How to test if I am grounded properly to work with electronics?

Thread Starter

SoulReaver009

Joined Mar 19, 2023
7
Hello people of "All About of Circuits"!,
I am new to electronics. Been fascinated by it for a while, have studied physics (not Electricity, yet, but its my next unit). I got a multimeter and an Ardist DIY kit for my birthday and I am very excited to start testing, experimenting, and building!

I have been googling and youtubing a little bit, watching some reviews on my multimeter, and reading my manual and such.

For some reason I cannot find a video or webpage to test and confirm if I am properly grounded.

I can only work in my room, and it has carpet, so I am very nervous. I cannot work anywhere else, sadly.
I watched a youtube video that said to plug in a 3-prong laptop charger, and then connect the alligator clip of my ESD anti-static wrist strap to the outside metal part of the charger (the part that goes into the laptop).

Lots of people have commented that it works and i believe them. If you know other ways to ground, I would be interested. Would also be cool to test each method of grounding, and compare results.

Being the experimentalist that I am, I would like to have a procedure to test and confirm (as closely to absolutely, as possible) if I am indeed grounded, or at least within a safe range to "work with electronics". please forgive me if my terms or sayings are inaccurate or wrong. I am new to this!

Can't wait to hear back and get started!!
 

tautech

Joined Oct 8, 2019
400
What you are caring about is ESD and how electrostatics discharge could damage components or what you are working on.
There are many ways to look at this as we should not forget some components while having small dynamic ranges can be operated at elevated voltages way beyond where one imagines they would survive.

Take this and apply it to whatever we work on/with in whatever environment where the risk only is the differences in potential between ourselves and components or the DUT.
This has been an issue for decades of technology and there are several ways to deal with it, both complex and simple.
I've always preferred the KISS approach and providing you mind is on the J O B simple procedures like bringing the DUT to the same potential as yourself can save a lot of heartache.
Of highest risk is anything of IC or FET construction and the medium they are contained in has lots to do with how high the risk is.
Conductive antistatic packaging is the norm but once these devices are in circuit they are quite robust unless you exceed their operational ratings.

Typically the pro engineer has a conductive bench mat connected to ground and works with a conductive wrist strap also connected to ground normally with a 1M resistor in series however once ESD sensitive components are placed ( normally last in a design) the wrist strap can be dispensed with unless you are in a highly static environment. Typically synthetic floor coverings and/or low humidity climates are the worst.

Once one is confident/competent simple procedures like touching assemblies (not components) to bring you and the assembly to the same potential is sufficient to reduce ESD risk to negligible levels.
 

MrChips

Joined Oct 2, 2009
30,933
Components as well as complete board assemblies are shipped in antistatic bags and containers.

The accepted industry practice is to continue observing proper ESD handling and safeguards in all stages of PCB assembly.
 

Ya’akov

Joined Jan 27, 2019
9,233
DANGER: Connecting yourself to any part of a mains outlet is a potentially dangerous thing. Proper safety protocols require confirming the proper operating condition of both your outlet and wrist strap before doing this.

The connection from the wrist strap to the grounding point is done through a 1MΩ resistor. The high voltage electrostatic potential the strap is intended to bleed off easily passes through the high resistance but the 120/240V mains can’t produce significant current through that strap.

So the first thing you must do is take your DMM and measure the resistance from the conducting part of the strap to the clip that will connect to ground. It should be approximately 1MΩ. If it is substantially less than this, discard that strap and get another.

Never assume an electrical outlet is wired properly. It is possible for an outlet to be wired in such a way that the potential of the live wire appears on the ground pin. Use a good quality outlet tester to determine that the outlet is, in fact, wired properly before using it as a grounding point for your wrist strap.

Both dangerous conditions above must be true for you to be harmed, but while that makes the risk quite low the consequences can be dire. You could be killed. So, do check before using the setup because while ESD protection is important, a few parts getting zapped is not a comparable tragedy.

Welcome to AAC. Please ask any questions you have and if you see a chance to help someone with what you know, don’t hesitate to add to a thread. I hope you enjoy your new hobby and your time here. This is a great resource for learning and there are some great folks here.
 

Janis59

Joined Aug 21, 2017
1,855
My beloved method for measure is Edisson lamp. Just beforehand keep all human creatures out of the house, then find the phase wire and in the series with lamp tick to the gnd wire. If lamp lights - then wire have contact with earth. How good - that`s good question. Just measure the voltage of this wire against the network zero wire. If took the 100W lamp what corresponds to 100/220=0.5 A, then (guess) seeing the voltage difference the 8 Volts means the gnd equivalent resistance is 8/0.5=16 Ohms. The standard is saying that 8 Ohms are must to be and 4 Ohms must be for heavy duty installations. However many cases there are 12...16...22. Better is with anything but not nothing.

Only the thing You ought to scare, if You realize this experiment, but some human takes one hand the defective gnd wire and another the true gnd wire (neighborous flat girl in the bathtub), then the Judge may give You unnice criminal penalty. Thus, may not to make this experiment in any multi-flat building where You have no a full control.

If exactly that is the case, then only reliable solution is to take the reading by ohmmeter between GND and network zero, but at so weak currents the reading may happen to be rather inaccurate. Worst case even some 10x inaccurate. But at least, if there is less than 10 Ohms, the danger of human touch in time of experiment will harvest the absolute neglibile risk of shock.

