To start off: I was explaining to my friend that I don’t have a grounding point in my house (plumbing is PVC, outlets are gcfi protected only, not allowed to drive a grounding rod into the ground, etc…) and that I’ve just been handling sensitive electronics with just luck and preparation (humidity, moisturizer, no synthetic clothing, etc…) all this time. He told me to just wire myself to a good, multimeter tested, grounding point in a car and that will discharge any built-up static electricity. I’m not smart enough to argue with him on this subject but that doesnt seem the safest. Would that work or should I just keep doing my method? My understanding is that chassis grounding is essentially replacing wires with the frame so the outcome would just be connecting myself to the negative terminal of a car battery.

Tldr: I’m explaining my lack of a grounding point at home for sensitive electronics and is advised by my friend to wire myself to a grounded point in a car to discharge built-up static electricity. However, I’m uncertain about the safety of this suggestion and questions whether my current method of handling electronics with precautions is sufficient.

Edit: lmao people are really getting hung up on the no grounded outlet part. Umm my best explanation I guess is that its an older house that had 2 prong outlets and was “updated” with gfci protected outlets afterwards think the breakers as well. My understanding is that its up to code but I’m not an electrician. As for the plumbing I’m sure there’s still copper somewhere but the majority has been updated to pvc over the years. Again it’s not my house I don’t want to go biting the hand that feeds me. Thank you though, haha

Edit #2: thank you all so much for the helpful advice, I really appreciate all of you!

  • @litchraleeEnglish
    18•5 months ago

    A static dissipating mat is designed to be somewhat conductive, so that any static charges that build up on a PCB or on yourself are distributed and equalized across the mat and anything in contact with it. The point is that you cannot have a sudden static discharge between two objects which have equalized charges (eg between your finger and a sensitive chip).

    With that in mind, it should make sense that, when possible, you want to extend the “reach” of your mat by equalizing it with other things that can hold a charge, such as the floor, the door handle, the light switch, etc. All of those home furnishings are indirectly in contact with terra firma, and do slowly drain any accumulated charge to earth. But your electrical ground system provides a convenient, low-resistance copper path to quickly drain charge. So if it’s available, you’d want to electrically “anchor” your mat to the Earth’s charge using the electrical ground. Otherwise, just keep everything on or attached to the mat, including yourself by way of the wrist strap.

    As an aside, in the electronics lab at my company, the floor was redone to the tune of six figures to install a semi conductive floor, so that engineers could wear ankle straps instead of wrist straps, all to protect from ESD damage. The reason that floor and your matt are only semi conducting is that an all-copper floor or mat could end up shorting out a PCB. So their resistance is a precise value which lets charges equalize but not too low to cause shorting issues.

    • ExtrasOP
      3•5 months ago

      Damn that is interesting as hell I honestly had no clue I really appreciate it. Think I’ll order one with my next paycheck and a wrist strap

      Edit: Just so I can understand 100% since the conductivity of the mat is doing most of the work why wouldn’t a sheet of conductive metal work here? Assuming both the person and electronic is in contact.

      • @litchraleeEnglish
        3•5 months ago

        A highly-conductive metal sheet would only work fine if you were a latex balloon engineer and there were no electric sources – batteries or mains – involved in your work. In that scenario, the sheet would be very effective at draining static charge from the balloon.

        But for electrical engineering, a large sheet of metal might as well be a puddle of salt water: the risk of electric shorts is too high, whether that be shorting out the pins on the bottom side of a PCB, or providing a path for a loose mains AC wire to go directly to ground, or indirectly through a human…

        So there has to be a balance between the need to drain static charge, and the need to keep devices from shorting out and also protecting people. Controlling the resistance lets us achieve that balance. That said, mats aren’t perfect, since a mat isn’t terribly heat-resistant and could melt when doing hot-air reflow work. As I mentioned, my company invested a great deal into their lab, because they were seeing one-off failures of five figure prototypes. So it made sense to spend a lot to improve the lab.

        But for domestic work, depending on how your devices are valued, it might be sufficient to use a sturdy wood desk top, a wrist strap to its metal frame, a humidifier if your space is very dry (eg < 30% RH), and maybe don’t wear wool or socks while doing electronics work. In the end, ESD damage is a statistics game and we try to improve the odds where it makes sense.