Ground yourself - do you bother?

Stephen

I ground myself as in touch a steel surface in the case and so on, but I never bother with wrist straps or any of that tat.

Anti

Stephen wrote:

I ground myself as in touch a steel surface in the case and so on, but I never bother with wrist straps or any of that tat.

Wriststraps r 4 feags

mathias

As I have posted before I work in the industry , specifically test , and the amount of ESD troubleshooting teams I have had to join has increased in the last number of years due to the shrinking geometry of the fab process , you guys are currently buying 90nm chips , we are currently producing 45nm chips , this hugely increases their sensitivity to ESD damage,

The following quote is taken from here ,

http://www.broadbandreports.com/faq/hard/2.1_Build_Where_to_Buy ,

Why use Electro Static Discharge straps (#1731)

Taken from the A+ Certification book by Michael Meyers.

Typical Electrostatic Voltages-

Humans can accumulate electrical potentials well over 25,000 volts. Although we might experience a shock or other sensation when the charge dissipates, it is a very quick, low-current flow that is not harmful. But as little as 30 volts can destroy some of today's more sophisticated integrated chips, so daily activities can generate static charges on your body that are potentially harmful to sensitive electronic components.

Consider the following:

Walking across carpet: 1,500 to 25,000 volts
Walking over an untreated vinyl floor: 250 to 12,000 volts
Picking up a common plastic bag: 1,200 to 20,000 volts
Working at a bench: 700 to 6,000 volts
Handling a vinyl envelope: 600 to 7,000 volts.

Costly Effects of ESD

An ESD must reach a minimum of 3,000 volts of electricity before most people notice the shock. Although most of us feel an ESD of 3,000 volts, we fail to feel smaller charges, and yet these charges still damage semiconductor devices. Many of the CMOS technology components can be destroyed by less than 1,000 volts.

Technology continues to advance, making smaller, more closely packed components. The microscopic spacing of insulators and circuits within chips is increasing the sensitivity to ESD. Proper ESD protection is a must!

Types of ESD Damage

The damage caused by ESD takes on three forms: upset failures, latent catastrophic failures, and direct catastrophic failures.

Upset failures occur when a small ESD causes minor gate leakage. Upset failures are intermittent in nature. This type of damage might not be detected by quality control or end-user test programs, but it shows up as an unexplained loss of data. These ESD cause the most embarrassment to technicians because mishandling parts tends to create this type of error. The embarrassment manifests itself as repeated calls, or worst yet, installing a device such as extra RAM. The RAM takes an upset failure and displays random-memory errors during POST. Who was the last person to touch the system? You! "Everything was fine until you touched it!" Sound familiar?

Latent catastrophic failures occur when the ESD damage causes the transistor junction to weaken; we like to call these zings. This transistor might pass all tests, but over time will react with poorer system performance and eventual system lockups. Because latent failures show up well after installation, the cause of these lockups seems "unknown," and the cost to troubleshoot and repair usually makes system replacement worthwhile.

Direct catastrophic failures, known as zaps, usually occur with ESD shocks of more than 3,000 volts. The device that takes the shock fails completely, and you must replace the part. The obvious failure makes zaps the easiest to find, as diagnosis tends to point quickly to the failed device.

Pages 366-368 in the 2001 revision
As posted by YIN

JTMO- Wrist straps are only a few dollars at the local electronics store. Use them and save yourself some grief later on.

In short , there is a very good reason why the likes of Komplett now include a static wrist strap with their upgrade packs , it takes seconds to clip yourself to a radiator , and can save you weeks of RMA hell , so do it lads !!

DaSilva

25000 Volts in a person? Rofl I really am having a hard time believing that figure.

Grounding is basically just touching a good large conductor.

ESD damage is most likely going to occur to hardware if you have built up a lot of static, and you touch some of the sensitive areas on hardware, such as pins, transistors, etc...

If your holding hardware by the edges (the green parts [ok well I'm colour blind i think its green], not the shiny bits) or by plastic parts then you are very unlikely to discharge any notable current, simply because these parts are good insulators. Unless your charged like a feckin Tesla coil, but if that's the case I'd be more worried for my health than the hardware.

Touching anything big and metal will most likely discharge you a huge amount, and you can begin work, unless you think you are going to build up a huge charge again. I think those static wrist things are the biggest gimmick ever.

Or wait, I'm gonna patent the solid silver wrist ground wire, cause you know those ones they use currently are probably copper or maybe even aluminium and frankly when it comes to conductors they just won't cut it.

mathias

Assuming you are serious and not trolling of course , and for the benefit of the 1 or 2 that might believe you ,

25000 Volts in a person? Rofl I really am having a hard time believing that figure.

Yes , easily , you need to learn some electrostatics , you seem to be mistaking current electricity for static electricity or electrostatics ,
Read this ,

http://www.esda.org/documents/esdfunds1print.pdf

If your holding hardware by the edges (the green parts [ok well I'm colour blind i think its green], not the shiny bits) or by plastic parts then you are very unlikely to discharge any notable current, simply because these parts are good insulators.

Not so , ever heard of Field induction , or more specifically regarding chips , the field induced charged device model ,

http://ieeexplore.ieee.org/iel5/4126/18727/00865120.pdf?arnumber=865120

The package gets charged , package is usually plastic , the charge is induced to the die by field induction and can discharge then through the pins ,
50V , a very small amount of charging in triboelectric terms , is enough to damage a modern integrated circuit.

Grounding is basically just touching a good large conductor.

Not unless the large conductor is itself grounded ! , again learn some electrostatics !! Basic Junior cert stuff !!

Heres a paper showing projected device sensitivities for ESD from 2004 out to 2010 , Field induced charge device model being the number one concern as it has the lowest damage threshold , 50v , thats static charge of course , you can generate that by blowing a kiss at someone !!

http://www.esda.org/documents/ElectrostaticDischargeRoadmap-March42004Final_061405edits_000.pdf

Or wait, I'm gonna patent the solid silver wrist ground wire, cause you know those ones they use currently are probably copper or maybe even aluminium and frankly when it comes to conductors they just won't cut it.

Funny man ,

Of course " grounding " wrist straps are described as "grounding" straps in terms of ESD only , naturally the operator is not expected to be directly connected to ground , that would be a major health hazard , no , the strap has a 1 megaohm resistor connected in series. This is adequate to quickly and safely dissipate any charge on a device or on the person while still keeping the builder safe ! So its ground for ESD and nothing else if you know what I mean !

The Dissipative range for ESD is between 1 x 10^6 Ohms to 1 x 10^9 Ohms, there are various materials that can manage this including treated carpets , tiles , shoe leather , smocks , polymers such as Torlon , Semitron , etc.
It does not necessarily have to be metal or wire. Indeed there are various worktops, shoes , and mats that can be used instead of wire.

This is one of the reasons why its safer and better to use the strap , touching yourself off the PC case only dissipates charge if the case is left plugged in , and that provides a potential electrocution hazard for the builder should the power be accidentally left on and the PSU is faulty, the strap on the other hand , has a safe resistance built in that dissipates the charge
while restricting any dangerous currents for the builder , do the ohms law calculation , even touching the mains with the wriststrap on limits current to approx 240 microamps.
Therefore , using the strap , you can safely disconnect the case from the mains, and clip the strap to a ground point , the most common home ground point is a radiator , the back part thats not painted of course.

The strap is the cheapest by far too , so the "gimmick" is this 2-3 euro wrist-strap that most parts manufacturers would gladly give you for free to stop you bringing back blown parts , rather than try to sell you the much more expensive shoes , smocks , tables , mats , etc. Some Gimmick !!