ESD: Truths, myths, and flat out lies

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Well it's not my property, I'm just renting, but it's my understanding over here in spain, all electrical installations have to have safety measures and that one of them is that, so as to avoid electric shocks killing people, the current is grounded, in what they call ''toma de tierra''.

However, in Britain, I believe this works through a third prong, the ugly one that's added to what seems like the standard two rods in Europe.

Does the spanish version of ''toma de tierra'', which i assume is somewhere inside the walls, count for an ESD mat? Is it just as good as a British third rod and can I buy a british ESD mat and use an adapter to plug it into a spanish wall?
 

Mohonri

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If your electrical system doesn't have a ground, then the gas and water lines probably aren't grounded, either.
It's possible, I suppose, that they're not grounded. But if the water lines are copper pipes, and the pipe coming into the house is metal of some sort, it's grounded (since it goes through the ground outside). The same applies to your gas line, which is almost certainly grounded. (does any place allow non-metallic gas lines? I'm not 100% up to speed on recent building code changes).
 
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I'm not sure about connecting earth to a gas line or a water pipe, as I've read elsewhere that it's dangerous and puts the neighbours at risk.

I've also read there are ways to find out if it's grounded and I'll be looking up on that, but do you think plugging a British plug, through an adapter, would make a not-grounded house circuit electrocute me or at least burn the socket as there'd be some sort of confusion going on, or do these Earthing British 3rd pins, connected through through an adapter, also work on sockets that don't have the third pin?
 

Farva

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Do not put your ground to a gas line or hot water line. A nice spark will make things go boom.
 

mikeblas

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The misinformation in this thread just keeps coming. The NEC says, in section 250.52, that metal water pipes can be used for grounding electrodes in certain circumstances. That same section explains when pipes can't be used -- and that includes gas pipes. Most people think that gas pipes are good for grounding because they see wires at the meter or demarcation. But these conductors are for bonding, not grounding.
 

Mohonri

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Do not put your ground to a gas line or hot water line. A nice spark will make things go boom.
What's the point of a gas pipe if it doesn't keep the gas inside? You're not going to ignite an explosion by shuffling your feet across the carpet and then touching a gas line.

@mikeblas--I'm having trouble understanding how a gas line can't be grounded, seeing as it is buried. Unless it is thoroughly coated through its entire length with some sort of electrical insulation.
 

mikeblas

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I never said a gas line wasn't grounded; I said that the NEC says that the line can' t be used as a ground in an electrical system that will pass an inspection that looks for NEC code. In practice, a gas line might not be grounded because of the same reasons a water line wouldn't be grounded. One reason is that the line isn't buried deeply enough and for a long enough distance. Another reason is inadequate or failed bonding around insulators such as valves or in-line meters.
 

Mohonri

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I never said a gas line wasn't grounded; I said that the NEC says that the line can' t be used as a ground in an electrical system that will pass an inspection that looks for NEC code. In practice, a gas line might not be grounded because of the same reasons a water line wouldn't be grounded. One reason is that the line isn't buried deeply enough and for a long enough distance. Another reason is inadequate or failed bonding around insulators such as valves or in-line meters.
Ah, thanks for clarifying. For the purposes of working on a computer, then, as long as the gas or water line is grounded (even a little!), you're ok.
 

mikeblas

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Not really. If the pipe is energized at a high potential because of a fault elsewhere in the house, then equipment damage, personal injury, or death may occur.
 
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This is, after all, one of the top resources in google when it comes to ESD, whether we like it or not!

I really crazily want to ask, what happens if your power supply happens to not have an on/off switch? Isn't all the process of adding an antistatic wrist band to the case then rendered useless because there's no grounding going on? As far as I understand, you evidently cannot go about grounding yourself with the power supply actually on, as that would be dangerous, but you do want the case grounded, and the only way to ground the case is by connecting it to the house's grounded circuit.

And how does one use an antistatic mat? Do I put it under myself or under the case? And then connect the mat to a grounded house's circuit?
 

SarverSystems

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You'd put the mat on your work surface. The mat will have a grounding plug as well, which you can diasy chain to your wrist strap (plug your wrist strap into your mat, which plugs into the wall ground).

Ultimately you'd want a mat under your feet as well, but that would only be beneficial if you had static straps on your feet as well.
 
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You'd put the mat on your work surface. The mat will have a grounding plug as well, which you can diasy chain to your wrist strap (plug your wrist strap into your mat, which plugs into the wall ground).

