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

[SoulReaver009]

Hello people of "EEVBlog"!,
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!!

[jonpaul]

Bonjour cher Monsieur

If,you restricted your first projects to low voltage, eg 5, 12, 15V battery or wall transformers powered, you have no issues with ground.

If,you build,mains powered or high voltage equipment then there is,a potential shock hazard.

To test a,ground, measure the resistance between earth ( cold water pipe, electric box grounded housing or,metal conduit) and the ground under test, should be under 25 Ohms, really near 0..1 ohm.


for info on safety ground, see Mike Holt.com or a professional electrical forum.


Bon courage

Jon

[james_s]

Most modern stuff is pretty robust so if it's just hobby circuits I wouldn't worry about it too much, if you're working on expensive gear, production circuits that will go to paying customers or handling old CMOS ICs then ESD control is far more important. You can wear a static dissipating wrist strap if you're worried about it, and ESD bench mats are readily available.

[SoulReaver009]

I would like to know how to test my body to confirm i am grounded.

surprisingly, I cannot find any procedures on this anywhere.

I thought it would be one of the first steps in testing, and tinkering with electronics.

While, your message to me does reassure me, I would also like the joy of testing and confirming it.  I am surprised there is no easily findable procedure on this.

[SoulReaver009]

How do I test myself tho?

I am surprised to not find any procedure on how to do this.  I would've thought this wouldve been the first thing your taught, in testing and tinkering.

Kind of like how, print "hello world" is the first thing ur taught when learning to program. haha

If you know of a way to do this, I would greatly appreciate it. 

[Stray Electron]

  Take a look at item 154377536864 on Ebay.  The company that I worked for could have had anything on the market but all of their testers were made by 3M.


  If you want to know more, here is a manual for the 3M 740 model.  https://www.pctronics.com.br/manuais/740-5702c659c9043.pdf

[pcprogrammer]

Like james_s wrote I would not worry to much about it. I have worked on many stuff throughout my life and not bothered with grounding myself through a strap while working with simple cheap stuff. Nothing got damaged so far.

When should you worry is when you notice to be very static often. For instance when you touch a big body of steel and zap you feel the spark. (Heating radiators or big computer cases, etc) Or when you touch the ground pin directly and you feel the spark.

[tooki]

Like james_s wrote I would not worry to much about it. I have worked on many stuff throughout my life and not bothered with grounding myself through a strap while working with simple cheap stuff. Nothing got damaged so far.

I think it’s important to mention that this argument is a very, very weak one: one rarely knows if they’ve caused ESD damage, because it often manifests as a problem down the line, for example as a component that fails after a few years, or that works but is no longer in-spec.

See e.g.
http://www.cisl.columbia.edu/courses/spring-2002/ee6930/papers/00899057.pdf
https://www.ti.com/lit/an/ssya010a/ssya010a.pdf
https://catalogimages.wiley.com/images/db/pdf/9780470511374.excerpt.pdf

I’ll be honest that I rarely use an ESD strap, but I do use an ESD mat. At home I am normally barefoot, which produces less static than wearing insulating shoes, and at work I wear ESD slippers instead of shoes, for the same reason. (At my previous job we had actual ESD flooring, so straps truly weren’t necessary. I’ve considered buying an anti-fatigue ESD floor mat for at home to accomplish the same thing.) When I worked in the field doing computer service, we normally just kept the system plugged in but turned off to maintain the ground connection, frequently touching bare metal of the case to ensure equipotential.

I also found this interesting guide while searching, on how to protect circuits:
https://www.ti.com/lit/sg/sszb130d/sszb130d.pdf

[pcprogrammer]

I think it’s important to mention that this argument is a very, very weak one: one rarely knows if they’ve caused ESD damage, because it often manifests as a problem down the line, for example as a component that fails after a few years, or that works but is no longer in-spec.

True, but for a hobbyist not a big deal. With computers I do the same as you, keep the case grounded and touch it once in a while. When working with small MCU boards I don't bother. When I carry them between my two work spaces (up and down the stairs) I keep them in their anti static bags, but on my computer desk they lie on the desk and get connected and disconnected via USB a lot. The computer is grounded though.

