Why is my voltage dropping with load and why is current flowing on my ground wire?

Question

I am not an electrician, but I've been researching a lot recently to try and figure out why my system is behaving so strangely.

Main problem: Lights flickering, sometimes quite severely, and appliances sometimes just turning themselves off or not working properly (e.g. microwave seemingly working but not generating much heat). Last night, for example, my AppleTV turned itself off multiple times while watching a one hour show.

More Info: I have two meters, which feed into two panels that are next to each other, one for the basement, and one for the 2nd floor. The 2nd floor panel feeds into a sub-panel next to it which is for the 1st floor.

I bought some electric meters and testers and have found some distressing things. With a Kill-A-Watt style plug-in meter, I've found that the voltages in my house are often not great. If I try to turn off everything in the house, the voltage everywhere is generally around 120V +- 3V. However, if I put a significant load on (like a space heater or bathroom fan heater), the voltage in half the outlets in the house goes down to around 95V while the other half of the outlets go to 135V. These voltages are not just a transitory spike, they persist as long as I keep the load on. And this is not a enormous, unreasonable load I'm putting on; my space heater that I have been using to make the voltage drop to 95V draws something like 9 amps. I also find that if I pile on more load, I can get one side as low as 75V while the other side goes up to 145V persistently.

I mapped all my lights, outlets, and appliances to their circuit breakers, and I found that all the outlets that go down in voltage together are on one leg of my service, whereas all the outlets that go up are on the other leg of my service. The leg that goes down in voltage is the one where I put the extra load, and I can change which leg goes down and which one goes up in voltage by plugging my space heater into outlets of different legs. The lights that flicker or dim are always on the service leg that has low voltage.

The other interesting thing is that I used a clamp meter on my ground wires from the panel, and I found a significant amount of current flowing through the ground wires between the panels and out to the water main. If I put the space heater in the basement, for example, I can get as much as 5 amps flowing on the ground wires out to the water main, and the clamp meter shows that 5 amps is flowing on the pipe itself out to the outside world. I'm far from an expert, but this concerns me.

I also bought an outlet tester, and I tested almost all the outlets in my house (There are four I didn't test because I didn't want to invade my houseguests' privacy in their bedroom). All but two outlets tested fine, and those two showed reversed hot/neutral.

Several electricians have come in and worked on the system. Each have found real problems and fixed them, and things sometimes get better for a while, but often return. The power company came months ago and found the neutral wire basically totally disconnected in the power feed and the meters. An electrician tightened up a bunch of neutral wires in the panel. Later, he installed the ground system to the water main (there was no connection to the water main before). Another electrican just this week disconnected the ground from the neutral in the sub-panel.

I have another electrician coming in to diagnose and work on the problem tomorrow, but I'm curious if anyone has good ideas as to what might be causing this problem and/or what sorts of tests I should be doing to narrow down the culprit. Thanks!

UPDATE: A power company worker came out and opened up the service box where my meters are connected to the outside. He found that while both hot wires had current flowing, there were exactly 0 amps on my neutral. He undid the neutral connection and replaced it but the neutral still read 0 amps. He agrees the problem is on their side somewhere. Now he's sitting in his van watching TV on his phone while he waits for something. I'm not sure what.

FINAL UPDATE: It took about 4+ hours, but they got it fixed, and I have rock solid 120v no matter what load I put on the house. I'm over the moon. They ended up bringing in a tanker truck with a giant vacuum and pressure washing out the maintenance hole, which was literally completely full of gunk. Eventually they uncovered the wires underneath the muck, connected the neutral, and it's all fantastic. Thanks so much to folks here, especially @Harper - Reinstate Monica, who gave a phenomenal response that was very helpful.

Answer 1

Turn off 120V appliances NOW. Call the power company and report an outage.

What you have is a classical "Lost Neutral". The dead giveaway is when circuits teeter-totter: when one pole's voltage goes down and the other one's goes up.

This is the most dangerous type of power outage. If you lose a hot wire, half your circuits go dead until a 240V appliance tries to power up and then the dead half comes back at low voltage. Not so bad. But This failure results in some appliances seeing well over 120V, and that can cause appliance burnouts and even start a fire.

95% of the time, the problem is at the power company's service drop from the pole; since that's outside swinging in the wind. So just call them. Report an outage, specifically high and low voltage at your panel main (which you know since it affects many circuits). I wouldn't mention "lost neutral" to the operator as they will sometimes try to talk you out of it, but definitely say it to the lineman!

Meet the lineman and be their "gofer", as the lineman may need you to warn neighbors and/or shut off neighbor main breakers. Being there for that will make the repair go much faster, since the lineman can stay up in the bucket.

