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Old House Ground Wire

Posted by rileyann (My Page) on
Fri, May 16, 14 at 0:00

My house was built in 1956 and during some electrical upgrades, I've noticed this wire running from jbox to jbox. It's about the same gauge as a wire coat hanger. The photo below is after I upgraded to a deeper plastic box so the GFCI would fit easier, but is the purpose of that wire to ground the old metal jbox? And is that different than a green or bare grounding wire now included in romex? My house wires only have a white and black wire.

Thanks,
R


Follow-Up Postings:

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RE: Old House Ground Wire

Here's a photo of that grounding wire and the illegal wiring (I didn't do it, I swear!) of my cooktop hood, which I am replacing soon. That grounding wire, if in fact that is what it is, looks like a gerry-rig way to do things so I'd like to do something different to ground the vent.

Can I cut the 2-wire romex up in the attic, put it in a metal box, connect that old grounding wire to the box, connect new 14/2 with ground wire romex to the old romex, run the new romex through flex conduit down into my cabinet and into the cooktop hood's jbox? One end of the romex ground wire will be connected to the hood's wiring and the other end will connect to the metal box in the attic. Is that the way to do it? I like the idea of using conduit in the cabinet for wire protection, but isn't there a better way than threading romex through flex conduit?

Thanks!


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RE: Old House Ground Wire

here's the photo of the illegal wiring I mentioned above.


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RE: Old House Ground Wire

It is a permissive thing to allow a separate ground wire to ground extensions to ungrounded branch circuits. It is preferable however to run grounded cable back to the place where there is a more reasonable ground. Never however, assume that a metal box itself is grounded in such retrofits. It may not be.


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RE: Old House Ground Wire

rileyann:

As ronnatalie mentioned, it is permissive to run a separate ground in what had been ungrounded systems.

RE: Range Hood
Your plan to terminate the 2 wire with external ground in the attic at a Jbox and then bring down 14/2 w ground is reasonable as long as the box is accessible. In that box you want to wire nut 3 ground wires together (the old external ground, the new ground and a short ground wire attached to the metal box). If you are using #14 wire the breaker must not be more than 15 amps on that circuit.

My concern is with the GFI you installed. It does not appear to be connected to the ground wire.


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RE: Old House Ground Wire

Thanks to both of you! When I bring the external ground into the box in the attic, does it need its own clamp or can I thread in the same knockout/clamp as one of the romex? How do I know if the external ground is really doing anything? If I turn on the power and put one end of the tester on the hot and the other on the box, is it grounded if the tester lights up? The box will be accessible, but only if you're in the attic. I assume that's fine. Also, it is a 15 amp breaker.

Regarding the GFI that I installed, I figured that the old outlet wasn't directly attached to it so the GFI didn't need to be. And now that the box is plastic there was no need to attached it to the box. Is this bad? it GFI functions correctly when I test it.


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RE: Old House Ground Wire

"can I thread in the same knockout/clamp as one of the romex?" -- Yes, it's probably the only way you could clamp it.

Regarding GFI: The GFI has a ground prong. It has to be grounded. The GFI portion may function properly without the ground, but whatever's plugged into the outlet still isn't grounded. (Edit: On closer review, if you have an ungrounded two wire system, you can install a three-prong GFI if it's marked "No equipment ground".)
In this case you have a ground wire available, albeit external - you need to use it.

Just to be clear also, when you are working with ground wires, it's not enough just to connect to the metal box. You need to wire nut the ground wires together AND make a connection to the device (ground screw) and box if it's metal. You can't depend on the mounting screws on the outlet to provide the ground connection from the metal box to the outlet ground.

This post was edited by jakethewonderdog on Fri, May 16, 14 at 10:32


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RE: Old House Ground Wire

"..when you are working with ground wires, it's not enough just to connect to the metal box." - So do you think that back in the 1950s they thought they were grounding the device by doing it this way? Seems like they should have known better.

So how do I test to see if the external ground wire is really doing it's job?


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RE: Old House Ground Wire

"So do you think that back in the 1950s they thought they were grounding the device by doing it this way?" -- I think that it's an evolving understanding of how to make things safer. The other thing you see even from the 70's is people who lightly twisted the ground wires and called that good.
While it may have shown as grounded, when you passed a high current ground fault through it, the connection failed.

Which brings us to your second question: If you really want to test the ground, the way to do it is to pass a significant amount of current through it. You can do that by wiring up a test plug that you can connect a load to (a 200 watt light bulb in a pigtail, for example). The test plug would go use the hot side of the outlet and the ground prong instead of the neutral. It would be a crude test, but it would work,


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RE: Old House Ground Wire

Slightly OT but my house is also from the 50s, a bit earlier actually. My home inspector, who was a former electrician and spent over 5 hours on it, said all the grounds (he opened most of the receptacles) were good, even the ones on the older wire. I can't remember the name but he said the wire was a kind that was relatively new and was still considered safe, unlike what would have been used pre-WWII. That being said, when I'm back to having more money than I know what to do with, I'm thinking of replacing all the breakers with Arc Fault units, just to be on the safe side. (all of the major appliances were rewired with modern wire, as you would expect, since 50s appliances didn't use so much current. The kitchen is mostly new wire.)