About the wrist. Older watch stainless wrists are very well adjusted to be used for hand earthing. But that 1 MOhm must be divided between multiple resistors for safety. The normal 0.125 W resistor is able for 150...175 V only, the 13 mm -15 mm 0.25-0.5 W resistor may withstand 250 V DC, but only 1 W takes the 350 V (and 2 W takes 500-750 V). If the 220 V gives 314 V peak value, then use or 2 pieces smaller or one but massive resistor.
 
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Thread Starter

SoulReaver009

Joined Mar 19, 2023
7
DANGER: Connecting yourself to any part of a mains outlet is a potentially dangerous thing. Proper safety protocols require confirming the proper operating condition of both your outlet and wrist strap before doing this.

The connection from the wrist strap to the grounding point is done through a 1MΩ resistor. The high voltage electrostatic potential the strap is intended to bleed off easily passes through the high resistance but the 120/240V mains can’t produce significant current through that strap.

So the first thing you must do is take your DMM and measure the resistance from the conducting part of the strap to the clip that will connect to ground. It should be approximately 1MΩ. If it is substantially less than this, discard that strap and get another.

Never assume an electrical outlet is wired properly. It is possible for an outlet to be wired in such a way that the potential of the live wire appears on the ground pin. Use a good quality outlet tester to determine that the outlet is, in fact, wired properly before using it as a grounding point for your wrist strap.

Both dangerous conditions above must be true for you to be harmed, but while that makes the risk quite low the consequences can be dire. You could be killed. So, do check before using the setup because while ESD protection is important, a few parts getting zapped is not a comparable tragedy.

Welcome to AAC. Please ask any questions you have and if you see a chance to help someone with what you know, don’t hesitate to add to a thread. I hope you enjoy your new hobby and your time here. This is a great resource for learning and there are some great folks here.
Thank you, I just tested my ESD wrist strap, and it my DMM measured 0.983 MegaOhms, per testing the 2 points you mentioned above. I am guessing that it is acceptable. Thank you for the information about the ground inlet (correct term?) in a wall socket. I did not know that, and I do not want to say the stupid thing I did. Nothing happened, but I realize now, it was a very stupid thing to do. I have lots to learn. And so I will be sticking with low voltage, and low amps, so that if I do make a mistake, I will not be dire.
 

Thread Starter

SoulReaver009

Joined Mar 19, 2023
7
My brother, mentioned that i could take a copper wire and wrap it around my coax cable. We have a coax cable feed into my room that plugs into our main Ethernet/wifi router/station.

Here is a pic of what i did. will this ground me?

The alligator clip is going to my ESD anti-static wrist strap. I tried to measure continuity from the copper wire to the metal piece which contacts my skin, but there was no continuity measured from my DMM. Weirdly enough, there was no continuity from the alligator clip to the metal contact either. So i guess that is normal. My Ohm resistance measured 0.994 MegaOhms from the copper wire to the metal skin contact plate on my ESD strap.

Thank you for reading and thank you all for replying. I'm very cautious. Probably overly cautious, but good habits are developed early. So I'm trying to adopt these habits now. 20230327_102027.jpg
 
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Ya’akov

Joined Jan 27, 2019
9,233
First, if it will work at all, the only relevant part of that wire is the bit that touches exposed metal of the connector. The part around the insulating jacket of the cable does nothing electrical.

Second, the answer is “maybe”. Properly installed, the service entrance of the cable includes a grounding black that connects the outside of the connector to a good earth ground like a cold water pipe. So it might be a good ground. If you measure from the earth ground pin of the outlet to the connector you should see 0V.

Conversely, if you measure from the L (Live) pin, you should see potential. In the US, the live pin will be the smaller one and the voltage should be about 120—but could range from 110-125V. Measuring this voltage is perfectly safe using your DMM as long as you don’t touch the end of the test lead in the L pin of the receptacle.

Your DMM will have a very high resistance so almost no current actually flows. This is done to avoid disturbing any circuit you are testing. Ohm’s Law describes an immutable and unavoidable relationship among voltage (E, or V, for Voltage), current (I, or A, for Amperes or Amps), and resistances (R, measured in Ohms and denoted by the greek letter Ω (omega)).

The formula looks like this:

\[ \mathsf I = \mathsf{ \frac VR } \] 1680004409622.png

You can see from this that the current I is inversely proportional to the resistance R. So if you have 1V into 1Ω the result is 1A. But if you have 1V into .5Ω you get 2A, conversely 1V into 2Ω gets you .5V. The very high resistance of your meter—~10KΩ—means that if you are measuring 120V the current is \( \mathsf{\frac{120V} {10000Ω}} \) or about .012A (12mA—milliamperes, thousands of an amp).

The names we use for these units are from three prominent early researchers in electricity. Ohms law, and the unit for resistance are named after Georg Simon Ohm who worked out the relationship of these three quantities. The unit for current was named after André-Marie Ampère who is considered one of the “fathers of electromagnetism” and describes how many electrons pass a certain point over time. The unit for voltage and the word itself are after Alessandro Volta who experimented with frogs legs after noting they would twitch when exposed to electricity. He is the inventor of the Voltaic Pile, the progenitor of modern batteries. He made his from coins and paper soaked in acid.

The history of the human exploration of electricity is really fascinating involving many brilliant researchers who managed to see things others couldn’t—sometimes at great personal cost when their ideas, later proven correct, conflicted with the status quo and ideas of ”important” scientists. Thankfully, several were stalwart enough to brave the public humiliation and even poverty to continue and gave us access to the amazing truth.

I highly recommend this YouTube series which offers both technical and personal insight into early research into electricity and corrects the record, including revealing women who were critical to scientific progress in electricity but are all but forgotten in the “official history”. Kathy has many other excellent videos as well. This is the first episode:

 
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