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Since a while, I've been having massive powerline spikes on both the Active and Neutral line. Spikes measured with my oscilloscope

It happens when I turn on a light (with a trafo attached to it), or have an ESD with my floormat, or when the hair dryer is turned on. The power lines that where used to take this snapshot of the surge, have a surge protector in front of them.

My A/V receiver turns off for a second or two regularly, to protect itself from the spikes (I guess)

The only thing that recently changed was our Energy Meter. The wires have been there for around 20 years and we've never had problems with it. On every socket Earthing is available, and used.

What is the cause of this problem and most importantly, where do I get started to solve it?

EDIT:

The energy meter was checked by a electrician and it was properly installed in the first place.

2nd edit:

I noticed something strange, and I'm not really sure if this is supposed to happen.

Active and Neutral

The pink line is the neutral line and the yellow line is the active line. Is it normal for the neutral to 'follow' the active line a bit?

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tim687
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  • Where is the problem? Does your hairdryer malfunction and burn you? – Andy aka Mar 27 '20 at 11:56
  • That all some of my appliances, like my A/V Receiver and my television black out for a second randomly (well when such a spike occurs). – tim687 Mar 27 '20 at 12:01
  • There may be a loose connection in the incoming mains. – vu2nan Mar 27 '20 at 13:14
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    Your post doesn't explain the measurement method or scope connections. – Transistor Mar 27 '20 at 13:28
  • _"My A/V receiver turns off for a second or two regularly, to protect itself from the spikes (I guess)"_ Highly unlikely. It sounds more like EMI causing a reset. – winny Apr 08 '20 at 11:10
  • @winny, could that reset be so short that the device turns back on within a few seconds? Does grounding the device, fix the issue? – tim687 Apr 09 '20 at 07:31
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    Definitely. It may, but difficult to say for sure. If you are even a little bit uncertain around a multimeter and mains electricity, you'll have to trust your electrician, but I would measure ground continuity and ground to neutral voltage if I were you if you are certain the problems came after changing the energy meter. – winny Apr 09 '20 at 08:15
  • @winny, found it! Most outlets have a resistance of 0.0 Ohms from Neutral to Ground, but there are a few that have a resistance of 34M Ohms from Neutral to Ground. I suppose this is a problem inside my fuse boxes? Or can I fit it myself. The main grounding connections are exposed in the electricity cabinet – tim687 Apr 09 '20 at 08:43
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    Bingo! Time to call an electrician and/or tell the guy who installed the new meter to fix what he/she broke. – winny Apr 09 '20 at 08:52
  • @winny You don't recommend fixing it yourself? ;-P Thanks for your help and advises! – tim687 Apr 09 '20 at 09:06
  • I don't know your skill level so I don't want your death of my conscience. I would not hesitate to fix it myself. You are most welcome! Stay safe! – winny Apr 09 '20 at 09:13
  • @winny I opened up the fusebox, tightened some power line screws and most importantly a few loser earthing screws. It improved the resistance on some lines a lot, but the problem is not over yet. I am running 12V AC led lighting with a old 230V AC -> 12V AC transformer, could that cause any problems? – tim687 Apr 12 '20 at 08:40
  • Highly unlikely. Loose earth screws is grounds for disciplinary action against the electrician in some countries. – winny Apr 12 '20 at 09:24
  • @winny So what else could it be? A bad device connected to mains? A cheap (chinese) power supply? A defective PC power supply? – tim687 Apr 12 '20 at 09:47
  • Both, but how’s ground continuity? – winny Apr 12 '20 at 10:36
  • You mean from an outlet to grounding point in the fusebox? That is fine! Around 1 Ohms at max. In some sockets, the resistance from Neutral to Earth is still around 34 M Ohms – tim687 Apr 12 '20 at 14:24
  • @winny how would I continue now? Check every socket and try to find a correlation between the sockets wiring origins to check for mains wiring faults in the walls? – tim687 Apr 13 '20 at 21:01
  • That’s exactly it! You should become an engineer! – winny Apr 14 '20 at 06:53
  • @winny After a couple of hours, I observed the following; the Neutral to Earth resistance on the same group is about the same (0 Ohms). But suddenly the N->E resistance rises to a range of 5k Ohms to 40M Ohms and fluctuates a lot (I seriously mean a lot, a few kilo ohms per second). It's like a device that is not permanently on, switches on/off like a boiler. Unplugged them all, didn't make a difference. I measured the continuity of L, N and E lines of the same group and there was one N line that was randomly flickering between 0 and 2 Ohms, is that bad? Earthing to the earth is fine. – tim687 Apr 14 '20 at 12:36