So my question...was the 50s the turning point, some houses having modern grounding and some not?

I've been watching some of Mike Holt's videos on youtube about grounding. VERY fascinating. I probably knew more than some people did (I did know, for example, that the electrons are trying to get back to the source, not back to the Earth. It just so happens that the earth is a another viable path) but I didn't know the resistance of a ground rod, even a very proper deep one, is quite high and that you can often directly jumper a circuit to one and it will only draw a couple amps or so. I would have thought going direct to ground would instantly trip most breakers. It makes these cases you hear about with stray currents make more sense, I remember a few years ago a girl was killed in Baltimore by touching a fence and that at the time I thought "wouldn't it be grounded"?

Here is a link that might be useful: https://www.youtube.com/watch?v=Yg6G5VUSsWA


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RE: Old House Ground Wire

What you said about earth grounds being high-resistance is true... and many people are confused about grounding.

In residential wiring, the ground is an alternative - low resistance - path back to the neutral conductor on the panel (and thus to the utility transformer). Low resistance is key here - it has to be able to carry the full ground fault current until the circuit breaker trips. That's why you can't have grounding conductors simply twisted together or depend on mounting screws that may not be tight to provide a low resistance ground path.

In addition, that neutral conductor must be bonded to an earth ground so that there's no potential difference between the system ground (metal on a kitchen stove, for example) and the earth ground (that might be found on the kitchen sink, for example).

Since an earth ground is high resistance, it's never a substitute for a properly bonded grounding path back to the neutral bus bar and to the utility transformer.


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RE: Old House Ground Wire

Further, lots of metal things (like those water pipes) etc... are required to be bonded just to assure things are at close potential.


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RE: Old House Ground Wire

So I made most of my electrical upgrades but while I was installing one of my GFIs making sure I had the line and load wires attached to the correct terminals (checked it four times), the GFI would not let me reset it (it comes tripped from the factory). I re-wired it using one set of pigtails and bypassing the load terminals and it works fine.

After doing some research, it sounds like the device sensed a ground fault downstream. There's only one outlet downstream of the GFI and it provides power to the batch-feed garbage disposer and a dishwasher. My outlet tester shows that the downstream outlet is wired correctly, so what could have caused the GFI to not reset when I had the load wires connected to the load terminals?

Thanks!


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RE: Old House Ground Wire

Never be surprised at what people do to "upgrade" their wiring. The pic below is in a remodeled 2-wire bathroom with all metal plumbing, so someone thought to install a 14 gauge copper wire daisy chained from outlet to outlet to fan to switch and so on until it you can see that it found it's ultimate secure grounding point.

Then they put in 49 cent devices. This is perhaps my all time favorite remodel pic.


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RE: Old House Ground Wire

That's not a ground wire, that's a pipe support... lol.


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RE: Old House Ground Wire

That's funny! Can someone give some feedback on my GFI question above?

Thanks.


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RE: Old House Ground Wire

rileyann:

You are correct, there is a ground fault in the wiring downstream in either the dishwasher or the garbage disposal - at least enough to trip the GFI.

What that means is there is some electricity leaking from the hot to the metal part of the casing on the DW or GD.
Sometimes major appliances can nuisance trip a GFI without being defective- but my guess is that it's actually a defective DW or GD if it's happening while the appliance is off.

These appliances are not required to be protected by a GFI - and it's usually not recommended because of nuisance tripping; However, they absolutely must grounded - since you don't want the sink or dishwasher to have a potential difference because a bare wire is touching an ungrounded metal frame. It could kill you.

New electrical code would not permit them on the same circuit as the small appliance outlets - perhaps you should consider a run of new, grounded romex back to the panel for the DW / GD so that you can be sure it's grounded and also solve the GFI problem as well as get these things off of the small appliance circuit.

All by themselves the DW and GD can max out a 15 amp circuit. They shouldn't be sharing the counter-top receptacles even if you aren't trying to bring it completely up to current code. Run a new 20 amp circuit for them.

This post was edited by jakethewonderdog on Fri, May 23, 14 at 18:29


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RE: Old House Ground Wire

Thanks jakethewonderdog. That's scary! Plus, the fridge is on the same circuit! But we've never tripped a breaker. For purposes of identifying the ground fault, if I rewired the GFI connecting the line and load terminals and unplugged the DW, then the DW would be the culprit if the GFI let me reset it, correct? We are installing a new DW as part of our remodel and the GD is about 6 years old.

I guess I could run a new 20 amp wire in the crawl space under the house, but it seems like it would be tough drilling through the floor from under the house in just the right spot behind the cabinets. Any tips beside tearing out the back of the cabinet?

Hooking up the the breaker is a job for a pro though, right? But that should not take someone very long if the wire is already run.


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RE: Old House Ground Wire

Actually, looking closer at what's under the sink, there is a small water line going through the floor in the cabinet and then coming back up on other side of kitchen to feed the ice maker. All I have to do is measure off that to drill the new hole. Below is a photo of my breaker. Can I feed the new romex through the existing conduit (or increase the size of the conduit if the conduit is already maxed out)?

