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When turning on high amp appliances like an air compressor or dust fan, the attachment of the ground from the meter box to the water main (pic) sparks occasionally for a second or so. A separate ground from the meter box was also installed a few years ago by an electrician that runs directly to a ground rod outside.

Is this normal discharge, or does it indicate an underlying issue? If it's normal, should I insulate around the ground to avoid a shock?

ground connection

Edit: Ground shows current with certain breakers on. Note: There are two grounds coming from the main box. Only one has current. meter on ground

Update: We're not electrocuted (yet).

POCO came onsite and discovered poorly connected neutral at the city pole byt runnign a load test at the main drop. He reattached it, and the baseline amperage on the ground dropped from 6A to ~.6A immediately. 10x reduction, but still present. Current is now detectable on both the water main and ground rods instead of just the water main.

If I fire up all the power tools, vacuums and heaters at my disposal, I can still measure up to 3A on the ground. This isn't associates with load on any given circuit. It returns to under 1A if I turn off the main and eventually baselines at ~.1 whether or not the breakers are on.

POCO says this is not an issue, but the consensus here and during a 5 min phone call with an electrician says otherwise. Electricians are booked several weeks out unless we pay emergency rates at $770 + 300/hr. Electrician also said all he'd do at this point is repro my circuit by circuit test.

On an editorial note: Thanks to everyone for the suggestions and concern for our safety. DIY has its limits.

Laramie
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    That is not normal at all. – Jon Custer Jun 11 '22 at 18:01
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    When you have sparks with electrical devices/connections it is due to the connection being loose, or bad due to dirt/corrosion. The fix most of the time is to clean the connection and tighten. Problem is you have sparks on a ground connection, which should only have power/electricity when there is a major problem somewhere else in the system. – crip659 Jun 11 '22 at 18:07
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    Looked at the picture with it zoomed out some. The marks from the sparks look to like they are powerful sparks(like welding). Would get an electrician there yesterday. – crip659 Jun 11 '22 at 18:23
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    call an electrician right away ... if the electrician tightens the ground connection at the pipe and does not do anything else, then he/she does not know what they are doing – jsotola Jun 11 '22 at 18:23
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    1- there should be no power on the grounding wire, ever. 2- Even if there is life threatening fault in your wires somewhere in your home, There should be no Arching at ground connector. That conetion is flimsy. The pipe is coroded. – Ruskes Jun 11 '22 at 19:14
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    WOW, 6 amps via a ground. WAAAAYYYYY to much. Until you get the POCO out there, don't hold onto the oven range and a faucet at the same time! Dang, this is a dangerous situation. – George Anderson Jun 12 '22 at 03:27
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    OP, once you get this addressed, please update your question, mostly so we find out the exact cause but also so we know you didn't die by electrocution/house fire. – Michael Lorton Jun 12 '22 at 17:27
  • For the safety of you and your family, please move out of this house until this has been fixed by an electrician. Make sure your will is up to date. – Dawood ibn Kareem Jun 12 '22 at 23:41
  • BTW (once this is fixed) looks like the other clamp came off the pipe somehow – user253751 Jun 13 '22 at 09:08
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    Water pipe in 1st photo looks like it has an eroded pit near the upper clamp maybe from the arcing. The pipe may now be in danger of bursting there, so once you get the electrical situation fixed, have a plumber replace at least that section of pipe. – Armand Jun 13 '22 at 19:43
  • update above. TLDR: Neutral was marginal as predicted but some current remains on ground. – Laramie Jun 14 '22 at 00:55
  • This has nothing to do with DIY. You used DIY to identify and diagnose a problem that allowed you to know to call the power utility, who identified a problem with _their_ equipment. A licensed electrician would also have to call the utility and would not be able to solve the problem without them. So nothing to do with DIY. – RibaldEddie Jun 14 '22 at 18:06
  • As to the current still flowing on the ground wire after the visit by the utility, you've already started down the path of finding the problem. You could use the tools you've got (like clamp meter) to hunt down which circuit is energizing ground. Once you've found that, you'll either find a malfunctioning appliance or an outlet or fixture that has likely been improperly wired. Again, the same thing an electrician would do. – RibaldEddie Jun 14 '22 at 18:08
  • It also sounds like you might have a problem with equipotentiality. What that means is that your ground is acting like a parallel neutral. The return current for the split phase can return to ground via the neutral OR via the grounding conductor. – RibaldEddie Jun 14 '22 at 18:15
  • I would concur that the earth-based return path for the poster is lower than is typical. 6A is a lot of current to have flowing through the earth, and would mean the effective earth return path resistance must be under 20 ohms, and that is assuming the load had literally zero resistance. I'm pretty sure many residences would have much higher earth based return path resistance than that. After all 25 ohms to earth at the rod location is often the target, and that does not include the resistance of the earth between the utilities grounding rod and the customers rod. – Kevin Cathcart Jun 14 '22 at 19:04
  • My guess would be the earth based return path could be single digit ohms here, and that would suggest greater parallel return current through the ground than would normally be expected., so it might simply not be possible to get ground rod current as low as it would normally be. But if it were my house I'd still want to investigate quite a bit more, just to ensure no weak neutral or other faults remain. – Kevin Cathcart Jun 14 '22 at 19:06
  • Glad we could help. open neutrals send anyone here who is an electrical expert into apoplexy because they are truly dangerous. A small amount, like less than one amp going thru ground probably isn't big deal. As long as the voltage isn't much more than a couple of volts between neutral and ground, it's probably nothing to worry about. Admittedly it would be hard to measure. You'd have to stick a long length of bare wire in the ground and then measure the voltage between it and the neutral/ground in your panel. – George Anderson Jun 15 '22 at 02:28

2 Answers2

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You lost neutral! This is an outage and an emergency

Your neutral wire no longer connects back to the utility. Out of desperation, neutral is pathing through your neutral-ground equipotential bond, the ground rod and the dirt... to somebody else's ground rod and their N-G bond and neutral. Dirt is a terrible conductor, so this results in crazy voltages.

