GFCI Ponderings

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.

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.

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(?)!

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....

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.

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

@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! :-)

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...

@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!

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.

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

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.

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 :-)

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.

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

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