Ultimately you'd want a mat under your feet as well, but that would only be beneficial if you had static straps on your feet as well.
Oh I see, the mat under the case (and all equipment), the mat connected to the grounded home circuit, would do just as well as a connected case.

Wouldn't rubber shoes be just as good for the feet?
 

DejaWiz

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Oh I see, the mat under the case (and all equipment), the mat connected to the grounded home circuit, would do just as well as a connected case.

Wouldn't rubber shoes be just as good for the feet?
No, since static can build up in your body just from the friction in your clothes, the rubber soles would insulate and prevent discharge to the floor. That's if you are not using proper grounding with a mat and wrist strap.

Point is, always use proper grounding and antistatic equipment since ESD is oftentimes unfelt, unheard, and unseen. It takes a very low amount of discharge voltage to damage ICs or traces, and more often than not the circuits will still function properly initially and for some time after, but the static damage can weaken the components which would lead to premature failure or simply unstable operation later on.
 

SarverSystems

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It takes a very low amount of discharge voltage to damage ICs or traces, and more often than not the circuits will still function properly initially and for some time after, but the static damage can weaken the components which would lead to premature failure or simply unstable operation later on.
AKA, the walking dead.
 
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No, since static can build up in your body just from the friction in your clothes, the rubber soles would insulate and prevent discharge to the floor. That's if you are not using proper grounding with a mat and wrist strap.

Point is, always use proper grounding and antistatic equipment since ESD is oftentimes unfelt, unheard, and unseen. It takes a very low amount of discharge voltage to damage ICs or traces, and more often than not the circuits will still function properly initially and for some time after, but the static damage can weaken the components which would lead to premature failure or simply unstable operation later on.
So, really, the claim that we're best off arranging desktop PCs when in the nude is not far off. Less friction of body with clothes, the better?

If I were to get worried and buy a second mat for my feet, are the antistatic wrist bands (or the bands sold with mats like the Lindy one) sold on amazon, long enough to go from my feet to the case on the table? I'm seeing they have these plasticky extensible character to them if you look close, I just don't know how extensible : http://www.youtube.com/watch?v=niRrYs_Js1s
 

DejaWiz

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AKA, the walking dead.
It amazes me how many people fail to get this concept when it's explained. For some reason, there are quite a lot of folks whom think ESD damage means not working at all. :rolleyes:

So, really, the claim that we're best off arranging desktop PCs when in the nude is not far off. Less friction of body with clothes, the better?

If I were to get worried and buy a second mat for my feet, are the antistatic wrist bands (or the bands sold with mats like the Lindy one) sold on amazon, long enough to go from my feet to the case on the table? I'm seeing they have these plasticky extensible character to them if you look close, I just don't know how extensible : http://www.youtube.com/watch?v=niRrYs_Js1s
You can buy specific static straps for your feet/shoes, as Sarver explained in an earlier post. I don't think it would be too wise to attempt modification of a wrist strap to function as a heel strap for standing on a grounding mat.
 
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If you touch the fridge, the cooker, or the washing machine and you don't get buzzed by a shock, is that enough to assume your house's ground is working OK?

I am being told to get a low voltage bulb and connect the neutral the earth in the wall socket through the pins in the bulb, and if the circuit of the house goes offline it means the ground is working well. I am also being told to do this with the live instead of the neutral.

I'm not so sure these things wouldn't mean I'd get electrocuted if there really is no earth in my house, so I'm kind of scared to go about doing that.

I've also read that inserting a multimeter or voltimeter's two pins into the live and the neutral and making sure the voltage difference shown on the voltimeter is as close as possible to 0V, is the way to check whether or not there is a ground in the house.

I have also come to understand that using a voltimeter or a bulb only give vague impression of what the earth is like, and that they'll tell me whether or not the earth exists, but to measure more accurately an earth penetration tester is required but these things cost hundreds of euros so I'm trying to avoid that. I'm also trying to avoid having to bring in an electrician as that'll also cost hundreds.

So what do you guys think?

It's kind of a rabbit hole all this, wanting to set up a desktop PC, spend ages researching the parts required, then spend ages about earthing and now having to learn which way to check I even have earth. But hopefully I'm getting there...
 
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You can buy specific static straps for your feet/shoes, as Sarver explained in an earlier post. I don't think it would be too wise to attempt modification of a wrist strap to function as a heel strap for standing on a grounding mat.
Wouldn't the heel and feet be on a mat, and wouldn't the mat be connected to the house's earthed network? I mean, don't these mats come with plugs to attach them to the wall, or are they not good enough because the heels are probably below the wall socket?
 