USUALLY this is the power company's service drop to your house. That is two insulated aluminum wires hung off a bare aluminum carrier wire, which is anchored at both ends. This is both neutral and carrier, and if whips in the wind. Aluminum has no fatigue limit. So the wire snaps!

Often you can walk outside and look at the power company service drop wires and see if the carrier wire appears to be poorly attached or broken. Check both ends.

This wire is the power company's responsibility, and they will repair it fast for free, since it is a legitimate power outage.

What is happening is that without a neutral, nothing keeps 120V at 120V anymore. Now your hot wires are still 240V apart, but your two banks of 120V are drifting all over the place (yet adding up to 240V). This can be hard to detect, but it can also fry your appliances.

If this is at an outbuilding with a subpanel, check your house; if wired old-school (3-wire), then the problem is the subpanel feeder.

You can test this by checking voltages all over the house. A lost neutral is indicated by two groups of near voltages, one group under 120V and the other over by same amount but totaling to 240V-ish (e.g. 105 and 137). If you power up a high-power 120V appliance, this voltage difference changes (e.g. 81 and 160).

Footnote: It is possible that the current on your grounding electrode isn't caused by your own lost neutral, but rather, your neighbor's. However, I doubt that because you switching on large 120V loads has direct effect on the symptom. That wouldn't be so if your neutral was OK.

Harper - Reinstate Monica
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  • Yeah, sounds like an open neutral to me as well. Very dangerous. UV to your answer. – George Anderson Jun 12 '22 at 00:36
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    I turned off all the breakers and measured (correctly this time) the ground (updated pic above). As predicted, there is current. The city drop appears intact. No visible separation but difficult to verify. There is a subpanel, but I turned off the breaker for that as well when I checked the ground current. Does this rule out something inside the house? Should I call the city ASAP or wait for an electrician Monday? And thank you! – Laramie Jun 12 '22 at 02:37
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    You should ***not*** wait. If you have to wait, turn off electricity. – vidarlo Jun 12 '22 at 14:25
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    @Laramie Current flowing on ground wire even when all breakers are off could indicate that also neighbor houses have lost neutral, or that there is some load that is not behind the breakers. In any case, I would let the professionals figure the details out, as the situation is very dangerous to go poking around. – jpa Jun 12 '22 at 17:03
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    @jpa That's a very good comment. I was thinking: "How the H.E. double hockey sticks could there still be current on ground with all the breakers turned off. But you are saying it's back flowing from other people connected to the same transformer, yikes! The OP's panel was also probably "borrowing" their ground path at times. Very good call jpa, I wouldn't have thought of that . – George Anderson Jun 12 '22 at 20:12
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    Two huge dangers here, Like you said Harp, those voltages could vary all over the place...put a large load on one leg and the other leg spikes while the loaded leg suffers voltage drop, both can damage devices/appliances. The OP should leave all breakers off and be very careful around grounded appliances, esp. in kitchens and bathrooms. once again: YIKES – George Anderson Jun 12 '22 at 20:16
  • @jpa correcting earlier statements on current with the breakers off. Can't repro it. Current returns when certain breakers are on but otherwise it's zero. We're laying low, ordering out and calling the electrician in the morning. We had a construction crew coming in the morning. Calling them off. Ugh. – Laramie Jun 13 '22 at 02:13
  • Thought here--maybe **he** didn't lose neutral, maybe it's upstream of his house. – Loren Pechtel Jun 13 '22 at 05:21
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    @Loren I entertained that thought, but then OP can control it by switching appliances on/off. – Harper - Reinstate Monica Jun 13 '22 at 06:06
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    Harper - Reinstate Neutral – user253751 Jun 13 '22 at 09:06
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If you see sparks at a ground rod, you have serious problems.

Could very well be a lose or weak neutral and a lot of current is returning to the transformer via the ground rod(s). The more I think about it, you almost certainly have a very weak neutral or completely open neutral both of which are dangerous.

Think about how grounding conductors are connected to devices, both plug in and hard wired. If you lose the neutral, the frames of appliances are now energized (i.e. not at ground potential). This is Very dangerous, esp. in bathrooms and kitchens.

A grounding electrode system is not intended to carry any current other than when a defective appliance or device is connected. If you have (or could buy) a digital multi meter with an amp clamp, put it around the wire going to the ground rod. If there is any current more than a small amount of current there (more than 0.1 amp or so), you most likely have an open or weak main neutral.

James Risner
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George Anderson
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  • Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/137048/discussion-on-answer-by-george-anderson-the-main-ground-on-my-house-sparks-when). – BMitch Jun 13 '22 at 13:43