Last year my complex lost a neutral. It took almost a week for anyone to detect it; I got wind when my partner said "I'm sorry these waffles are taking so long, the toaster is really slow.” I flew out the door, got a DVM, measured 95V, went in the storeroom (on my neighbor's leg), measured 145V, and called the power company. They said "I'm sorry, we can't come now, we're helping the fire department fight a tree fire. We'll be there in an hour". This was a Sunday. They not only fixed our complex's neutral, but a neighbor's hot that was failing. The neighbor was "living with it", as did all the other occupants of my complex for a week.

About current flow on your safety ground

Your house is trying to return neutral current any which way it can. One way it's trying is through the earth. It's flowing current via your neutral-ground bond to your grounding electrode system, through the dirt, to the transformer's and your neighbors' ground rods. Not a good thing!

Its status, as an extended and protracted problem

The difficulties you've been having are nothing short of insane. I find it inexcusable that a revolving door of professionals cannot fix a reproducible problem like this. It affects both panels, as you say, therefore nobody should be looking at anything that isn't common to both meters. Nothing downline of any meter need to be evaluated, since 1 defect is affecting 2 meters. This is a mind-boggling failure of diagnosis on several people's parts.

It's been a common refrain this week, of people having obvious systemic problems and yet spending thousands of dollars paying electricians to replace individual receptacles and switches. Clearly either the "electrician" has no idea what to do, or is powerless to fix the problem, so does something. This is called "rearranging deck chairs on the Titanic" or "fiddling while Rome burns".

My strongest advice is to turn everything off, and set up test conditions that are effortlessly confirmed: energize 1 circuit on each meter, both on the same pole/leg, and put 1 heater on each, to provoke the problem. Then tell the lineman "Here it is, failing. Make this go away, or open up the meter box and show me where 120V is balanced on my side of both meters, yet imbalanced at my main breaker." Don't let the lineman leave until it's done! And don't let the lineman shut the main breaker off, because that will hide the problem.

This type of repair is very definitive. When it's fixed, it's fixed.

The power company came months ago and found the neutral wire basically totally disconnected in the power feed and the meters.

That sounds like it is exactly the problem. Did they fix that?

Another electrician installed the ground system to the water main (there was no connection to the water main before).

You're kidding me. Obviously your grounding electrode system works, since the house has been returning current on the grounding electrode this whole time. This work was redundant! Better grounding is generally better, but improving grounding to avoid fixing a fault condition is negligent and dangerous.

Another electrican just this week disconnected the ground from the neutral in the sub-panel.

Subpanels must have grounds and neutrals separate regardless, and it's right to do, but it's more rearranging deck chairs and ignoring the core problem.

Funnel them to the core problem

As I said, I'd set it up to induce the problem. Then, pull the cover off both main breakers coming off both meters and measure from neutral to each of the hots, on the supply (unswitched) side of the mains. If both meters and main breakers have this same problem (with the same voltages given static loads), then the problem is before this point - it is between here and the pole transformer. Absolutely forbid anyone to work anywhere after that point. I would wrap the panels in saran wrap and say "We are not touching any of this today. Here is the problem; fix this only".

Now, a small part of this area is in your bailiwick to fix. However most of it is in the power company's bailiwick. Is it possible they've been telling you to fix something and you've just been ignoring them (don't imagine so, but just checking).

Answer 2

With your voltages varying that much from one leg to the next, you definitely have a loose/open neutral somewhere. That would also explain the current draw on the ground wire. If the problem exists on all your meters you might need to call the power company back to recheck their neutral connections. If the problem exists on only meter, then recheck the neutral connections in that meter can. Open neutrals are dangerous so I'm glad you're taking them seriously and getting the right professionals involved.

Answer 3

This is a potentially-deadly "open neutral" issue because it can create to dangerously high voltages on the OUTSIDE of appliances. I found mine with one hand in the sink and another touching the microwave.

Answer 4

I have read through some of these comments and I have to laugh. Do you realize that with this advice that some of you give could have you in legal jeopardy. This was an open/loose neutral condition. On POCO's end to boot. An open neutral is just as deadly if not more than plugging a radio in and setting on the bath tub while you bathe. There is only one way to determine if the loose neutral is at the POCO's point of termination or elsewhere. You would have to open the meter pan and check it right at the head of the source. The only advice that should have been given was to call a qualified electrician. There is certain PPE that is required before opening energized equipment. I am quite sure the home owner doesnt posses this. Or any home owner. Unless you are in the trade. The moral of thus story? Don't get dead. Call a qualified electrician.