When one gets a job working in a lab, they most likely will have guidelines and tools that need to be followed and used.

But on the subject Linus did a video with someone and an ESD gun to test the effect on memory boards. They can take quite the beating, although they did not look into longer term effects.

[Shock]

This depends on your geographic location as some people don't have earthed/grounded household mains power outlets.

Typically you would attach your wrist strap to your soldering station or esd mat, or your esd socket on your workbench. Aside from the soldering station (which connects to the mains directly) these then connect to a earth/grounding bond plug that you plug into your mains power outlet.

So looks something like this:
Wrist strap >> ESD mat >> Bond plug >> Mains
Wrist strap >> Soldering station >> Mains
Wrist strap >> Bench socket >> Bond plug >> Mains
From there your household mains connects your electrical grid and ground/earth rod.

To test your wrist straps connections you can use a multimeter on ohms and measure the resistance between the button on your wrist strap and the unplugged (removed from the mains) ground/earth pin of your bond plug.

You will normally see up to a couple of megaohms resistance. This resistance helps avoid being electrocuted easily, connected directly to the earth/ground with no resistance is a bad idea as it makes a high current path.

You can also follow something like this which gives instructions on how to perform a functional test the wrist strap while wearing it. https://www.newark.com/pdfs/techarticles/3M/wristStrapFuntionalTesting.pdf

To test if your mains outlets are wired correctly you can use an outlet tester which lights up LEDs to indicate incorrect or missing wiring.

Don't mess with the mains or go near the grounding rod. You need a bunch of experience and in most cases trained and licensed to understand how not to get electrocuted and test the household mains properly.

I'd avoid the Chinese wrist straps as many are fake and do nothing, save up and buy a genuine 3M branded one from a reliable source (as ebay and amazon will have counterfeits). https://docs.rs-online.com/3e6e/0900766b81446fd1.pdf

A static dissipative ESD mat is the next thing to get, but the idea is work as best as you can with what you have.

[bidrohini1]

Here is a discussion about how to ground yourself:

[Shock]

You could also try testing the wrist strap separately off your body. You should be able to use some household aluminum foil folded in a strip and use clothes pegs or paper clips to secure it around the inside of the strap. Test that you have a 1-2 megaohms resistance between the foil and the end of the wrist strap cable and unplugged mains bond plug earth/ground pin. After you have confirmed this pass some current through the whole circuit from a 9V battery or your bench supply. It should be under 10mA or 100uW with those resistances in place.

By using the voltage drop method you can measure volts or millivolts between the foil and button on the strap and between the foil and the other end of the cable and between the cable and the bond plug pin. Manipulate the foil to see where the conductive parts of the strap are.

You can of course try measuring current if your multimeter goes this low but check ohms law first. If there is no or low resistance and you are putting non limited current through your multimeter (high current) you can blow your fuse or break a cheap multimeter. Not only that, your 9V battery may catch on fire or if you don't have OC or current limiting protection on your power supply it's not a good idea.

[AndyC_772]

they did not look into longer term effects.

On that basis, smoking is safe, X-rays are harmless and it's perfectly OK to breathe asbestos.

Joking aside, this is a really important point that many - if not most - people working with electronics seem not to 'get'. ESD doesn't necessarily stop something working completely and immediately, but it can decrease long-term reliability, or just cause a part to no longer meet specification.

What's particularly odd, not to mention frustrating for anyone who has had the training and worked in a proper ESD-safe environment, is the sheer number of people who are actively resistent to the idea that they need to follow correct ESD precautions. ESD is cold, hard science - yet for some reason people who might ordinarily relish opportunities to show off their technical knowledge and skill instead recoil from the idea that ESD is a thing, that it matters, and that they might be unknowingly damaging their brand new games machine by failing to follow some really simple precautions.

I even saw this in a former job, where I was the senior hardware engineer. From time to time people (software engineers, working on PC plug-in cards) would hand me boards and say, in a disparaging tone, "it just stopped working", as though it were somehow my fault.

After a while I got sick of this, ordered a roll of ESD matting, and one evening after everyone had gone home, I went round installing ESD mats on the desks of all the software engineers. It didn't go down well, and I even had someone say in so many words "you don't actually expect us to use this stuff, do you?".

