BACKGROUND: Hi this is in Chicago so we use EMT Conduit as our grounding system and only use an EGC for stoves/dryers/sump pump/ etc... so I was working with my cousin to demo stuff in a basement in a residential Chicago home where only one 20 AMP CIRCUIT BREAKER with ONE circuit was provided by the "Electrician" which connected to 2 outlets in series 15 ft apart from each other. This circuit provided the service for tradesmen (i.e. charge power tools, use heavy duty masonry drills/ compressors/ microwaves/ heaters and Lights) to carry on their task. However, during the plumbing renovation one of the plumbers cut and removed the old plumbing copper pipes that were attached to the city's main water supply and left the remaining old copper pipes in the ceiling (idky they DID NOT remove the rest of the pipes. These copper pipes had a 12 gauge conductor attached to it to provide the "Grounding" factor. Now when the plumbers did this it led to voltage fluctuations to the point where i could NOT charge my cordless battery packs (18V ryobi and 18V bosch) and barely got any juice for my USB C phone charger. There was a pattern every second or half a second my equipment was able to get full charge but they would reset and i would hear a clicking sound, continuously.

PROBLEM: electrical service was fluctuating at an inoperable level.

-- We called "Electrician" and he took out his multi-meter and was getting different voltages from Neutral and Hot side about 120V HOT and 80-105V NEUTRAL or vice versa. He traced it back to the old plumbing where a white insulated cable was attached to the top/demo'ed part of the old copper plumbing system (which was still not removed at this point, which was a 2 day ordeal coordinating and communicating with "Electrician" and plumber. so he removed the white insulated wire from the old "Floating" plumbing system(which will eventually be removed) and connected it to the new copper plumbing system which went underground per-concrete poured.

SOLUTION: The "Electrician"said that he "Jerry-Rigged" a 12awg conductor from utility/gooseneck and connected it to the old plumbing system to use it as a grounding system. so when the old plumbing system was cut out from the earth, he simply attached the 12awg conductor to the new plumbing system in the earth and problem was fixed. Mind you the wire he "Jerry-rigged was connected to the NEUTRAL Conductor coming from the service lines outside above, bypassing the main panel, and being attached to the plumbing. The service panel's only circuit breaker had 2 conductors, 1 HOT and 1 NEUTRAL and the NEUTRAL Was grounded via the jerry-rigged conductor connected to the NEUTRAL Utility.

*Above was the scenario in chronological order of events.* 

My question to you Guru's is, Why on earth was the voltage fluctuating when the ground system was physically removed i.e. plumbing?

I thought Electrical circuits were not influenced by a grounding system and that the grounding system on affected voltage spikes i.e. lightning etc...

the circuit was still closed as our equipment was still charging (barely but still charging with a 25volt potential difference on N and H ends).

I know it had to do with the plumbing but once it was cut and just floating in the houses frame it would just be that, no loads or anything for it to energize im assuming....

Can you please break down why on earth was voltage fluctuating ?

  • Two important questions: 1 - so he removed the white insulated wire from the old "Floating" plumbing system(which will eventually be removed) and connected it to the new copper plumbing system Is this neutral (White is normally neutral, ground is green or bare) and where is the other end of the wire - panel or utility? Dec 21, 2020 at 18:01
  • 2 - the "Electrician" pointed out that the utility overhead neutral was broken so he jerry rigged it to bypass the broken portion and interfaced it to the house with a 12 or 10 awg - If this was actually the utility overhead neutral then using anything less than the appropriate size (which would be typically far larger than 10 AWG) is a major problem. Dec 21, 2020 at 18:03
  • Can you upload a picture showing the panel and all the wires going in/out of it? Dec 21, 2020 at 18:09
  • question 1 answer: YES that particular conductor is neutral. The other end of that conductor is jerry rigged to overhead utility. Dec 22, 2020 at 5:24

3 Answers 3


You have a totally different problem!

Your root problem is a lost neutral. Probably somewhere up on the service drop to the pole, the neutral wire has parted. Happens all the time; neutral is also the carrier wire that carries the weight of the other wires.

