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Jeremy Wenrich
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How do I ground my ESD mat to avoid shocking computers?

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I wouldn't be posting if hours of searching yielded the answer(s) I need. My apologies if this is common knowledge. I searched through questions here and was unable to find anything helpful for my situation. To my question:

I purchased an ESD mat from a local shop today and a piece that snaps to the mat was included. As well as connecting a wrist strap to this piece, it has a 15' tail with a metal ring at the end for grounding. How exactly do I ground with this metal loop? Do I connect to 'the ground hole' on a wall outlet? If so, how? Also, if this is NOT an option in my environment how would I ground? I'm trying to avoid running a copper cord out a window attached to a stake that is driven into the ground...

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Edited by: Sam Lionheart ( ) , Jeremy Wenrich ( )

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Alan
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Ignore crg000's suggestion. DO NOT ground it to your house wiring. The electrical ground for your house is solely for dissipating stray voltages from wiring faults. By wiring your anti-static system to that, you'd be connecting your wrist to the same circuit. If something goes wrong in your house wiring while you're strapped into that, you won't be doing many more repairs.

A water pipe or radiator makes a much better and safer static ground.

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steve
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The ESD association sets the standards for removal of static in electronic manufacturing. 99% of the US manufacturers and 75% of electronic manufacturers world wide use ANSI/ESD S20.20-2007 (written by them)as THE gold standard. For more on their mission visit esda.org

The reason they recommend attachment to an electrical ground is the anti static mats have a very high level of electrical resistance. About 100 Meg Ohms. Enough to slow and control the rate of static discharge and for safety! It's virtually impossible for stray voltages to come thru them or an esd wrist strap.

Radiators rust, water pipes change potential. The only truly reliable ground is an electrical ground that has been (easily) tested. Attachment to the center screw of an AC face plate cover is standard industry accepted method of grounding your mat.

Incidentally all computers are manufactured in a static controlled environment. It's foolish to risk taking the chance with static. The manufacturers don't - for a very good reason - improper static control cost them money and aggravation.

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steve
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Sorry Allan, you're wrong.

The ESD Association recommends attachment to AC electrical ground. The standard method of attachment is to attach the ring terminal from the mat to the center screw of the grounded AC face plate cover.

On occasion attaching to a water pipe or ground rod is a safety hazard and may cause an electrical shock due to the difference in potential between that of the electrical ground and that of the earth ground.

Sorry Steve, the ESD Association - which I gather exists primarily to help manufacturers sell ESD equipment - is wrong. No human should attach him or herself to an AC mains ground. As I explained, the sole purpose of the mains ground is to dissipate stray voltages from faulty wiring. They're not for static or RF, which is why lightning rods and radio antennas aren't supposed to be grounded to them, either. As Jeremy pointed out, there's also no guarantee the mains ground itself is working properly. Plug yourself into the "ground" wire in an old house, and you may wake up with a paramedic taking your pulse - if you're lucky. Differences in ground between the mains and the plumbing pipe don't matter, because the mains ground shouldn't be in the circuit in the first place.

Alan,

Alan - Sorry Steve is correct (as well as the ESD Assoc.) - Lets say the outlet you have at your work area is incorrectly wired (black wire going to the chrome screw, it needs to go to the brass to be correctly wired) If you had used either the water pipe or ground screw you would have been zapped! - Lets say your outlet was correctly wired, using a ground tester to double check every couple of months. Using a proper ESD mat and strap you won't get zapped. As there is a load resistor in each to prevent you from being zapped when working on live equipment. - If you had used the water pipe you could have put your self at a higher risk of a leaking three phase (220 or even 440) The load resistors in your ESD mat and strap could not protect you in that case - RIP ;-{

Dan,

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Scott
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I am an aviation electrician. I have recieved allot of training and electrostatic and electricity are kinda a big thing for me. I agree with steve to hookit up to your wall. With the way electricity works there is absolutaly no way the electricity in your house will harm you unless the ground of the house itself is faulty. E;etricity always follows the path of least resistance which is why things short out. If you have a circuit set up to where it goes from the source to a ground it is shorting itself, and if you decided to place a lightbulb in the circuit after the ground the current would still go to the ground and the lightbulb would not get any power. Also if you have the circuit where it goes from source to load, or lightbulb in this case, and then to a ground, the light blb will light. Remove the ground and there is no light, there is no current. but if you simply add a ground before the lightbulb then it will short and you will have no light. With the way an esd mat is made and allong with the strap, they have resistance, especially the wrist strap because it has a resister in it that should measure around 1 mega ohm, anyway with the amount of resistance at hand electricity follows the path of least resistance and you will be safe.

