:31 PM

With proper wiring, all of the current that flows out the hot wire returns through the neutral wire. No current should be flowing through the ground wire. It is there only for safety. The GFCI detects the difference between these two currents and opens the circuit if they are unequal.

The GFCI detects the difference between the hot and neutral currents and opens the circuit if they are unequal. If there is a current path between either hot or neutral to ground, the GFCI will trip.

http://aliveandbloggin.com/gfci-wiring-diagram.html

I don't know what is legal where you are, but my house (30 years old) has outlet GFCI devices for bathrooms, kitchen, and outside power outlets. There is one GFCI outlet in the kitchen (for inside outlets) and one in the garage (for outside outlets) which protect the circuits from that point on.

You might want to invest in a clamp-on ammeter. With a load on the circuit (e.g. a lamp), you should read no current if it is clamped around both hot and neutral. Perhaps you can find where the neutral is grounded.

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#9

Re: GFCI Ponderings

10/10/2017 2:12 PM

I feel for you. I think if you want this set to right, it will be your dime, and more than a pretty penny.

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#10

Re: GFCI Ponderings

10/10/2017 2:34 PM

If this house has high baseboards AS WELL AS plaster and lathe walls, you may be able to remove the baseboards and remove the plaster and lathe for about 4-6 inches from the floor, on both sides. Plaster and lathe uses ~one inch This will give you a good accessible wire path at the bottom so you can drop wires as needed and staple flat 3 conductor wire there. When finished use a spacer to allow you to place some 1/2" drywall under the baseboards so the wires uses the other 1/2 inch. I replaced the old nails with screws at top and bottom.

I once bought a house with old ceramic knob and tube wiring and I wanted to upgrade it. I did it this way and it went quickly once I got the procedure down. You could even eliminate the drywall under the baseboards, but I wanted it to be a proper job.

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#12
In reply to #10

Re: GFCI Ponderings

10/10/2017 5:31 PM

Great tips! Fortunately (unfortunately?) the house is standard 2x4 construction with drywall. If I have to re-wire I may end up just going for the "steampunk" look and run exposed conduit right on top of the walls :-)

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#13
In reply to #12

Re: GFCI Ponderings

10/10/2017 7:16 PM

Nah, there are some great videos on Youtube about how to pull new wires into existing walls. It's not as difficult as you might think. You may need to buy a couple of new tools.

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#14

Re: GFCI Ponderings

10/11/2017 7:42 AM

Rip it out and start again, I wouldn't risk any of the wiring, run all new, If you do it whilst leaving the old stuff in situ you can put new points and switches where you want & when you've finished cut the old wires remove the old points fill the back boxes this will save having to rip the cables out of the wall then connect the new runs to the distribution box. You don't say if you are an electrician, if not you will need to get one.

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#15
In reply to #14

Re: GFCI Ponderings

10/11/2017 9:08 AM

Bazzer is right! A good electrician will knock this out in a jiffy, and set up the removal of the old for you.

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#17

Re: GFCI Ponderings

10/11/2017 10:06 AM

Truthsmiles,

I appreciate your keeping up with the replies to your question. I'll add a few thoughts:

  • In addition to detecting and tripping on a current imbalance of 5mA or more, GFCI's will also trip if the resistance between neutral and ground is typically less than 25-ohms. This often happens when wiring gets wet in a box. In your case I believe you are correct that the wires were tied together somewhere. But it could also be an accidental contact between the neutral and the bare ground at a receptacle (I've run into this more than once).
  • In the NEC, a GFCI receptacle is completely OK as a replacement for any receptacle that is not grounded, even though it would not have a ground connection. This is because it will trip on the current imbalance.
  • Anywhere that you still have the 16-AWG ground wire being used as a current-carrying conductor you have a very real risk of a fire. The 16-AWG wire is only capable of carrying 8-amps. It doesn't matter if your breaker is 15 or 20-amps!
  • Putting GFCI receptacles at the outlets instead of at the breaker is OK and is usually less expensive, but they take a lot of space in the outlet box.
  • When installing a GFCI receptacle pay very careful attention to the Line and Load markings and make sure the incoming power goes to the Line. Downstream receptacles wired to the Load will be protected; if wired to the Line they won't. The NEC would require protected downstream receptacles to be marked with a tag saying that they are GFCI protected.
  • From the general statements you have made, I suspect your house was built sometime after WWII, probably in the mid 1950's to early 1960's.
  • Rewiring is a good alternative, but gaining access to the existing walls is always a challenge. Not hard if the basement is unfinished, but much more difficult if two-story. Many very useful tools exist for doing this with hardly any holes in the walls being left for filling. Any abandoned wiring has to be properly insulated also.
  • I agree with the comments about being more careful because it is a rental house.

--JMM

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aurizon (1); Bazzer Englander (1); James Stewart (2); jmueller (1); JRaef (2); Rixter (1); Robert V (1); rwilliams (1); SolarEagle (3); truthsmiles (5)

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