Yes. Yes, I do. Because science.

Nobody ever handed me a board that "just stopped working" again.

[m k]

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

Being professional with it is not easy.

If your multimeter has a peak hold use that.
Set the meter to high current and connect one lead to ground and other to something you're going to discharge your self.
Select discharge thingy so big that you can slap it, zap is not so nasty if you slap the conduit and strong zap can be truly nasty but for that you need more energy than just static of you.

Then just start experimenting.
Shoes and floor are major things, chair and clothes surprisingly less.
You can obviously generate more charge with bad clothes but shoes and floor are doing it naturally.

I've measured 10A from me to ground.
Actual peak is most likely much higher.

Finally you just must believe that no zap means your potential is the same.

I use wrist wrap when I have it.
Other times I touch metal frame every now and then and try to move less.

In case you're zapped when exiting a car just grab metal door frame early on.

If I remember correctly 3/4 of zaps are damaging only partially.
Means that the device is still somewhat operational.
One test device included a socket for two pins, a buzzer and a component with four legs.
Two extra legs were not connected, touching one of those silenced the buzzer and the other made it buzzing again, until it didn't.

[richnormand]

For my bench at home and the computer bench I have esd dissipative flooring (stapled over 3/8" plywood ) on the carpet (and properly grounded, see at the corner on the photos). They are connected to the ground of the electrical outlet.
ESD straps are through a 1M resistor for safety.

The mats were from ebay (except the GamesNexus that was a gift for the sem) . Some large companies (US, Canada) have remnants from contracts and sometime sell the leftover stuff at discount on ebay. The sizes are plenty for a small bench and they get recycled  instead of going in the dumpster but you might not get your choice of colour (see the crappy poo brown flooring for the main bench....) Much better quality than what I found from cheap stuff from China.

For testing, if you have a megger or an electrometer (Keithley 617), but you can also find testers sometime on ebay. The real test is that in winter (low humidity from heating) my monitor does not reset when I touch the keyboard now ....
Maybe a bit overdone for a home setup but I do get things that are pretty expensive to rework from friends sometime (like a main board smd repair from a Hitachi SEM a few months ago or similar stuff).

Don't forget that esd damage can be cumulative and has been shown to result in increased failures several month down the line. You can find several photos on the web from failure analysis companies on this.

I would encourage you to do it properly, with good stuff and it will last a lifetime.

[Infraviolet]

Another point to mention is protecting things from ESD when storing or moving them, a lot of common packing materials give of so much static you can feel it in the hairs on the backs of your hands. Getting the silvery or pink electrostatic bags (keep as spares those which come when you buy components in them) can help,and for big boards need more mechanically sound wrapping to be transpoted or store the pink anti-static bubble wrap is a good idea.

I don't think I've ever encountered, knowingly, an ESD issue. But I've mostly worked with components which are not the latest and fanciest, and haven't done much with bare field effect transistors (the FETs inside larger ICs usually have some protection diodes within the overall chip). And I'm in the UK where, I think, the climate isn't as ESD incuding as drier centre-of-continent climates are. Plus I don't tend to wear wool or other "fluffy" fibres. I would swear by a wrist-strap to mains earth as a precaution whe working on a computer's insides or anything expensive, we used a lot of anti-static stuff in a job I once had involving £100K boards with fancy ASICs on them, at another job I had where the most expensive component used was <£10 nobody but myself took any ESD precuations and all I took was grabbing something earthed for a few seconds upon first entering the room.

[james_s]

I have definitely damaged parts from ESD, at least I very strongly suspect that's what happened. I have only experienced this with SRAM and DRAM though, the former in particular seems to be especially fragile. Laser diodes are also known to be fragile, especially older ones.

I'm not meaning to minimize the importance of ESD precautions, but if you're a hobbyist playing with an Arduino for example, the chances of damaging a part to the point that it malfunctions seems to be minimal and most of the stuff is cheap enough that it doesn't seem like a big deal. The greatest cost is frustration should something be not working properly. I am much more careful when it's winter and the air is dry causing me to get zaps all over than the rest of the year when the humidity is much higher.