Resource

http://science.howstuffworks.com/electri...

http://www.pfeiffereng.com/Principals%20...

Edited by: Scott ( )

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BeenThere DoneThat
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Steve was right when he stated,:

"The reason they recommend attachment to an electrical ground is the anti static mats have a very high level of electrical resistance. About 100 Meg Ohms. Enough to slow and control the rate of static discharge and for safety! It's virtually impossible for stray voltages to come thru them or an esd wrist strap."

It is important as other have said not to hook yourself directly to ground. That's why these wrist straps and bench mat cords have resistors in them, to limit the current if you do get across stray voltages.

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mayer
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If your wall plugs are not grounded, get it to a water or gas pipe or radiator. I haven't seen this type but you could run some bare copper wire through the hole and tighten it around the pipe.

Edited by: mayer ( )

If the wall plug is grounded, remove the center screw then replace it through the ring.

mayer,

What would a service center do?

Jeremy Wenrich,

A service center would have grounded plugs.

mayer,

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Leigh Masson
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ESD Is very real.

If you don't ground yourself, you are likely to irreversible damage the computer.

Michael above, has the wrong idea.. I wouldn't be taking my computer to him to be fixed!

You cannot see ESD damage, but it literally blows 'holes' through circuit boards on a microscopic level.

We all know how tiny circuits are.

If you 'zap' a board, you wont know about it- it can be very hard to diagnose why the computer is acting up in a strange way.

You might blame software, drivers or an incompatibility for that BSOD, or just say 'that computer part is just a dud', very few blame ESD.

At my work, we always use ESD protection;

I work on Mac- we use esd wrist strap (to take away static from our bodies) connected to an ESD matt to take static away from the mac, which are then connected to a ground outlet. We use a air filter/ polariser (i might have the wrong terminology) to even take moisture out of the air (moisture can conduct static through the air).

We clean the matt with a special spray every day to ensure it remains esd safe.

I can't however share much other knowledge on how to set it up properly with grounding etc, other than to say 'be careful'...

I wish iFixit would create a whole kit (esd Mat, strap, a grounding plug (to make it easy to ground! spray and maybe even an air filter)... and a set of instructions - it'd clear the air a little on how to set up.

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Amar
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A couple of good webpages with diagrams on setting up an esd work station are at:

ESD Mat Workstation Setup

http://www.esdproduct.com/how_to_install...

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John
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If anyone is concerned about possibly getting household AC voltages on your wrist strap, consider this:

Standard ESD wrist straps should have a 1 million ohm resistance. If the ground wire were attached directly to 120VAC, you could experience at most 120 microamps of current through your body (and that neglects your resistance, which is usually in the hundreds of thousands of ohms). OSHA claims that most people can't even perceive currents lower than about 1mA, and we're talking about 1/8 of that current here.

If you have a proper wrist strap, then you're very unlikely to electrocute yourself, even if you plug right into the hot line.

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assortedrubbish
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I'm curious about something here, how do many technicians imagine that an ESD mat is used or required ?

It's not supposed to be connected to live or grounded things to remove household electricity, it's to discharge the built-up static from ourselves as we move around.

As we move, we make up a static charge, any kind of movement where there is friction creates this effect. Rubber and other non-conductive chemicals don't allow this to happen, or to be more accurate they just reduce the flow of atoms to so few it become next to nothing.

A neat test as I use to show students, is to buy one of them $1 screwdriver/mains testers, looks like a flat blade screwdriver but has a red LED - this lights when it senses power, and especially when it picks up static - I have students walk over different surfaces, wearing different shoes, clothing etc. Try bare feet and a nice woolly sweatshirt lol.

Anyway, the idea is this, as far as I see it to be (like electricity, there are many ideas of just what it is). . . .

You, and your circuit will/may have current in them - certainly you 'will' create current as you move while working. This is a danger to any complex circuit using degradable low power components, so you want that spare current to all go away.

This is impossible completely because you add more as you touch the circuit, your tools, the floor etc. Friction = power :-(

Your ESD mat is a convenient way to 'slowly' take away unwanted power - nothing more than that. Your ESD strap on your wrist is the same, but just a personal version of the same thing.