DejaWiz

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Wouldn't the heel and feet be on a mat, and wouldn't the mat be connected to the house's earthed network? I mean, don't these mats come with plugs to attach them to the wall, or are they not good enough because the heels are probably below the wall socket?
Positioning of the wall socket has nothing to do with it. The wall socket could be in a different room or building/house altogether as long as the connection is good.

The purpose of the mat is to have a place for the static discharge to go with little chance of failure because of the large surface are... think of it like the drain in a toilet. Now the purpose of a heel strap is to draw the static electricity out of the body and direct it to the mat...think of it like a steady directed stream of urine, instead of a sudden discharge into whatever electrical circuit is being physically handled...think of that as explosive diarrhea. :D
 

kinglerch

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It amazes me how many people fail to get this concept when it's explained. For some reason, there are quite a lot of folks whom think ESD damage means not working at all. :rolleyes:.
It amazes me how many people buy into ESD, something you can't see, hear, or touch, something that may or may not break something a little or a lot, and something that no one can ever tell you the chance of it even happening.

Keep buying straps and equipment to keep the ESD gnomes away. You can also buy flood insurance in Arizona, but at least you can know the chances of a flood and when it actually occurs.

ESD is a convenient target when something stops working, was designed wrong, etc. Oh if only I worked on it naked and strapped my schlong to the floor, it wouldn't have broken. :rolleyes:

I have a standing offer for anyone who believes in ESD. I will take a PCB of your choice, wear fuzzy slippers and a sweater in a dry room, and handle the card all day long....rubbing my feet on the carpet, trying desperately to get some sort of static shock onto this card. I will then take any bet that the card has nothing measurably wrong with it.
 

LigTasm

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Uninformed stuff
Your lack of knowledge does not preclude something from existing. You can see the damage to semiconductors under a microscope, and typically the failure modes will be during certain operation and temperature. Companies spends millions of dollars analyzing and tracking ESD failures for warranty purposes. Its not that the component usually fails completely, but more of a question of how long it will work and under what conditions.

I have presentation slides on the topic, however I can't upload them from the computer at work. I will try and post them from home later tonight.
 

mikeblas

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I have a standing offer for anyone who believes in ESD. I will take a PCB of your choice, wear fuzzy slippers and a sweater in a dry room, and handle the card all day long....rubbing my feet on the carpet, trying desperately to get some sort of static shock onto this card. I will then take any bet that the card has nothing measurably wrong with it.
Are you an engineer?
 

kinglerch

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Yes I am an engineer (electrical) for 20 years. I am not saying ESD cannot exist. I am only saying that the precautions taken for a thing such as this are astounding, while the risks are blown out of proportion.

I have seen a room made entirely of copper...this is true. They even had a cutout in the wall where you could see the copper material. I have seen other rooms with no ground whatsoever, the entire room was floating (potential)...all in the name of ESD.

There are entire industries dedicated to ESD (bags, straps, labels, tables, etc) yet no one can tell us the risk involved (chance of damage happening) nor the risk mitigation by using one of the devices. Please tell me one other industry where this is true! Medicine? Insurance? UFOs? If I sold a product to prevent something from happening, yet I couldn't tell you the chance of it happening either with or without my product, you would never buy the thing.

I have even seen boards fail when no one touched it at all. It worked, we cycled power, and then it didn't work. Bad board design? Bad IC? It is extremely convenient to blame ESD, and say that if I had only worn more straps the board would have been fine.
 

Justintoxicated

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I usually leave the AC on during a dry summer day, then I rub my feet across carpet with shoes on and only then put my PC together :)

Ok, but really, my case isn't gounded, my PSU isn't grounded, so when I build a PC I just try to touch something metal before I begin.

Most of my outlets are not grounded either, only the kitchen and a couple in the garage, so none of my PCs are grounded. All the houses I have lived in over the last 20 years have not had grounded outlets, and only one had an issue which seemed to stem from cables being connected to a cable box. Apparently the Cable from the cable company at the time was grounded so energy was flowing to that, and could give you a very mild shock if you were touching the PC case.
 
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mikeblas

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That thread is full of the same "never seen any problems" idiocy we've had here.
 

Reaver9

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Hey guys, I have one question and I think here's the right place to ask. Holding the graphics card by the sides of the pcb (not touching any component), offers any risk of esd? I guess no, even backplatted GPUs have the sides unprotected. What do you guys think? Thanks
 

cyclone3d

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Hey guys, I have one question and I think here's the right place to ask. Holding the graphics card by the sides of the pcb (not touching any component), offers any risk of esd? I guess no, even backplatted GPUs have the sides unprotected. What do you guys think? Thanks
Static can jump. So if you are really charged up and then touch a card, even on the edges, the static could jump an inch or more..

