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We've been having a lot of problems in my office with ESD. People touch cubicle frames and monitors shut off momentarily, painful shocks through laptops, etc. I'm worried about equipment getting damaged and I'm fed up with getting shocked by furniture.

As the EE in the office, I went and bought a bunch of wrist straps, table mats, and staticide carpet spray. While shopping, I discovered this Desco 09839 USB Ground Adapter, which is a USB port on one end with a banana jack on the other end of the cable. Checking it with a multimeter, the signal ground pin is connected directly to the banana plug. The shield is not.

USB Ground Adapter

This smells like a good way to damage a laptop, particularly if it's shorted to the wrist strap. Under what circumstances would I want to use this as part of an ESD protection strategy? My first thought is to connect it to earth through a separate 1M resistor from my wrist strap to help prevent discharges to the laptop chassis.

The AC-DC adapters for our laptops are Class II with functional earthing. They have a third prong on the AC but I assume it only goes to a line filter.

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  • \$\begingroup\$ What kind of flooring do you have in your office? \$\endgroup\$ – Ale..chenski Apr 2 '19 at 1:55
  • \$\begingroup\$ @Ale..chenski It's all carpet. \$\endgroup\$ – Joe Baker Apr 2 '19 at 2:41
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    \$\begingroup\$ Is this ESD?? or is that area of the building working with ungrounded RETURN or NEUTRAL wires? \$\endgroup\$ – analogsystemsrf Apr 2 '19 at 2:58
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    \$\begingroup\$ I would definitely change the carpet first. A time ago we had a cheap laminate floor and same issues, computers, devices, ... burned. Check for anti-static flooring, could be vinyl tiles, laminate,...many ways but eliminate the carpet as it is known to give shocks . \$\endgroup\$ – Marko Buršič Apr 2 '19 at 10:30
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Basics of an Electrostatic Protected Area (EPA):

  1. Ground all conductors (including people)
  2. Remove all insulators

I appreciate that in an office environment, you may be somewhat limited, so here are some other things to consider:

  • Polystyrene cups could be replaced with cardboard
  • Document wallets could be replaced with ESD document wallets
  • Grounded document organisers can be placed on desks. Paper can be a source of static electricity
  • If you have access, increase the humidity of the HVAC system.
  • Air Ionizers can be fitted to neutralise charge on insulators
  • ESD flooring and ESD chairs could be installed, if the budget exists
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If that device has a resistor built in then its fit for use as it will help to ground users to the potential of the laptop / computer without damages. Typically the resistance I believe is 1MΩ.

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