Ripley's build it or not! (Big pictures)

[olds442]

https://www.youtube.com/watch?v=cGg0yUTgT_M
Please watch that video.


ESD mats prevent static build up in the first place, but can also can be grounded to act like a wrist strap.

[SilverZ06]

This is all over blown. I assemble my PCs with my socked feet resting on a running treadmill with a carpeted belt. No issues.
YMMV.

[Chalenge]

To be totally fair the wrist grounding method is the best way to go. You cannot always be sure that electrical ground is always earth ground. That is you should work with the PSU unplugged from the wall. In your part of the world earth ground might always be the same as electrical ground, but I wouldn't count on it. In France, for instance, there may be several miles between the house and the substation where neutral is actually grounded. In that case there may be a few volts present on neutral and in that case you do not want the PSU plugged in when you interact during a build.

[Bizman]

IMO there's many more variables to take into account here than just the strap, mat and sweaty arm that have been mentioned. One factor is that here in Finland we don't use wall-to-wall carpet very much which reduces static charges quite efficiently. Clothing is another factor, wearing an acrylic pullover on a polyester shirt is prone to cause sparks.

I once visited a factory where static electricity was strictly prohibited. They had ESD mats all over the floors around their work benches, everyone moving around there had to take care their shoe soles and clothes fulfilled the specs etc. Definitely something else than a budding PC builder unwrapping his gear on a thick living room carpet wearing woven clothes during the driest winter.

[olds442]

To be totally fair the wrist grounding method is the best way to go. You cannot always be sure that electrical ground is always earth ground. That is you should work with the PSU unplugged from the wall. In your part of the world earth ground might always be the same as electrical ground, but I wouldn't count on it. In France, for instance, there may be several miles between the house and the substation where neutral is actually grounded. In that case there may be a few volts present on neutral and in that case you do not want the PSU plugged in when you interact during a build.

You do know that ground and neutral are different right? Ground is a pole that goes 13ft down at your own house. Neutral is grounded at the power lines.

[Chalenge]

Yes, and that is consistent with what I posted.

[MrRiplEy[H]]

Old buildings may have problems with grounding. For example when I bought my house which is built in 1945 it didn't have a grounding loop at the main switch box at all. We naturally installed one when we renewed the electric systems of the house. Required digging a 9 meter long 1 meter deep hole on the back yard and sinking a copper cable in it.


It seems some of you guys have blown the safety requirements completely out of proportions. If you don't have a grounded ESD mat under you, you're just as safe touching the case manually than you would be with a wrist band connected to the case. Working at a factory professionally under ESD protection is one thing and working at home building your home pc is another.


I guess you all buy a 3 grand 4-point car lift, oil suction pumps with a 10 gallon tank, professional tool sets, seat covers, overalls, 3 grand STAR analyzer etc. for your home garage when doing chores on your car? I mean no professional will touch the car without those. Me, I'm satisfied with my 25 dollar OBD II reader to check the occasional fault code. Works for me.

[MrRiplEy[H]]

.
2: ESD mats are to prevent electrostatic build up, not stop it from discharging. To stop discharges you need a faraday cage, aka anti static bag that all of your parts come out of the box with.


Its very possible you could work on PCs all your life and with no safety for ESD and not damage one part. Its also possible to go in a swimming pool during a lightning storm and never get hit by lightning.

ESD mats work only if you ground them. Their whole idea is to be made out of a conductive material that grounds YOU and dissipates any static buildup you may have. An ungrounded ESD mat on top of a static charged room carpeting is fully static just as any other material would be.


But if using one makes you feel better, go ahead

[olds442]

ESD mats work only if you ground them. Their whole idea is to be made out of a conductive material that grounds YOU and dissipates any static buildup you may have. An ungrounded ESD mat on top of a static charged room carpeting is fully static just as any other material would be.


But if using one makes you feel better, go ahead

So rubber is a conductive material? And as its been pointed out to you many times, touching the case is only effective if you hold the case and not just touch it

[MrRiplEy[H]]

So rubber is a conductive material? And as its been pointed out to you many times, touching the case is only effective if you hold the case and not just touch it

Yes, rubber can be made very conductive if need be. In case of static electricity it's preferable to have a low conductivity to safely dissipate any static buildup. You also don't want a situation where your right hand touches live mains and your left hand is free current flow connected to the ground. That would instantly electrocute you. That's why your average wrist band also has a 1Mohm resistor attached to it. If your rubber mat would be an insulator, you'd be creating a big static potential just like when you walk on vinyl flooring or plastic carpeting.


http://hollandshielding.com/93-Electrically_conductive_rubber?gclid=CI70m8Oi7sMCFcQCcwodc7sA8Q


What did you think the ground lead in the ESD mat was for? 


When I assemble my computer I firstly never hold it upgright on its feet but lay it down on its side. Then when I install the components, I support my elbows to the sides of the case so whenever I install a new component or touch an existing one, I'm in contact with the case. Also most devices are largely protected so if you refrain from touching the metal connectors while installing your chances of ESD damage are greatly reduced.

