Timeline for Do antistatic gloves help avoiding ESD?
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23 events
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| Jul 15, 2017 at 4:59 | comment | added | Neil_UK | 'dry hair is not a good conductor' is one of those 'true but irrelevant' statements. Charge is able to build up on a conductor with respect to another conductor, if, and only if, it's insulated from that other conductor. It doesn't matter whether the person is bald or hirsute, unless of course they are using the grounding strap like a bandana, insulating remote parts of the conductor surface make no difference. When it comes to laws, those for social convention (which parts of the body to cover) and those for physics (use conductive or insulating stuff for covering) have different status. | |
| Jul 14, 2017 at 20:53 | comment | added | Jack Creasey | @inf3rno. To allow charge build-up you don't need a good conductor. What you need is a very high resistance, which dry hair does have. I guess we should move static sensitive industries to areas that have nudist colonies ....that may help. | |
| Jul 14, 2017 at 16:54 | comment | added | inf3rno | @JackCreasey So we should be nude by repairing computers. :D I think dry hair is not a good conductor, so charges can build up on your head. Lol, I just read the comments, somebody serioously did this? :D | |
| Jul 14, 2017 at 5:18 | comment | added | Neil_UK | @JackCreasey that's introducing unneccessary assumptions. We had one engineer who used to work naked, until an unfortunate solder-splash. You don't need conductove clothes, that's why the wrist band connects to bare skin, rather than over your sleeve. But if you cover your hands with gloves, and if you touch things that you want to stay at your potential as a result of your touch, then they should be conductve. | |
| Jul 14, 2017 at 5:10 | comment | added | Jack Creasey | @Neil_UK. I meant that you likely want to be clothed ....and they need to be conductive. | |
| Jul 14, 2017 at 5:09 | comment | added | Neil_UK | @JackCreasey There is no need to coat the body in conductor, the body is a conductor. When insulated from another condcutor, like ground, a body can develop a voltage with respect to that conductor, another way of saying it holds a charge with respect to that conductor. Connect it to that conductor, and a charge flows to equalise their voltages. Once connected to that conductor, it does not hold a charge with respect to it. The purpose of stndard ESD practice is to connect all things, so things don't build up different voltages, aka different charges, with respect to each other. | |
| Jul 14, 2017 at 4:52 | comment | added | Jack Creasey | @Neil_UK. With that comment I agree. So you must also agree that the objective is to coat the body in conductive (relatively) materials and provide a contact from the body (a bulk resistor) to workstation ground. The only point that is somewhat difficult is hair (dry hair will hold a charge) and for this you wear a conductive net to at least reduce movement and limit static build up. I have not changed my story since the beginning of the thread ....the body is a bulk resistor and won't hold a charge. | |
| Jul 14, 2017 at 4:39 | comment | added | Neil_UK | @JackCreasey Unless you're working free floating in space, other materials are always involved. Of course the body does not have a charge in isolation, it's with respect to things like floor, benchtop, the mobo you don't want to trash. As you point out, the body is relatively conductive, so that's where the charge builds up. In bare feet on a conductive floor, no charge accumulates with respect to the floor conductor. With plastic-soled shoes, yes it would. Dry clothing is relatively insulating. | |
| Jul 14, 2017 at 4:33 | comment | added | Neil_UK | @inf3rno to fit a mobo to a case, I (a) get a clear working environment (b) clip myself to the target PC case (c) get hold of the outside of the conductive mobo bag with bare hands which brings it to same potential (d) open bag, reach in, and take hold of mobo by a groundy conductor, so connector shell or solder ring round a screw-hole (e) place mobo in case, line up screw holes, and get one screw in so mobo gnd is attached to case ground (f) put rest of screws in trying not to smash components with screwdriver. | |
