Ground Arduino / Ground 220V

I would like to use a INPUT_PULLUP digital input from my Arduino using my existing home wires.

If I connect Ground wire of 220V to my Arduino GND and I set GND signal using Ground wire of 220V, will I burn my arduino card or it will work??

In theory there is no tension there, but I do not know if AC noises will destroy the board (or chip).

Thanks.

If I connect Ground wire of 220V

220vac doesn't have GND. It has LINE and NEUTRAL.

The EARTH GND is not part of the 220vac. It is part of the transformer safety wiring to prevent electrocution. The EARTH GND is not required to deliver 220vac. It is MANDATORY by National Electrical Code (NEC) for the safety of homeowners. The GND wire has NOTHING to do with the 220vac. It is connected to the Neutral to keep the Neutral at GROUND potential so if a wire comes loose inside some equipment and touches the metal chassis of the equipment, the chassis (which is required to have an EARTH GND ) will immediately short the 220vac to GND and blow the fuse or breaker , preventing the metal enclosure from conducting lethal voltages to an unsuspecting homeowner.

You obviously do not have enough experience to be messing with mains voltage and should not touch it or mess around with it at all.

Mains protective earth is not signal ground. What are you trying to do?

Do you mean PE/Protective earth/earth when you talk about 220V ground?

Connecting PE to Arduino GND is fine as long as the power supply you use is okay with that. A PC is. Better still, if your Arduino is connected to a desktop PC then Arduino GND is already connected to PE.

But then you want to make a switch between an Arduino pin and the PE wiring in your house? In theory that's fine. But it sounds like it's going to take some wire, like a couple of meters. If you are planning on doing so I would not just use the internal pull up but use a stronger external pull up (like 1k). I would also add a protective series resistor (like 100k).

So you have

                            |
                        1k pull up
                            |
Arduino pin - 100k resistor - switch to GND

would like to use a INPUT_PULLUP digital input from my Arduino using my existing home wires.

If I connect Ground wire of 220V to my Arduino GND and I set GND signal using Ground wire of 220V, will I burn my arduino card or it will work??

It sounds like OP wants to use his mains wiring send a signal to or from his arduino.

I do not want to use ground cable from 220V, I wanted to use Neutral one. (Sorry, I wrote it wrong)

Usually colors in 220V are: yellow-green for GND, Black for Neutral and Brown for Line.

To keep Andruino and Neutral to the same voltage, I was saying to connect Black and GND form Andruino.

As Raschemmel says, the idea is to use main Neutral wiring to send to set 0V to INPUT_PULLUP.

septillion: So you have

                           |
                        1k pull up
                            |
Arduino pin - 100k resistor - switch to GND

Thanks Septillion, following your schema, result would be:

          +5V  
            |
      1k pull up
            |
Arduino pin - 100k resistor - switch to GND & Neutral 220V Line

And  Neutral Line 220V Line & GND from Andruino always connected.

Right?

To keep Andruino and Neutral to the same voltage, I was saying to connect Black and GND form Andruino.

Don't do that. You must not connect the nutral to the Arduino ground. 1) From a safety point of view, legally live and nutral must be considered to be interchangeable. 2) There is a voltage between nutral and Ground of about five volts. Connecting them together should trip the residual current breaker in your house but not all houses are fitted with one. 3) Why do you want to do this? What are you trying to do? Are you trying to kill some one?

Hi, What is your project, your application, that you need to do this? What do you want to connect to the arduino? Please tell us, there may be another way to do it.

What is your electronics, programming, arduino, hardware experience? What is your country, black and red for neut and active?

Thanks.. Tom... :)

Using Neutral isn't advisable. Although it can work this references the whole circuit to mains.

And connecting PE to N in the house will trip the GFCI/RCD or when not installed, the leakage current on the PE might now flow true the Arduino.

So I agree, your questions shows lack of knowledge about mains so please keep your circuit fully isolated from mains.

OP is nor in USA but in USA NEC requures PE and Neutral connected at POE ( point of entry ( to structure)) so Neutral is at true 0V at POE but may have small voltage drop some distance ( anither room) but this drop should remain small everywhere. If arduuno GND is connected to PE in one room , the voltage on Neutral in another room is not going to be much different. NEC does not allow Neutral to be connected to PE anywhere else other than POE so there will be varying small voltage drops across Neutral throughout structure. If Neutral is at 0V at POE and for example 30 mV at Urduino location and 40 mV at input pullup location then for all practical purposes it is already switched to GND. Also, never use 1 k pullups. Pullups should be 10 k. What scares me about this is that I think OP wants to connect the arduino end of Neutral to a GPIO pin to switch HIGH or LOW. This post is luke a HORROR movie, it gets scarier by the minute.

If I connect Ground wire of 220V to my Arduino GND and I set GND signal using Ground wire of 220V, will I burn my arduino card or it will work?? In theory there is no tension there, but I do not know if AC noises will destroy the board (or chip).

Technically, Arduino GND must be isolated (powered with an isolated DC supply) first, then it could be connected to the ground wire in an AC circuit. Noise on this wire will not affect the Arduino until other signals derived from AC get connected to the Arduino.

What's missing is your application ... measuring AC voltage? AC frequency? Zero cross detection? Other? See TomGeorge's reply.

If you consider opto isolation (or other type of isolation), then you could avoid connecting GND to the Ground wire on an AC circuit.

The OP has a device with a "switch to GND" input (with a pullup resistor) and he wants to use the arduino to switch it GND through the Neutral (at least that was my interpretation). (I know it sounds crazy but I think that's what he meant)

OK, I see that now. Somehow I missed a section of posts on my first read-through. Seems to me that the OP wants to detect if an AC switch is on or off. Will wait for clarification.

dlloyd: Will wait for clarification.

Or not depending if he already tried it and is dead.

Or not depending if he already tried it and is dead.

Who says you can't be grumpy and funny at the same time ? ;D

I don't think it is an AC switch. I think it is a standard industrial active LOW input that is turned on with a simple connection to GND (for simplicity), requiring no logic circuits or experience. All you have to do is switch it to GND to turn the device on but it is a DC circuit input.

jaja, thanks for all your advises.

No, I am not dead. But all of you are right: it is really dangerous. I expect I can just burn the board, but I can even burn my laptop while updating... so, no way.

Thanks for all your comments.

I once designed a remote indicator for a security light for a friend which took 4A at 240vac.

I wound the live feed 2 times round a small ( 3watt ) transformer core, which already had a 300 turn winding.

I now have a 150:1 current transformer I fed the 300 turn winding to a bridge rectifier, which drove a little piezo buzzer.

Put it all in a sealed plastic box to keep prying fingers away

worked fine

regards

Allan.