[AndyC_772]

Being professional with it is not easy.

If your multimeter has a peak hold use that.
Set the meter to high current and connect one lead to ground and other to something you're going to discharge your self.

An ESD event is far too short to be measured by a multimeter.

Ironically, that's why they're damaging in the first place; it's not that they contain a great deal of energy, but that they transfer it from one place to another in a very short time - hence a very large current, and enormous I2R heating of a very tiny transistor inside whatever device you're handling.

If your meter reads anything, it's more likely because an ESD discharge results in very high frequency RF interference being generated, which couples into the meter's input circuits and causes a temporary read error.

I've been to EMC labs where equipment resets (or otherwise misbehaves) during ESD testing; it's not the flow of current through the board's GND plane that causes the fault, but radiated RFI from the spark coupling into digital logic.

[m k]

An ESD event is far too short to be measured by a multimeter.

Have you tried?

I remember that my old Fluke 77 was pretty rational, small zap and small current type rational.
Though the set is obviously also quite small, zapping constantly is uncomfortable.
And categorizing small and big by feeling is also a bit less scientific.

What I can't remember is how the zap happened through the wrist wrap.

[AndyC_772]

Compare and contrast the frequency spectrum of an ESD event with the manufacturer's stated bandwidth of the meter.

[m k]

Yes, but can that energy actually flow differently.
If I see an arc of current is it timely true and/or accurate.
Everybody with regular eyes can see camera flashes but how fast is too fast.
Lightning has an after glow but is it same with mini zap.

[Siwastaja]

It's not that you build up significant static charges suddenly out of blue. Unless you are working with some super-sensitive special RF MOSFETs in production where 0.0000% failure rate must be maintained, you don't need to use actual grounding strap at all. ESD mat grounded through a 1Mohm resistor on your working table is more than enough practice for hobby or professional prototyping and manufacture (most sensitive special circuits or red tape requirements from quality assurance systems aside), because your arms rest on that mat most of the time, and even if you are "ungrounded" for some seconds, no significant charges build up.

This is not to say ESD practices are completely useless, not at all. Sane level of ESD protection stops mysterious failures which otherwise take a lot of time and effort to debug as you don't know exactly where the problem is. The same as using those 0.1uF decoupling caps on every power pin of an MCU as the datasheet suggests.

[Terry Bites]

To my shame I'll admit that I've never really bothered with antistatic precautions. I can only recall (no I'm not senile) one occasion where I zapped a board or a semiconductor with static. A small signal mosfet.
Thats once in 50 years of electronics.
It was a winter's day in rainy London and I was..... rambling.

[tooki]

I think it’s important to mention that this argument is a very, very weak one: one rarely knows if they’ve caused ESD damage, because it often manifests as a problem down the line, for example as a component that fails after a few years, or that works but is no longer in-spec.

True, but for a hobbyist not a big deal.

That doesn’t make sense. A sensitive part can’t tell that you’re a hobbyist and become more forgiving. A damaged part is equally damaged whether you’re a company or hobbyist. Just because you’re your own customer doesn’t mean you’re any happier about a failed or compromised part.

[pcprogrammer]

I think it’s important to mention that this argument is a very, very weak one: one rarely knows if they’ve caused ESD damage, because it often manifests as a problem down the line, for example as a component that fails after a few years, or that works but is no longer in-spec.

True, but for a hobbyist not a big deal.

That doesn’t make sense. A sensitive part can’t tell that you’re a hobbyist and become more forgiving. A damaged part is equally damaged whether you’re a company or hobbyist. Just because you’re your own customer doesn’t mean you’re any happier about a failed or compromised part.

I meant that money wise. I don't care if a 2$ proto board gets damaged due to ESD. Sure it can be a pain in the ass to figure out why it is not working properly, but just like Terry Bites, in the ~40 years of playing and working with electronics, I can't recall something failing on me due to ESD. Latest bigger thing I build, also containing mosfets, is working fine, day in and day out for >4 years. Only thing that died in it was an old PC power supply. ESD, I doubt it. Old age more likely, being from a system from <1996.