| Jul 14, 2017 at 4:29 | comment | added | Neil_UK | @inf3rno a screwdriver tends to come into contact with screws, which go into grounded parts of the chassis, so usually low risk. Smashing the board or components with them is a problem. Connector block screws, being intended for external connection, tend to be well protected electrically, so screwdrivers rarely cause a problem. However, a conductive handle keeps them at your potential, so removes any static problem they might have had if you do smash components with them. | |
| Jul 14, 2017 at 4:12 | comment | added | Jack Creasey | @inf3rno. en.wikipedia.org/wiki/Electric_shock The body (even with a very dry epidermis layer) is unlikely to present much more than 200k Ohm resistance. This makes the body simply a big resistor (internally it's down to 1k Ohm or so). The static charge builds up on the clothes and wrapping on the body. I agree with Neil the objective is to keep everything at the same potential and grounded. However any text materials indicating the the human body can accumulate a charge (without other material involved is misplaced. | |
| Jul 14, 2017 at 2:43 | comment | added | inf3rno | @Neil_UK Am I right that a magnetic screw driver does not do any damage? I guess the handle should be made of a conducting material (metal) instead of rubber. | |
| Jul 14, 2017 at 2:32 | comment | added | inf3rno | @Neil_UK Do you need to use special screwdriver to avoid ESD? What precautions do you do by taking out for example a motherboard from an ESD protected bag? | |
| Jul 14, 2017 at 2:24 | comment | added | inf3rno | @JackCreasey en.wikipedia.org/wiki/Static_electricity | |
| Feb 25, 2017 at 14:51 | vote | accept | CommunityBot | ||
| Jan 7, 2017 at 11:49 | history | edited | Neil_UK | CC BY-SA 3.0 |
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| Jan 7, 2017 at 9:08 | comment | added | Neil_UK | @JackCreasey I've updated my answer with a bit more information, and background. Look up tribolectric charging for the walking on a carpet issue. Look up the many Q/As on this site for ESD protection, unfortunately some still contain a lot of rubbish. The central principle is keep everything at the same potential, everything, without exception, everything. If it achieves that consistently, then it's good. The difficulty is coming up with a system that poorly trained people can use consistently. | |
| Jan 7, 2017 at 9:03 | history | edited | Neil_UK | CC BY-SA 3.0 |
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| Jan 7, 2017 at 7:16 | comment | added | Neil_UK | @JackCreasey Sounds like you need to take electronics 101. Pleas stop posting rubbish. It's difficult enough to get people to understand how to take ESD precautions, without you doing a Trump on them. If the carpet fibres get one charge, where does the opposite charge accumulate? | |
| Jan 6, 2017 at 22:55 | comment | added | Jack Creasey | Double Duh. You being at a different potential does not mean you have accumulated a charge....it means you are attached to material which can sustain the voltage (across the capacitor) and which holds the accumulated charge. The body is just a bulk resistor in the main. Try walking naked over synthetic carpet and let me know the results? You will not accumulate charge, but charge will accumulate on the carpet fibers. electrostatics.com/page2.html Yes, grounding the human body reduces hards.....by reducing the provision of a path to the high voltage capacitive materials. | |
| Jan 6, 2017 at 20:30 | comment | added | Neil_UK | You earth yourself through a contact to station ground to keep yourself at the same potential as station ground. You being at a different potential from station ground ===> you have accumulated a charge with respect to station ground. Duh! Try walking across a synthetic carpet in insulating shoes, then lick a filing cabinet. That belt you get is the charge you've accumulated jumping from your tongue to the filing cabinet. | |
| Jan 6, 2017 at 17:34 | comment | added | Jack Creasey | 'You' don't accumulate or retain a charge at all, that is pure mythology. 'You' are too wet and low resistance to retain or support a charge. Charge is accumulated on clothing/footwear, 'You' are just a resistive pointer to complete the circuit, that is why they earth you through a contact to station ground. Wearing antistatic cloves provides a consistent global R value for the skin (though it also helps prevent oils transfer from the skin). | |
| Jan 6, 2017 at 17:23 | history | answered | Neil_UK | CC BY-SA 3.0 |