How to ground a ESD mat?

in Genius Bar edited January 2014
Oops... How to ground *an* ESD mat?

I apologize in advance for asking what should be easily answered. You'd think that a simple google search would yield a lot of useful results, but I have been unsuccessful. So now I turn to one of my favorite tech sites in hope that you wonderful people can help a guy out.

How do I ground an ESD mat to make it safe for working on Macs? For the most part I'll be traveling to people's homes installing RAM and replacing internal hard drives. I'd need a mobile grounding solution and am hoping I won't have to run a copper wire out a window and drive a foot long copper stake into the ground...

I purchased a 3M Static Dissipative Table Mat (8214) from my local hardware store. It included a Wrist Strap/Table Mat Grounding System (3048) as well. Unfortunately a wrist strap was not available. I'm thinking of ordering a 3M Adjustable Wrist Strap with 5' Cord (2214).

Coming from the grounding system (3048) there is 15' cord ending with a small circle. What am I supposed to do with this? Can I connected it to a table some how? Stick it into the ground of a wall socket? I'd really like to avoid damaging a client's computer. I've included a picture:



  • Reply 1 of 3
    I talked to my uncle who is an electrician, but not a computer repair man. He urged me not to connect to the "ground" of an outlet. His reasons were three fold. (1) The home may be older and no ground may be available. (2) The ground may not have been installed properly during a remodel or for other reasons is no longer functioning as a ground. (3) All grounds in the home are connected and if there is a slight discharge moving through them and I happen to make a better ground than the home's ground then I could potentially damage the computer and shock myself.

    He recommended that I create my own ground. Drive a stake into the ground and connected it with a conductive copper wire to the ESD Mat (and myself as a result). Not much of an issue if I'm working in one area, but annoying if traveling to different client homes. Annoying, but potentially necessary.

    I'd prefer to hear from first hand experience though.
  • Reply 2 of 3
    I've done a lot of research in the last couple days and gotten several responses from different sources. There seem to be 3 major schools of thought when it comes to ESD safety.

    (1) Minimal protection is required, if any at all. Plenty of people claim to simply touch objects around them and avoid moonwalking across carpet. That is sufficient to avoid damaging computer equipment.

    (2) Connecting to the ground of a receptacle is normal procedure and perfectly safe. "The ground" of a receptacle is there for a reason, right?

    (3) The only safe and reliable way to ground an ESD mat, and one's self, is to pound a stake into the ground. If this isn't possible at least connect to an unpainted metal pipe or structural material that leads to the ground. Connecting to any system where there are unknowns carries a small risk, but a risk nonetheless. Even testing the ground of a receptacle may not be accurate enough as there are too many variables.

    So, it seems that for the simple RAM install on a shoe string budget, the first is just fine. Typical servicing and PC building is probably well suited for the second, especially when working in the same trusted environment. Lastly, when absolute certainty is desired, connecting to unpainted metal pipes or, better yet, creating one's own ground with a stake driven into mother earth gives the greatest assurance. Anyone doing house calls or working on other people's expensive computers might be best served by considering the last option despite the extra annoyances that go into it.
  • Reply 3 of 3
    dayrobotdayrobot Posts: 133member

    I'm afraid you won't be coming back, but my own experience is kind of in the middle of the road...

    Having serviced computers for many years, i've never had an ESD issue, unless it was other people coming over and grabbing parts, even after i've told them not to.

    I simply ground myself by touching the back of a plugged-in desktop computer, after every time i've walked across the room or made a significant movement.

    I consider this to be pretty reliable, because:

    1) A desktop computer has enough metal parts to absorb ESD, even if the home's ground is unreliable

    2) I only touch it when i have reasonable doubt that i may be carrying electrostatic, so i'm safe from the sudden spikes (from other grounding appliances) that could cross over in case of a wrist strap

    I agree with your analysis though...

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