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At work I have the problem that I seem to collect a lot of static charge as soon as I leave my desk and return. I am not quite sure why this happens. Strangely enough the effect is stronger the briefer I am away.

Since I work with electronics being charged can damage the things I am working with. So what I am doing at the moment is discharge myself anytime I return at my PC housing. This works, but it always causes flickering in my monitor and sometimes I have to replug my mouse to make it work again.

I know that most electronics have some kind of ESD protection built in, but that these get less and less effective the more they are used and will someday break. That is why I am worried about my equipment in the long term and would like a safer way to discharge myself.

I tried using the earth contact of the mains power outlet, but it hurts a lot more and the effect on my equipment seems to be even worse. I think it has to do with the fact that the PC housing is painted and therefore has a lot higher resistence.

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    \$\begingroup\$ is there a reason you can't use a standard ESD wrist strap? \$\endgroup\$ – Puffafish May 17 at 8:26
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    \$\begingroup\$ When I return to my desk, I ground myself on a conductor. There are an order of magnitude fewer nerve cells in the outside of a knuckle than the pad of a fingertip, so I lightly punch it, rather than use my finger. \$\endgroup\$ – Neil_UK May 17 at 12:44
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    \$\begingroup\$ The old school, though not entirely professional way, is to grab a radiator before touching electronics with your hands. (That is, the stuff that heats your building, not stuff that gives out radio waves. Silly English language.) \$\endgroup\$ – Lundin May 17 at 13:48
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    \$\begingroup\$ Dude, I had exactly this problem. The static was so significant, on one occasion I touched the backplate of a network card which instantly threw a network error on the computer's screen. The NIC refused to work again until the PC was rebooted. Vending machines would reboot themselves when I touched the coin slot. Turns out it was my shoes on the cheap synthetic carpet tiles at work; every time I walked to the kitchen I was "charging up" owing to friction. Google for "Antistatic Heel Grounder" or "ESD footwear". \$\endgroup\$ – Rab May 17 at 15:44
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    \$\begingroup\$ Some chairs have synthetic fabrics that build up a lot of charge when you sit down in / get up from them. \$\endgroup\$ – W5VO May 17 at 16:16

11 Answers 11

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The best way is to use an ESD strap, that is connected to earth via a 1MOhm resistor. This slowly but continuously discharges you without creating high currents. This way it does not hurt or damage anything.

But I also want to mention one "trick", when you dont want to use special equipment like an ESD strap. Discharging at the earth connection of mains works quite well, when you do not touch the contact directly but via an object you are holding in your hand (and that is at least slightly conductiv). I always get a big discharge when touching doorknobs at work, so I started to first touch the knob with my watch. This way the spark only exists between watch an knob, the current densitiy in my arm is already so low that I do not feel it any more. Or when getting out of car I already have the key in my hand - so I touch the door with the key first, before touching the metal directly.

But still - if your are regularyly working with electronics on your desk some basic ESD equipment would be the best solution. And I guess your boss will agree that the cost of an ESD strap is neglectable im comparison to failing electronics ;)

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  • \$\begingroup\$ Sounds like a great way to ruin a watch - unless it's a purely mechanical one. A watch with any kind of electronics in it might be killed by doing that... \$\endgroup\$ – Darrel Hoffman May 17 at 13:23
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    \$\begingroup\$ @DarrelHoffman No. A properly designed digital watch has to be able to withstand thousands of kV contact discharge to be put on market. Even more so through air discharge. So if your watch breaks from touching a door knob, it doesn't live up to for example the European EMC directive. \$\endgroup\$ – Lundin May 17 at 13:54
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    \$\begingroup\$ If you don't have a conductive object, using the back of your hand works well. The back of the hand isn't as innervated as the fingertips, so static shocks feel much less painful. \$\endgroup\$ – Wayne Conrad May 17 at 19:43
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    \$\begingroup\$ I think you do not feel the pain of discharge trough your watch because the area in contact with your skin is larger hence the amount of electricity passing through a single point is lower. In an open space office where the chairs were very prone to charging us we engaged in a spark war. My ultimate weapon was a metalic spoon. I felt nothing while discharging on my workmates neck/ears... ;-) \$\endgroup\$ – bokan May 17 at 22:44
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You can use a ESD mat, which is directly connected to the electrical ground. Just place it under your electronics and wear the connected bracelet when you are working with them. Touching the mat when you arrive at your desk would also discharge the static charge without affecting your PC.

ESD Mat

Image source

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  • \$\begingroup\$ Do these mats/bracelets have internal resistors? Or is it like touching the earth directly? \$\endgroup\$ – Karsten May 17 at 8:48
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    \$\begingroup\$ According to ANSI/ESD S4.1, the surface resistance has to be between 10^6 Ohm and 10^12 Ohm. A high-quality ESD mat would conform to these standards. \$\endgroup\$ – Bora May 17 at 9:07
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    \$\begingroup\$ @Karsten working with a hand connected 'hard' to safety ground would significantly increase the risk or electric shock (given some other fault condition). Therefore the mat must have redundant/fail safe internal resistance. \$\endgroup\$ – Sean Houlihane May 17 at 10:00
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    \$\begingroup\$ @Karsten it is worth noting that while "A high-quality ESD mat would conform" and "the mat must have redundant/fail safe internal resistance" you can still encounter low quality ones that do not. Thus, only buy from reputable sources, and it never hurts to measure resistance before first use. \$\endgroup\$ – Mołot May 17 at 13:35
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    \$\begingroup\$ @Karsten wrist straps usually come with a resistor to protect you when you accidentally touch a live connection when you are wearing the wristband \$\endgroup\$ – Ferrybig May 17 at 17:52
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The best conditions for static generation and discharge are;

  • dry air,
  • neoprene soled shoes
  • nylon seat cover,
  • nylon carpet.
  • and holding a metal key or pen to discharge to another metal object.

