The Awkward Engineer and The Grounding Procedure

Hi all!

Today's post is a bit on the nerdy side, but with the dry winter air in New England, I'm reminded of some old on-the-job training I received on electrostatic discharge. (ESD)

ESD is the fancy word for the zap of static electricity you may get when you walk across a carpet and touch a metal doorknob.

Most of the on-the-job training was about how to prevent it. It's very easy to build up a charge of several hundred volts, just walking around a carpeted room, and an actual zap of static electricity is in the low thousands of volts, enough to ionize the air. The current, and hence the total power, is relatively low, but it can easily damage some electronic components.

The typical strategy for prevention is to use special clothing, desk and flooring materials, shoe covers, and grounding straps to dissipate electrical charges. Rather than building up and rapidly discharging, the charge slowly bleeds through the material until the electric potential has equalized.

One team in the lab was working with some unusually sensitive components and the typical strategies weren't enough. They developed a procedure where two assembly technicians would need to connect wrist straps and shake hands in a particular sequence to equalize electrical potentials prior to passing physical parts or tools between them. They called it the "grounding dance".

Fast forward many years later, and one day, after kissing my wife and giving her a resounding electrical shock on the lips, I told her about the grounding procedure.

So if you ever see us get in the car together, lean in for a kiss, then abruptly pause, you'll know what we're doing. The next step is to paw at the air until our hands meet and then proceed once the electrical potential has equalized. It's the grounding dance.

best regards,
Sam Feller
aka THE Awkward Engineer

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