You use both (mat and strap), because the circuit will have your static slowly wandering thru it, and if you touch one end of a long circuit to the ESD mat and the other has your fingers on it (as an example) you will flow power thru it (in theory) as you will work like a battery power cell until all your personal static is drained away.

The ESD mat slows the flow right down, thereby making the rush of electrons nowhere near so harmful. Keep in mind what electricity is - it's only dangerous/electrified if its atoms are moving fast enough - if you slow it down, it becomes low power and harmless (again, in theory).

The ESD strap instead, drains power from you, more efficiently/quickly onto whatever 'grounded' object that you are connected to, than a mat will do - obviously a mat will only be of use if bare parts of the board are in contact with the mat itself.

It doesn't necessarily need to be to a house etc. that you are strapped onto, as static only zaps when it jumps suddenly, but if in constant contact thru a strap/mat, it flows instead, again slowly because of the straps/mats resistance.

Try this one - do you get a zap when you touch a car door? or a kitchen sink? Why? because of that sudden zap - power looking for an escape. Now, go to your car door after rubbing your feet all over a carpet, rubbing a curtain etc. Make sure you cover your hand in a towel (dry), put the towel in contact with the door first, press it against it, now slide your hand along the towel onto the cars metal door surface, and.....no zap. The towel takes it away by working exactly the same as a strap would - slows that initial zap/shock.

Any strap or mat just needs to ground to something that will logically be big enough to have enough atoms to take the shock, regardless of it actually going to the earths surface - although that's obviously quite big lol. The reason for using the planet as a ground, is its size - nobody ever sees sparks as they walk across the floor, because the earth gives too much resistance for the foot/floor circuit to work.

Here in the UK, we have the ground wire too, which makes it all soooo much easier, but the reality is, you dont need it to be going to actual ground, just something big enough to take it.

Sorry for ranting !! I gotta stop drinking so much cola on hot days lol :-)

You make some good points here! It does take a little time for the static buildup to discharge thru either the mat or strap to ground (you should wait 2 seconds before touching). And, yes the goal here is not ground per-say but to bring all of the objects in use to the same electro-motive potential. Ground is used as it is in theory at the same potential. What is important to making sure the ground used by the device being worked in (if powered by a power feed) is tied to the same ground so they are at the same potential. And your correct the ability to dissipate the charge (drain) is also important, hence using ground offers this as well (as long at it is correctly wired). Here in the states we do have a three wired power system for all new construction, but just like you some older houses still have a two wire solution (or the person wiring the outlet sorta forgets to wire the third connection).

Dan,

A small correction: The wrist strap needs to be connected to the mat not independently to ground. If you don't have a mat (i.e. working on equipment held in on a rack) then you clip your self to the powered equipment's chassis. The only time you need a mat is when you have removed a logic board and/or are working on ESD sensitive sub assemblies. You could also bond the board or equipment to the a protected ground post on the bench using a ESD bench lead (has a load resistor inline to ground). I use all these methods depending on what I am doing.

Dan,

In all cases it is very important to store the ESD sensitive part/s in proper ESD protective packaging (you should not use the pink poly bags only the metal film bags for PCB's). As well as use the non-static pink foam and carbon black boxes for packaging if needed.

Dan,

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Brenton Pettitt
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Is it necessary to switch on a GPO socket with an ESD plug ie., with only the earth pin of the plug wired?. In other words is earth always available?

Here's a good writeup on General Purpose Outlets (GPO)

Dan,

This is a tricky question as your country may have different rules. Here in the states the ground pin is the first contact to be made when mating into a socket (slightly longer pin) and by law ground must be constantly connected (not switched). In my worldwide travels I have never found a European or Asian country outlet that wasn't the same even when the outlet has a switch on it. But, thats not to say some older wired outlets in some countries may be different. Common sense tells me it should be but you know common sense doesn't always apply ;-} I would strongly recommend checking it out with a Ohm meter wiring on lead to a ground source and the other end into the outlet ground. First check voltage just incase you have a wiring fault and don't touch the exposed probe ends when you measure.

Dan,

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crg000
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Turn the power off to the closest outlet, remove the wall plate and connect the ring to the bare copper wire "ground" the wire could also be green.

I talked to my uncle who is an electrician but not a computer repair man. He urged me not to connect to the "ground" of an outlet. His reasons were three fold. (1) The home may be older and no ground may be available. (2) The ground may not have been installed properly during a remodel or for other reasons is no longer functioning as a ground. (3) All grounds in the home are connected and if there is a slight discharge moving through them and I happen to make a better ground than the home's ground then I could potentially damage the computer and shock myself.