So reducing these effects comes from using;

  • leather shoes (sweat) or better,
  • ESD approved heel straps or best,
  • ESD shoes paid for by your employer ($)
  • with anti-static generating clothing
  • over weekly anti-stat sprayed carpet and chair
  • or better ESD approved materials
  • with an alternating polarity air ionizer
  • and raised humidity for extremely dry conditions.

I suspect it is the combinations of your shoes-carpet, clothes-chair with the friction that generate the triboelectric static.

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Carry around a 1MOhm resistor and touch one end to something grounded while holding the other end, or just get an ESD bracelet and wear it.

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  • \$\begingroup\$ But the ESD bracelet hat to be connected to something, doesn't it? When I leave my desk I would have to unplug it and replug it when I am coming back. Wouldn't that be almost the same as what I am doing now. As far as I know the bracelet does not prevent the collection of charge as long as it is not connected to anything. \$\endgroup\$ – Karsten May 17 at 8:29
  • \$\begingroup\$ Yeah, depending on your floor, there are also straps that go over your ankle and ground you to the floor, and you can always ground yourself to an ESD mat (which is a higher impedance path to ground which means less ESD and current) \$\endgroup\$ – Andrew Macrae May 17 at 8:38
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    \$\begingroup\$ The esd bracelet will dissipate the charge slowly so that you won't feel it. I say "slowly" but it is fast enough. You don't have to count to 20 or anything like that. You will be equipotential in less than a second. \$\endgroup\$ – mkeith May 19 at 3:14
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I have the same problem at my workplace where the floor is carpet. For some periods, I get several shocks a day touching metal doors, my laptop or sometimes the contacts of VGA or Ethernet cables.

I now carry around a resistor (600 kOhm but anything around 1 MOhm would be fine) and discharge myself through it before touching anything previously mentionned with my bare hands. This allows static charge to flow slower such that you won't feel it.

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While resistors and static mats are great for a professional electronics handler, I suspect most people would find carrying them around just for this purpose to be burdensome.

The resistors in the above systems slow the rate at which the current passes out of you reducing the shock. But you get the same effect by increasing the amount of skin in the circuit rather than decreasing the current flow.

I am unlikely to be without my key ring anytime I am likely to be touching electronics, so I take my key ring, hold it firmly to maximize skin area in electrical contact with the keys, and stick out the tip of one of the keys to touch the light switch-plate mounting screws as I enter the room. I make sure to press forward on the proffered key while doing this to insure it is in contact with the key ring itself and by extension all of my in-contact skin.

The screws are earthed through the switch itself and thus dissipate the potential, but without overly drawing it from one small spot of your skin, reducing the static shock to virtual insignificance. You could touch your mains outlet the same way.

In earlier times I always had a small pocket screwdriver clipped in my pocket that I used for the same thing which was even more convenient, albeit with less surface area, but they are difficult to find anymore and I have stopped carrying them.

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ESD pad and wristband are the correct solution when working at your desk.

When you are away from your desk, you can use ESD foot straps. They are inexpensive and can be bought from various vendors. As a DIY solution, you can try aluminum tape that goes from the inside of your shoe and around to the bottom.

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When there is no professional setup at hand and I still need to touch the circuit boards with my hands, I simply wash my hands in the bathroom before doing so. I believe the static is discharged through the running water into the ground.

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This is a fascinating discussion. I was always told that you can't earth static electricity charge you can only reduce its potential. This is why back in the 1960s on British roads you often saw people driving a car with a chain dangling from the rear bumper and usually it was dragging on the ground as the car went along which did nothing to reduce static. It was believed by many that removing static reduced car-sickness for affected passengers. But the proper way to deploy the chain was so that it almost reached the ground. My father used to hold the ignition key between thumb and first finger as he slid out of the seat (static generated by the seat of his pants) and he'd touch the key on the door frame as he stood up. This discharged the static from his body and it dissipated through the bodywork. A spark would visibly jump off the key as he touched the body. He also switched to leather soled shoes which helped compared to Neoprene soles.

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    \$\begingroup\$ Welcome to EE.SE, Larry. Please note that this isn't a forum of the type you may be used to and answers have to be actual answers and not a "discussion" as you seem to think. I think your answer has enough relevant material to stand as an answer. Please take the Tour to learn how the site works. Note that answers float up and down with voting or user sorting preference. One of my work colleagues solved the car static problem by letting his wife get out first! \$\endgroup\$ – Transistor May 18 at 10:29
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Take a habit of wearing ESD shoes at work. These slowly drain the charge as you walk, and if you're picking up the charge from the carpet, they prevent it from accumulating in the first place.

enter image description here

The main advantage is that once you put ESD shoes on, there's no protocol to follow. You can't forget to put a strip back on when you return to your desk, touch a metal object etc. You're really protected 100% of the time while walking freely around the office.

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Old school solution is to touch the grounded chassis first with one hand while using the other to handle sensitive devices. Never had a failure doing this.

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protected by W5VO May 20 at 14:56

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