I’m about to start building my new computer, I needed some tools so I picked up a kit which happened to have an anti-static bracelet. I’ve never used one before but I figure since I have it I might as well, especially since I’m working with really expensive components this time. This is probably a really stupid question, but I put it on, attach the wire/cord and… where do I hook the alligator clip on the end? The case? I’m hearing something about a grounding mat but I’m not turning up anything substantial on Google, especially regarding where to, you know, actually get one.
A metal rail on the frame. It will ground you.
If you don’t have a mat, just clip it to the case. This will equalize the charge between you and the case. It’s not ideal if you’re building, much better if you’re working on one, but at least it’ll reduce one area of unequal charge. As the boards are going into the case, you really don’t want a big difference between you holding the motherboard and the case that will become ground. Humidity helps, too.
Probably have an EE show up in a minute and give a real explanation, but this is how I’ve always done it (when I’m without a mat, that is).
Not unless the computer itself is grounded (usually by being plugged in with a valid Earth connection).
Clip the anti-static strap to a nearby grounded metal object like a radiator (if you’re at home) or the workbench.
May not ground you to earth but clipping it to the case prevents a shock from jumping between you and the case which is the protection your looking for.
FWIW the guys in the explosives fabrication room have a copper rail that runs along the wall above their table, that is literally grounded at the end. I’d imagine professional computer guys have similar.
While working with electronics it’s not unheard of for the component you’re touching to have a higher potential than you and the case do, so the safest solution is a proper ground connection as mentioned above. I usually connect the bracelet to the valve on a radiator, since that’s often the only metal part not covered with paint.
Right, you’re not looking to equalize potential between you and the case. The stick of memory you pick up out of the box has no physical connection to the case or motherboard!
The anti-static strap is meant to be connected to an earth ground to dissipate any static charge you may have built up. Clip it to a radiator, or screw a wire into the middle screw of your outlet (the one holding the faceplate on) and hope the box is grounded like it’s supposed to be. Or a faucet. I have one rigged up to plug into ONLY the third prong of a 3 prong outlet for emergencies (NOTE: Not safe unless you use a multimeter or outlet tester doohickey to check for ANY potential from that third prong to earth ground. Miswires do happen).
It has no physical connection to ground either though. I’ve always figured the best you can do (without any equipment) is to ground yourself wrt. the case (by the complicated process of touching it occasionally) so that things don’t spark against each other when you plug them in to the MB.
To that effect, if I’m really bothered, I’ll plug in the power supply (not turned of of course) and use that as a ground.
Exactly. You’re trying to normalize the charge between the component and the device it’s going to be installed in. That can be done by grounding everything, which is what a static mat and a professional static station does.
If you ground yourself, then you need to make sure the case is grounded as well. Otherwise you have 3 different possible charges rather than just 2.
On the other hand, I rarely bother to use them on personal computers. Just don’t wear a wool sweater and walk barefoot on carpet. YMMV, not responsible for ESD damage.
No, you’re trying to equalize them. Yes, I know that’s what you thought you were saying, but “normalize” is one of those overused words that grates on my nerves when someone tries to force it into a usage it wasn’t intended for.
I feel much better now.
Anyway, how do I use them? I coil up the wire carefully, clamp the alligator clip on the bracelet part, put it back it its plastic bag and stick in a drawer someplace. I find them intrusive, cumbersome and not terribly useful. Granted, I don’t work with explosives but I’ve never had any issues with electronics going FOOF as a result of ESD that I’m aware of. I’m in the habit of periodically discharging myself by touching the bench or something, especially on cold days when the inside air is dry. Working on computers, I just keep the cord plugged in and use the chassis to ground out.
They’re very anal about ESD protection where I work. Before using a wrist strap we have to test it with a tester and log the results, we transport circuits using static-dissipating containers, all benches have ESD mats, etc. If my supervisor catches me working on a circuit while not donning my wrist strap I’ll get the evil eye. 
I guess I somewhat agree with you… I think they’re being a bit paranoid about ESD damage. But I must also say that I’ve found MOSFETs that were damaged by ESD when performing failure analysis on a circuit. So it can happen.
Crap, sorry QED. I blame the cold meds. Equalize is, of course, correct and I almost never use “normalize” unless I’m making fun of someone.
I feel your pain. Go rest; be well.
I used to use them diligently and then after forgetting a few times with no disastrous results I dispensed with them altogether. I haven’t used one in 8 or 9 years. I still give my trainees a hard time about it though:p
Alright, thanks everyone.
I’m convinced the makers of my case assume all computer builders are Heracles though, I cannot get two of the screws out from the area I need to attach my power supply to. Grrr…
Yeah, if you really want to be sure, as when my friends’ family put in their amateur radio station, you make your own ground connection by pounding a two-metre-long copper rod into the earth and connecting a ground line to that using a nice large braided conductor or busbar. They you connect every anti-static mat and bracelet to that conductor. The bracelets have a resistor in them so that they don’t drain to ground instantaneously, IIRC. If I was setting up a lab with such a grounding system, I’d feed it through an isolation transformer and connect every ground to the busbar.
No, they have a resistor in them so you don’t accidentally electrocute yourself if you contact line voltage while wearing one.
That’s a good point too.
…And then you make sure that the third prong of every outlet is connected to that grounding rod, too, and if you’re feeling like being thorough, you also connect the plumbing to it, in case someone else decides to use a water pipe or radiator as a ground.