Try it with a balloon or laundry from the dryer in the dark sometime. The length that the static can jump is quite impressive.

That being said, just touch something that is grounded first to discharge yourself.

No point in being paranoid about it.
 

Reaver9

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@cyclone3d thanks man! I'm a little worried, because my GPU arrived first and I was so anxious thats I completely forgot about this and opened the box, only holded by the sides, buuuuut like you said, got a little paranoid about it. I don't think I was charged up and ruined something, but now only time will tell =|
 

dr/owned

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Yes I am an engineer (electrical) for 20 years. I am not saying ESD cannot exist. I am only saying that the precautions taken for a thing such as this are astounding, while the risks are blown out of proportion.

I have seen a room made entirely of copper...this is true. They even had a cutout in the wall where you could see the copper material. I have seen other rooms with no ground whatsoever, the entire room was floating (potential)...all in the name of ESD.

There are entire industries dedicated to ESD (bags, straps, labels, tables, etc) yet no one can tell us the risk involved (chance of damage happening) nor the risk mitigation by using one of the devices. Please tell me one other industry where this is true! Medicine? Insurance? UFOs? If I sold a product to prevent something from happening, yet I couldn't tell you the chance of it happening either with or without my product, you would never buy the thing.

I have even seen boards fail when no one touched it at all. It worked, we cycled power, and then it didn't work. Bad board design? Bad IC? It is extremely convenient to blame ESD, and say that if I had only worn more straps the board would have been fine.
:rolleyes:

Here's a topic about Ebay sellers being too sloppy with GPUs and other parts. Interesting to see that it has been heavily downvoted.

http://slickdeals.net/f/6992624-avo...t-for-motherboards-and-other-electronic-items
I once had a guy message me on ebay and try to bitch me out about the fact that I was shipping RAM wrapped in aluminum foil. Noob doesn't know that shorting all pins via aluminum foil is an acceptable way to transport ICs.

Hey guys, I have one question and I think here's the right place to ask. Holding the graphics card by the sides of the pcb (not touching any component), offers any risk of esd? I guess no, even backplatted GPUs have the sides unprotected. What do you guys think? Thanks
Probably acceptable.
 

workshop35

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Water pipes are actually often a good ground as well. Often times if you go into indsutrial areas there are grounds tied to them.

and if you decide to ground yourself or a component to something, always connect the ground wire to the component first then to the ground if possible
 

mikeblas

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If you want a ground point, your best bet is an electrical ground. (I would've thought that obvious.)
 

Nobu

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and if you decide to ground yourself or a component to something, always connect the ground wire to the component first then to the ground if possible
If you're wearing a grounding strap (connected to ground), then it's better to ground yourself first, then touch the component, because the grounding strap has a resistor that limits the flow of current to an acceptable rate (iow, it prevents the voltage from discharging all at once). Since the current has to flow through the grounding strap to reach ground, it's less likely to cause damage. This is, of course, assuming you are properly insulated from other paths to ground--if there's a way to get past that resistor, then your grounding strap is about useless.

If you're not wearing a grounding strap, then your guess is as good as (or better than) mine. ;)
 

workshop35

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If you want a ground point, your best bet is an electrical ground. (I would've thought that obvious.)
many times electrical grounds in old homes (2 prong outlets) are tied to water pipes when they are upgraded to outlets with a ground. I'm not saying its perfect but its an option depending on your situation.
 

workshop35

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If you're wearing a grounding strap (connected to ground), then it's better to ground yourself first, then touch the component, because the grounding strap has a resistor that limits the flow of current to an acceptable rate (iow, it prevents the voltage from discharging all at once). Since the current has to flow through the grounding strap to reach ground, it's less likely to cause damage.
yeah I think I wrote that oddly, it doesnt make sense to touch a component then ground yourself. Kinda defeats the purpose. But if you are grounding a component you want the potential to equalize away from the component, which is why you'd attach your ground wire to the component first then to ground.
 

DejaWiz

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^ that won't make any difference. Manufacturers assembly lines and work stations are grounded, then the components are brought in. So effectively, they attach to ground first, then the component is grounded after that.
 

workshop35

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Manufacturers workstations and the like are going to have grounding similar to a wrist strap where they use a resistor to limit current flow. If you are connecting directly to ground you want the qualization of potential to be away from the component especially if what you are grounding is explosive.
 
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