Seriously, if ESD was that big of a practical problem you make it to be I'd have at least one component damaged during installation by now. On older computer parts I've ripped parts off and yanked new (used) ones in very carelessly and not one time I experienced problems. However if I was wearing clothes that made me shock door handles, faucets etc. regularly, I'd probably choose not to touch the innards of a computer under those conditions

[Bizman]

When I was studying computing we also had some PC building lessons. Our teacher told about wrist bands, but said that he never uses one. Sweaty arms leaning against the case would do the trick was his opinion. He also told about leaving the PSU plugged into mains for grounding, only switching it off - unless there was no switch in which case the computer had to be unplugged. So that's how we took apart and rebuilt the computer in the classroom - on a standard table without any ESD mats or anything. During that year we also had personal hard disks which we swapped for every lesson. None of the computers broke because of a zap.

The same guy successfully managed to hot-swap a bios chip after a failed flashing.

A long time ago I once managed to zap one component. I was doing the building on our living room rug which had proven to charge people very effectively if they dragged their wool socks on it...

[olds442]

Yes, rubber can be made very conductive if need be. In case of static electricity it's preferable to have a low conductivity to safely dissipate any static buildup. You also don't want a situation where your right hand touches live mains and your left hand is free current flow connected to the ground. That would instantly electrocute you. That's why your average wrist band also has a 1Mohm resistor attached to it. If your rubber mat would be an insulator, you'd be creating a big static potential just like when you walk on vinyl flooring or plastic carpeting.


http://hollandshielding.com/93-Electrically_conductive_rubber?gclid=CI70m8Oi7sMCFcQCcwodc7sA8Q


What did you think the ground lead in the ESD mat was for? 


When I assemble my computer I firstly never hold it upgright on its feet but lay it down on its side. Then when I install the components, I support my elbows to the sides of the case so whenever I install a new component or touch an existing one, I'm in contact with the case. Also most devices are largely protected so if you refrain from touching the metal connectors while installing your chances of ESD damage are greatly reduced.

Seriously, if ESD was that big of a practical problem you make it to be I'd have at least one component damaged during installation by now. On older computer parts I've ripped parts off and yanked new (used) ones in very carelessly and not one time I experienced problems. However if I was wearing clothes that made me shock door handles, faucets etc. regularly, I'd probably choose not to touch the innards of a computer under those conditions

http://electronics.stackexchange.com/questions/19262/how-to-know-that-i-am-grounded-with-an-anti-static-wrist-strap

also you seem to keep forgetting that I never said you needed an ESD mat or any ESD protection at all. Modern components have protection circuits in the form of internal diodes from - to +.

Also, that 1mOhm resistor is to stop any painful discharge and discharge your body slowly.

[MrRiplEy[H]]

http://electronics.stackexchange.com/questions/19262/how-to-know-that-i-am-grounded-with-an-anti-static-wrist-strap

also you seem to keep forgetting that I never said you needed an ESD mat or any ESD protection at all. Modern components have protection circuits in the form of internal diodes from - to +.

Also, that 1mOhm resistor is to stop any painful discharge and discharge your body slowly.

The resistor is to stop any painful death in case your other hand happens to touch 120V/240V. Also the resistor limits currents if your grounded body touches a staticly charged object. Current damages, not voltage.

The rule of thumb any electrician is taught at school is to keep your other hand in your pocket when examining live circuits. Electricity can do no harm as long as it has nowhere to go - the current must always flow somewhere. In case of static it gets a bit tricky because two floating objects can still zap eachothers if they have differently charged potentials. That's why joining the objects through your body will even up their potential to the same level using your skin as a resistor.

If your installation target is grounded that always creates the maximum possible potential difference so without a high value resistor you could kill your component wearing a wrist wrap if the component was placed on a highly static floor rug for example. The static of the rug would dissipate explosively through you when you touch the component. The resistor limits the current to a safe level in addition to protecting your life.

But again, if the case is floating, touching it will even up any potential difference your body and the case has. Once there's no potential difference no ESD can happen. And your repeated posting about 'it's no capacitor' is not valid. You're not a capacitor either but you still build up static.

I have nothing against people buying the anti-static wraps naturally as long as they know how to use them and follow the other basic safety guidelines.

[olds442]

The resistor is to stop any painful death in case your other hand happens to touch 120V/240V. Also the resistor limits currents if your grounded body touches a staticly charged object. Current damages, not voltage.

The rule of thumb any electrician is taught at school is to keep your other hand in your pocket when examining live circuits. Electricity can do no harm as long as it has nowhere to go - the current must always flow somewhere. In case of static it gets a bit tricky because two floating objects can still zap eachothers if they have differently charged potentials. That's why joining the objects through your body will even up their potential to the same level using your skin as a resistor.

If your installation target is grounded that always creates the maximum possible potential difference so without a high value resistor you could kill your component wearing a wrist wrap if the component was placed on a highly static floor rug for example. The static of the rug would dissipate explosively through you when you touch the component. The resistor limits the current to a safe level in addition to protecting your life.

But again, if the case is floating, touching it will even up any potential difference your body and the case has. Once there's no potential difference no ESD can happen. And your repeated posting about 'it's no capacitor' is not valid. You're not a capacitor either but you still build up static.

I have nothing against people buying the anti-static wraps naturally as long as they know how to use them and follow the other basic safety guidelines.

http://en.wikipedia.org/wiki/Body_capacitance

also, saying "its not the voltage that kills, its the current" is the most dangerous thing to tell anyone.
https://www.youtube.com/watch?v=8xONZcBJh5A

[ebfd11]

OLDS can you at least say this is an informative post by Ripley and agree he did a good job.

LawnDart