  • When/were is suddenly? Any appliance with ground, probably water heater, solve or oven can leak resistible to ground (many kohms (100 uA)) and pretty much any SMPS will have a 470 pF-1 nF capacitor from N and L to ground. You will only see the effect of that if there is a break in your earth connection somewhere. – winny Apr 14 '20 at 16:51
  • @winny the sudden increase is on a different group than the heater, oven and other heavy power appliances. I forgot to mention, when I accidentally tripped the earth breaker (GMC breaker, I think it's called), the groups that are connected to that breaker, got triggered when I activated the GMC breaker, now there are a lot of devices on that group, switches computers and routers to it might be the in rush current, but I still find it strange. – tim687 Apr 14 '20 at 21:20
  • @winny I've found somebody with exactly the same problem as I am having! https://superuser.com/questions/1406140/monitor-screen-that-blanks-due-to-static-electricity-in-my-chair I rewired some of the busses and cleaned up the wires going into them. Some of them where a bit black spotted on the copper ends – tim687 Apr 25 '20 at 22:45
  • Tripping your RCB sounds normal if you measure it live. Black spotted on the copper ends does not sound good. Did you find a break somewhere? – winny Apr 26 '20 at 08:15
  • @winny I did not, the resistance from Neutral to Neutral did improve drastically! No more fluctuations and the resistance from N to E was so 0 Ohms. Still need to do the second group, but I'm worried that those junctions are inside the walls and not inside a juction above a lamp (as was the case with group 1) – tim687 Apr 26 '20 at 10:20
  • @winny Is the neutral wire supposed to follow the active wire a bit? (I've updated the question with a screenshot) – tim687 May 06 '20 at 07:39
  • Are both L and N measured with respect to local ground? Does it change with increased/decreased load in your house? – winny May 06 '20 at 09:41
  • @winny, I found a few comments on the internet that immediately caught my attention. Measure from the hot lead to that ground lead If you get full voltage, then it's a neutral failure. (https://forum.allaboutcircuits.com/threads/locating-loose-neutrals.157644/post-1366566) The lights would occasionally flash or dim along with something else (heat circulate pump, clothes of dish washer) turn on or off. : (https://forum.allaboutcircuits.com/threads/locating-the-suspected-loose-neutral-problem.119155/post-944507) Guess the voltage from Live to Earth. We've got the same dimming issue – tim687 May 06 '20 at 10:55
  • No, that depends on what country you live in and in some cases also what region of said country. I would suspect you have a "normal" TN-C-S configuration as shown here: https://en.wikipedia.org/wiki/Earthing_system#Types_of_TN_networks – winny May 06 '20 at 11:17
  • @winny that is correct! Could you list the expected values when measuring resistance , and voltage between N and E, L and E, L and N? At this point I'm not really sure what to look for anymore. My suspicion is still on a loose neutral wire since the dimming issue has been there for at least 20 years and spikes still get on neutral the line when an ESD occurs. – tim687 May 06 '20 at 11:39
  • Wish I had a fixed value to give to you. 1.35 V does not sound unresonable. You can estimate the load, assume 1.5 mm^2 wire and some length in your building and calculate the resistive drop and compare. Your sinusodial phase does look unusually flat at the top and you can see the "crosstalk" from the two other phases so I assume your house/residential area is served by three phase (i.e. outside of North America). – winny May 06 '20 at 11:48
  • Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/107679/discussion-between-tim687-and-winny). – tim687 May 06 '20 at 11:50
  • Sorry, the chat room expired. The log by the power company was nice, but it was aimed at finding slow variations, not loose neutral or very intermittent problems. Do you have anything between the utility company’s box and any fuse central in your home? – winny Aug 22 '20 at 19:50
  • Sorry for the late reply, their energymeter (with wires obviously) is in between. From what I can remember, everytime they tighten the screw terminals, the problem goes away for a while. But that might be Murphy's Law :-P The issue hasn't gone away/got better/got worse in the meantime. – tim687 Oct 05 '20 at 09:53

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I would log a request with the utility to redo the tightness check on the electricity meter connecting screws. Tell them you have surges on the power line that black out your equipment when you turn on your 12 V lamps after they have installed the electricity meter.

You can also ask an electrician to do an earth continuity check on your plug circuits.

skvery
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  • Do you think that there might be a problem with the energy meter? I will contact my energy supplier to check if they have somebody around to fix it! – tim687 Mar 29 '20 at 10:04
  • As I said, most likely a loose connection when they changed it. – skvery Mar 29 '20 at 10:06
  • I was suspecting this already, but since I'm not that advanced in electronics and especially AC I wasn't sure. – tim687 Mar 29 '20 at 20:04
  • The net manager came and the energy meter was properly installed in the first place. The issue is still here. – tim687 Apr 08 '20 at 10:39