Jeremy Wenrich,

Radio shack sells grounding testers that just plug into the outlet. If your uncle is an electrician, I would do what he tells you to to ground it.

mayer,

Your uncle may have assumed you where connecting your self directly to this ground point (bare copper wire around your arm) while working on live equipment. If that were the case he was correct, But! A proper ESD mat and strap have a resistive load to protect you from 110 voltage so it's not a direct ground path and yet can dissipate any static charge. In any case you should buy a simple outlet tester to make sure the outlet is correctly wired before connecting a mat to it and make sure to use this outlet for powering up any equipment your working on.

Dan,

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Jeremy Wenrich
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I've done a lot of research in the last couple days and gotten several responses from different sources. There seem to be 3 major schools of thought when it comes to ESD safety.

(1) Minimal protection is required, if any at all. Plenty of people claim to simply touch objects around them and avoid moonwalking across carpet. That is sufficient to avoid damaging computer equipment.

(2) Connecting to the ground of a receptacle is normal procedure and perfectly safe. "The ground" of a receptacle is there for a reason, right?

(3) The only safe and reliable way to ground an ESD mat, and one's self, is to pound a stake into the ground. If this isn't possible at least connect to an unpainted metal pipe or structural material that leads to the ground. Connecting to any system where there are unknowns carries a small risk, but a risk nonetheless. Even testing the ground of a receptacle may not be accurate enough as there are too many variables.

So, it seems that for the simple RAM install on a shoe string budget, the first is just fine. Typical servicing and PC building is probably well suited for the second, especially when working in the same trusted environment. Lastly, when absolute certainty is desired, connecting to unpainted metal pipes or, better yet, creating one's own ground with a stake driven into mother earth gives the greatest assurance. Anyone doing house calls or working on other people's expensive computers might be best served by considering the last option despite the extra annoyances that go into it.

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Ed Gaulden
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My grounding scheme is that all of my ham radio equipment is grounded to a common tie-in point. From the tie-in point the common-point ground goes under the house and then outdoors to an 8' copper-clad ground rod.

The interesting thing is that both the ground rod and the household grounding are at the same potential -- however, the radio equipment is separate from the house grounding.

The Radio Shack anti-static mat and wrist strap says on its instructions that you should plug the strap into the mat and then plug the mat "to any available ground." Its next helpful instruction goes on to say, "Or, you can remove the alligator clip and plug the grounding cord's banana plug into the round ground hole on a standard AC outlet."

I have used both grounding methods and have have never suffered any shock. The thing is that you are THE "end of the wire" holding/carrying a possible negative charge needing to go someplace, thus to ground. IF you have your computer still plugged in, or my ham radio equipment, or whatever you are working on -- still plugged in -- THEN YOU COULD BE ELECTROCUTED, completing an unknown circuit!!

Your radio gear ground is to protect you and the equipment from lightning not exposure from working on the equipment. If you were working on your gear you would disconnect the antenna leads and other connections move it over to a work bench to open it up on an ESD mat with a wrist strap connected to the outlet ground. Granted this is the SAME ground but used DIFFERENTLY.

Dan,

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Petr
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Hi all,

After bad experiences during PC and radios repairing I decided to solve my ESD protection in the kitchen "lab" property.

I would like to share my experiences with ESD mats for safe, ESD protective soldering as it can help to others. I looked for long time on the eBay and other shops for possibility to purchase small portable ESD mats including the cables to connect for same el. potential or directly to common ground.

All mats which I found were big and expensive or small but expensive or small, not high quality just vinyl and expensive etc. Requested parameters were: two layers, oil, grease and solvent resistant, high temp resistant, acid proof and knife cut proof material.

After long time I returned back to Czech market where I found the company where they has exactly what I looked for but unfortunately the mats was too big. Standard size is 80cm x 160cm for high price dedicated for professional industrial usage. So I tried to call them and after some negotiation they promised to cut it for me to preffered size 40x60cm and install the cables and bananas for ground connection.

We also reached after some phone calls negotiation an excellent price.

Parameters:

- thickness: 2mm

- RTG = 10^6 – 10^8

This branded R2 Ultra/Antistat ESD Rubber Mats have two layers; the top one is a blue static dissipative rubber layer laminated to a black conductive rubber bottom layer. Surface resistivity of the top layer is 10^6 – 10^8 and bottom layer is 10^5 – 10^6. This ESD Rubber material offers excellent resistance to oil, grease and most common solvent. These ESD Rubber Mats are very light compared to single layer and three layer mats.