So you should check the panels for neutral integrity just in case it's something obvious. If you find nothing, it's probably the pole line - call the power company out and have them fix their wire.

Neutral is NOT dependent on any grounding. The power company supplies hot(s) and neutral from the transformer. That is all you need for power to work properly. An AC power system will work with no grounds at all if things are in order. The only reason we do anything with grounding is to increase occupant safety.

So what's the deal with this HUGE red herring??

Well, when you lose the neutral wire, neutral current can find an alternate route through the Grounding Electrode System. It's not a very good route since it involves traveling across dirt, but it's better than nothing and will provide some functionality. The route is:

The panel's neutral bar... via the main panel's Neutral-Ground Equipontential Bond ... to the Ground bar ... to the Grounding Electrode System (GES)... And I'm betting your neighborhood has metal water pipes... to the Grounding Electrode System of a neighbor... through their N-G Equipotential Bond.... to their neutral bar... to their wiring... back to the transformer.

This is a terrible state of affairs. You are not only moving current on your GES, which is a big no-no, but on your neighbor's grounding as well. Their neutral service wire is carrying not only their neutral current, but yours as well!

We don't ever want current moving on the grounding wires. Those are only for use during transient ground faults. Normal service currents must be all on the neutral, the wire intended for that.

Remember, the grounding systems are only an "optional" safety bolt-on; power will work without it.

Your power will not work without safety ground, which is how we recognize a Lost Neutral.

Barking up the wrong tree

Your "electrician" did not actually care about having a working neutral wire. Your electrician was trying to restore the original failure -- where neutral is out, but ground wires and water pipes carry your neutral current to your neighbor's. Shame on him!

Now, fix your neutral. Contact the power company and tell them power is out and have them fix their wires. This is done for free. And it takes an hour not a week.

  • I am 99% convinced this is not a utility problem, but rather a "stupid 'electrician' problem". Dec 21, 2020 at 15:39
  • HOLY Moly guacamoly....i talked to the "Electrician" and he paraphrased exactly what you wrote....he told me that we needed power asap and that utility was going to be about 2 weeks so he did some jerry rigging due to a broken utility neutral wire that he pointed out (Visible as day), he couldnt break down the theory like you did (Immaculately i might add) but he was able to troubleshoot effortlessly. Thats why he siphoned the neutral from utility before the broken portion overhead. Man you are AMAZIN' (JLP Phrase) Dec 21, 2020 at 17:47

With all due respect to Harper, I do not think this is a "traditional" Utility Lost Neutral - which would be a "Call the utility company ASAP" type of problem.

To clarify a little from what I said below:

Original Setup: Neutral connected VIA GROUND

Based on the description of the original setup, the plumbing changes, the resulting problem, *and the absolutely wrong "electrician" fix, I believe the original setup was:

  • Utility hot in conduit to panel hot.
  • Conduit grounded (bonded) somewhere/somehow to copper plumbing.
  • Utility neutral connected to copper plumbing.

This last item was a big code violation, because it meant that 100% of the neutral current (which for a single 120V circuit, means "everything being used") was flowing from the breaker neutral to the panel neutral/ground bond to the panel box itself, via conduit (the conduit itself, not a wire inside the conduit) to the plumbing, to the neutral.

This was likely a high resistance connection (because of the panel/conduit parts - steel does not conduct as well as copper or aluminum) but not high enough to make things stop working. In fact, most of the things being used - chargers, lights, power tools, could handle a drop from 120V to 110V without a noticeable problem. It was also potentially (pun intended) deadly because it means that some of the plumbing was electrified when any electricity was being used. Technically even the neighbor's plumbing, but realistically/practically, just the plumbing from the panel/conduit to the neutral connection.

Lost Neutral

Then some of the plumbing was removed. This broke the electrical connection between the panel (via conduit/plumbing) to the neutral (via plumbing). Now you had 120V (relative to neutral) coming in to the panel hot, but going out the electricity had no direct connection and went through the physical ground to get, eventually, back to the utility. This is a LOST NEUTRAL. Except not lost because of a utility problem, but rather because of two major errors combined: 1 - The neutral was connected using plumbing/conduit via ground bond in panel, instead of directly to the panel and 2 - part of that neutral......long path....panel connection was removed.