How do I run the romex under the house, just staple it to the floor joists so it doesn't sag?


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RE: Old House Ground Wire

Sounds like you are trying to protect a multiwire circuit with a shared neutral. It is very common in kitchens, and with disposals and dishwashers. Are there any red wires involved?


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RE: Old House Ground Wire

No, no red wires. The ground wire is external in case you didn't see that above, and I'm guessing that the external ground runs all throughout the house across different circuits as you suspect.


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RE: Old House Ground Wire

The grounding wire connected to different circuits won't cause a problem, in fact the grounding conductors in a wiring system are required to be connected together at every splice, even those from different circuits. The neutral wires from different circuits are not to be connected together except at their origin.

In answer to your troubleshooting question, if you unplug the dishwasher and the GFCI does not trip that does not necessarily mean the dishwasher is causing the problem. Plug something else into the outlet, if something else plugged into that same outlet also trips the GFCI then the problem is in the wiring, either a G-N fault or a shared neutral.


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RE: Old House Ground Wire

Thanks joefixit2. Sorry, I misread "neutral" as "ground" in your first post. If I run a new circuit for the DW and GD, are there any potential problems with not being able to ground the circuit in my breaker? I haven't taken the cover off the breaker yet or know how things are grounded in a breaker to know any better.


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RE: Old House Ground Wire

rileyann,

I don't think Joefixit had read the original posts about the ground wire. The truth is that I don't fully trust that ground wire - that's part of the reason for making a home run to the breaker box.

If you don't feel comfortable making the connection in the breaker box, hire the whole job done. A professional will do a good job of getting it to the box, and getting it grounded properly. I think that running a new conduit (which is what would need to happen) may put the the job outside your current abilities.

Just so you know, current code requires at least two 20 amp small appliance circuits in the kitchen that feed almost nothing else (the fridge can be on one of those, a kitchen clock outlet and an outlet for a gas stove are all that's permitted to be included with counter-top outlets - no lights and certainly not GD and/or DW). There's a little more to the code than that... but you can google it.

I don't know if your remodel would obligate you to meet current code, but it's good to know what that code is. For sure if your counter-top outlets, GD, DW, and Fridge are all on the same circuit it needs the GD and DW split off. The circuit is over utilized even if there wasn't a rule about counter-top outlet circuits in the kitchen being kept separate.

The point is you need to make a home run back to the panel and you probably need to hire it done.


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RE: Old House Ground Wire

I'm on board with running a new 20 amp circuit but would like to run the wire between the outlet and the breaker myself, unless there's more to it than just stapling the wire to the floor joists. No conduit needed under the house, right? I would have a licensed pro run the conduit where the wire daylights to where it connects to the breaker. Does the DIY portion seem reasonable or is there more to it and better left to a pro?

Thanks,
R


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RE: Old House Ground Wire

rileyann,

I think you are parsing it too much... kinda like bringing your own food into a restaurant and asking them to prepare it.

An electrician is going to want to own the job from one end to the other. It's not a "profit" issue as much as they are going to want to be responsible for what was done from the breaker panel to the other endpoint. I'm a nice guy, but if you asked me to do what you are proposing I would absolutely politely decline -- and I think virtually any other contractor would do likewise.

You have saved money by doing much of the work yourself. You don't need to split hairs on this part of it.


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RE: Old House Ground Wire

JTWD, you are right on all accounts! Thanks for being the voice of reason here. I appreciate your input. I'll call the local pro and help stimulate the economy. This DW/GD issue was not on my radar but I always strive to do things right and for safety, especially when electricity is involved. I'll keep you posted. Check out my new outlet and rewire of illegal wiring out to my garage. Please critique. BTW, that external ground wire can be a pain to work with! Thanks again!


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RE: Old House Ground Wire

I understand the GD/DW wasn't on the radar - can completely appreciate that. And I'm not one who defaults to "let a pro do it". I do try to assess your skill / comfort level with a job.

Outlets look good. So, looks like you terminated the 2 wire with external ground at the first outlet and then ran 12/2 w ground to the downstream outlets. Is a good way to do it.

You should google "NEC for residential kitchen outlets" or some such. There are some good summaries of what the code is. Since you are doing this work, you should bring it up to code including number of outlets, circuits, etc.

Hey, just a tip that not everyone will agree with, but here it is anyway.... don't use the push in connections on the back of the outlet. Use the screws on the side. I've seen too many of the push-in connections fail.

Here is a link that might be useful: Summary of kitchen outlet code 2005


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RE: Old House Ground Wire

Thanks for the link. City inspection this week! I don't do the push in connections based on most of the opinions I've read online. I like using pigtails too, instead of running line/load through the device.


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RE: Old House Ground Wire

rileyann,

Let us know how the City inspection goes.
Good luck, but I'm sure you will be ok.


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RE: Old House Ground Wire

I meant to post sooner to say we passed rough electrical. All sealed up now. Thanks for all the help. I'll go bug the tile folks now! Still waiting on my electrician friend from high school to run the home run for my dedicated GD/DW.


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