After ordering and arrival at home I decided to make several tests:

Several oils, greases and different solvents and mat survived without any damages.

The flare-up point and it seems to be higher than 1000 C which is corresponding to almost 2000 F. (I was limited by temp sensors and thermometer over here)

The burning thru temperature and it survived 450 C for 2mins which is

corresponding to 850 F. (I was limited by my soldering station, hi)

The max of the temp without any noticeable damage of the top layer. It survived 200 C for 2mins which is corresponding to 400 F.

Finaly I tried to cut it using standard knife and make the hole thru using drill and it proved very high resistance.

The complete set including the 60x40cm high durability ESD mat, grounding snap points, wristband, coiled wires including the 1MOhms resistors to limit the current, banana socket and aligator clip. The set is ready to use. I never had any ESD issues with this protection when i repaired PC, radios etc.

All these tests results are so great that I am really happy with this new ESD mat and I am sure that it will make great job.

RESUME:

To get best price from supplier we ordered with local friends higher amount of the sets so I have rest of them available for sale. If You would like to get this ESD mats also then let me know OFF-LIST to indians@xsmail.com

I am ready to help You with purchasing, repacking and shipping to you worldwide.

Hope it will help to some of You as same as to me with safe soldering in the kitchen property...

Sorry for a bit longer message and bothering other people but I guess it can help to many of us with ESD issue.

PetrO

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Michel
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I dont worry about static. i build computers and have never had any problems. and the computer shop i work at, nobody worries about it, nor has anyone had any problems.

You need to do some reading on ESD its real and you are just hurting your equipments lifespan.

Dan,

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blair
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These answers are all over the place and very conflicting.

I couldn't imagine hooking a wristband / mat to the ground of an electrical outlet, even if you have tested it to be safe. At any time, if there is an electrical fault caused by anything (rat chewing through wire, poor electrical work done while installing something, dropping hair-dryer in sink, etc.) on the circuit in your house / office, you're gonna get 120 AC volts running though the ground wire in your electrical system. It will probably only be momentary till a breaker faults, but if you have a strap around your wrist hooked to an AC outlet ground and such a fault occurs, your gonna get shocked badly. It's not gonna be like accidentally touching an exposed wire, cause your gonna have that strap around your wrist designed to make the best electrical contact. That type of shock could seriously injure you.

Not all mats / straps have a 100 Meg Ohm resister in them. Actually only the more expensive ones have such a resistor. Most that are under $150 have only a 2-4 megohm resistor. That resistor wouldn't do anything to remedy this dangerous issue.

The office I moved into 6 yrs ago had changes made by shotty contractors before I moved in, and I wouldn't ever think of using the AC ground.

While I worked on the maintenance staff at a school, I once went to turn on the light in a shed after someone had earlier installed the light in that shed, and as soon as my fingers touched the metal of the switch case I got shocked. The guy who installed the light made a mistake. If I were to take a strap and wrap it around my wrist and attach it to the ground of that box I don't think that would turn out well.

The truth is that there is no easy answer for this issue.

For now my strap / mat is grounded to the fire sprinkler on my ceiling. I know that's not the best, but it sure has eliminated obvious static discharge I used to get quite often. Before I hooked my band to the sprinkler, I'd have a hard drive, (for example), that I removed from a laptop hooked up to a computer to image the drive, and during the process, if I touched the drive I'd get an obvious static discharge and the imaging process would immediately fail. This occurs even though my office floor is laminate Static discharge while performing even mundane computer repair tasks is a serious issue.

Until I get a wire run from a stake in the ground up to the second floor of my building where my office is, I will have to use my fire sprinkler as a ground.

AC OUTLET GROUND = BAD.

If anyone has any better ideas I'd love to hear them... really! Please! It's a tough topic!

The problem you are facing here is the lack of understanding what a ESD wrist strap and/or mat does electrically speaking. From the surface people think you'er taking a bare wire held in your teeth and plugging the other end into a live outlet! Sorry to say thats not whats being done here! The AC sockets GROUND is what you most likely want to use as the ground point (using a water line could also be workable if tested). The wrist strap as well as the mat have a 1 meg ohm resistor isolating you from the direct ground path so you don't get shocked if you happen to touch a live 120 volt connection. Of course you do need to check your ground services and make sure you are using a good quality wrist strap and mat and not using someones home brew solution.

Dan,

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