PZEM016 voltage sensor outputting 250v DC into mains power

[crossway]

Hello everyone. I use a PZEM016 to measure my home power consumption. It all worked fine until yesterday. I was chaning a power outlet, so I turned off the circuit breaker related to that specific outlet, not to find out when I grabbed the neutral that I received a shock. Measuring between earth and neutral I found a little surprise 250v DC, or 130v AC (my meter keeps going from 60v to OL while measuring ac)
I started to search the culprint and I figured it was the PZEM releasing this voltage into the neutral of the entire house.
So... I never noticed this, do you think it is "normal" for the pzem to do such thing? Or is it failed?

[jorank]

If you get a shock when you touched neutral and ground, your earth is probably connected to a phase because of a broken device. You probably have a broken or missing important electrical component. Also, if this happens for a long time, your ground is probably broken or weak, and you maybe have to remake the ground.

[DVDdoug]

Here in the U.S., neutral is supposed to be connected to earth ground at the breaker box.

If everything is wired correctly you can only get about a 1V difference between earth & neutral when current flows through the resistance of the neutral wire.

so I turned off the circuit breaker related to that specific outlet, not to find out when I grabbed the neutral that I received a shock

Are you sure you turned-off the right breaker?

I saw a photo of something once that was sort-of a joke. It was a switch mounted in an electrical box with a plug. You plug it in and throw the switch and it shorts-out the outlet, blowing the breaker!

[TomGeorge]

Hi,
You should not have any voltage AC or DC between neutral and earth.

Get your switch board checked, possibly you have an open circuit earth, especially if the power part of the outlet works on mains powered loads.

Do you have a mains socket tester?
https://www.bunnings.com.au/deta-power-outlet-tester-plug_p4420488

What part of the world are you in?

Thanks... Tom...

[crossway]

@jorank

your earth is probably connected to a phase because of a broken device

If this was the case the circuit breaker would trip even before the RCBO since the neutral is shorted to earth in a TT system (like the common italian ones)

@DVDdoug

Here in the U.S., neutral is supposed to be connected to earth ground at the breaker box.

In Italy it's the same, except that the neutral is connected to earth inside the grid distribution center.

@DVDdoug

Are you sure you turned-off the right breaker?

Yes. It's turned off. No voltage between L & N. Just this "ghost" DC voltage that disappears when I disconnect the PZEM from the wall.

@TomGeorge

Get your switch board checked, possibly you have an open circuit earth, especially if the power part of the outlet works on mains powered loads.

This is fine. Earth is connected and working as expected. (It's checked yearly by a company that is called to check the functionality of the whole building earth system)

@TomGeorge

What part of the world are you in?

Italy. TT system is the one used in residential locations here.

Actually here's what I thought as of now. The PZEM could be wrongefully connected to the Phase of the correct breaker and the neutral of the wrong breaker (the one that is controlling this outlet). This could explain why there is this issue, since my breakers are 1P+N type.
I'll look into this tomorrow. But my question persists, how come the PZEM is releasing this voltage, is this an expected behaviour?

[jorank]

Shorting ground and earth together is a very bad idea and it's quite dangerous. If you find a system in this status, you may have to disconnect they and remake the ground.

[crossway]

This is not something I did myself, I belive it's the system used in whole italy's grid network, I could be wrong. If you want to do some research it's called TT system for residentials and TN for industrials.

[MaximoEsfuerzo]

It's not cutting the live (L), it's just cutting the neutral (N).
The live (L) circulates through the sensor, that is why there is voltage between neutral (N) and ground.

If I'm right you must have tension between live (L) and ground.

English is not my native language and I don't know if Google does the correct translation. Sorry.

[johnerrington]

@crossway

Italy. TT system is the one used in residential locations here.

You will need to show us how the PZEM016 is connected.

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

My best guess is that you have a fault on a ring main.

[crossway]

@crossway

Actually here's what I thought as of now. The PZEM could be wrongefully connected to the Phase of the correct breaker and the neutral of the wrong breaker (the one that is controlling this outlet). This could explain why there is this issue, since my breakers are 1P+N type.
I'll look into this tomorrow. But my question persists, how come the PZEM is releasing this voltage, is this an expected behaviour?

Actually I was right. The PZEM was connected to the phase of the correct breaker, but the neutral was connected to another circuit, and I guess the fact that it was still working in this configuration, with the neutral breaker off is thanks to the TT system.