End result: "Neutral" at the panel/breaker would float. In theory anywhere between 0V and 240V, though I think in reality it would be anywhere between 0V and 120V. And it would actually float - not pick a specific lower-than-normal level (as it likely did when connected via the plumbing) but vary depending on how much current was in use and on anything that affected the panel->plumbing->earth connection (like people touching pipes!).

This was bad, and you knew it. So you called back the "electrician".

Restored BAD Neutral

Instead of doing the right thing - connecting the neutral directly to the panel, the electrician basically put things back the way they were originally. He moved the neutral to a different part of the plumbing so that it could again, indirectly, improperly and dangerously, connect to the panel to complete the circuit.

You are now back where you started. Perhaps slightly better, but not much and not truly fixed.


If I am correct, you have a lone hot wire running from the panel through conduit back to the service entrance/utility feed. Run a white wire through the exact same path. Connect it to the utility neutral (make sure you don't connect it to the other hot wire, which is likely sitting there waiting...). Disconnect the other white wire, as it should not be connected to actual (earth/plumbing) ground.

And if that is all the case, you can actually run a second hot as well and then be able to use the panel for additional circuits, including both additional 120V circuits and 240V circuits.


This "electrician" is clearly an amateur. And a not well-educated amateur at that. My guess is that he was hired by the owner to do a quick "get something running so the workers have power" setup prior to bringing in real electricians to wire up the building. That may have saved $100. But at serious risk to life and property.

What you are supposed to have is hot and neutral from utility to panel, ground from pipes /earth to panel, and in the panel neutral and ground connected together.

Instead you had hot to panel, ground to panel, and neutral to ground outside the panel. That was bad enough, but managed to work because 20A on copper pipes is doable (electrically, but not according to code or common sense).

When the plumbing was broken up, you lost the neutral and ended up with a floating neutral and your symptoms matched a floating neutral precisely.

Now you are back where you started. The problem is that you likely still have neutral running over pipe and or ground wire. That white wire should be extended with the hot wire directly to the panel. Hot and neutral should always run together as a pair (or triple with two hots and neutral). True "only fault current" ground can be separate.

  • There was NOT A ground cable (cable from plumbing to panel) inside the service panel. Again no bare copper ground wire from plumbing to panel. Also what do you mean in the 2nd paragraph, "20A on copper pipes is doable but NOT common sense ? ill take picture tommorrow for clarification Dec 21, 2020 at 6:13
  • Slight correction - you're right, because you are in Chicago = metal conduit, the ground is not a wire from the panel to "ground", but rather somewhere connection conduit to "ground". But the rest is the same. Dec 21, 2020 at 15:18
  • In this particular case Harper was correct because the "Electrician" pointed out that the utility overhead neutral was broken so he jerry rigged it to bypass the broken portion and interfaced it to the house with a 12 or 10 awg. Dec 21, 2020 at 17:48
  • Bypassed utility overhead neutral with a 10 or 12 AWG wire? WHAT???????????????? Dec 21, 2020 at 18:04
  • You mentioned earlier to post a picture, i will tomorrow so please standby. I am a curious and like to understand what every tradesmen do with respects to their science field. Dec 22, 2020 at 5:22

I believe you floated the neutral when the copper was removed and the utility neutral ground at the transformer may not have been good or properly bonded. If you had a live 120v line connected to the copper pipe it would have been shocking peopled or worse. With no neutral 120v devices would not have worked but 240 would have worked. This has been a common issue with older homes that only had water pipe grounding and the ground was removed with a plumbing update. With a device on 1 leg turned on and a different device on the other leg turned on you can see the wild voltage swings. With everything in conduit and a floated neutral with them bonded makes a return path possible on the conduit and what code calls an objectionable ground path (why 4 wire or 3 &pipe is required today). I have a training setup where I float the neutral to 2 light bulbs a 60w and a 100w on different legs and have the apprentice tell me what is wrong it really confuses them when they turn off one light and the other goes out and when they start making measurements the voltage swings, but this sounds like what happened to your system.

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