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Manufacturing and handling the unpowered boards, the assembly workers often use strict ESD control: dissipative mats, smocks, and grounded wrist bands.

As an embedded engineer, I am always powering and probing up my raw boards (without the plastics enclosures) at my cubicle... JTAG debugging them without any sort of ESD safety.

What is the recommended guidance on this? Should I be worried about ESD? Do I need to be wearing any ESD gloves/strap?

note: the humidity in my office is around 40-50%

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My entire office is carpeted, and we constantly debug/test raw PCBAs at our desks. I take care to ground myself on metal objects around me, and I have an ESD mat on my desk. When I have to transport boards, I put them in ESD bags. I also take care to ground myself after getting up from my chair, or upon sitting down. When passing off boards to others, we always do the "EE's handshake", where we touch hands before exchanging the PCBAs.

This has worked well for us, and I have yet to see a PCBA damaged due to unintentional ESD.

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    \$\begingroup\$ This is how I do it, too. In addition, I try to be in contact with the ESD mat whenever I'm handling or probing the boards. Nothing difficult: If I'm picking something up with one hand I rest my other hand on the mat first. When I'm soldering/probing/etc, I would be resting my elbows or forearms on the table/mat anyway :) \$\endgroup\$ – bitsmack Aug 23 '18 at 17:34
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    \$\begingroup\$ That being said, the "correct" way is to wear a strap, etc... \$\endgroup\$ – bitsmack Aug 23 '18 at 17:37
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    \$\begingroup\$ Agreed. I also would take into consideration how expensive the hardware being worked on is. If I'm testing a motherboard, I'm a lot more careful than with a $3.00 prototype PCBA... \$\endgroup\$ – Daniel Aug 23 '18 at 17:55
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Technically, yes. However, in my experience most boards seem to be much less ESD sensitive after they are assembled. Some logic families can still be very sensitive; we used to work with FCT (Fast CMOS Technology) logic from IDT and that definitely needed wrist straps all the time.

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  • \$\begingroup\$ good point about assembled PWAs, they are indeed less sensative \$\endgroup\$ – hassan789 Aug 23 '18 at 19:05
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It is generally a good idea to wear a wrist strap, keep in mind there should be 1MΩ of resistance between the strap and whatever ground your connecting it to, which reduces the chance of you becoming part of a circuit in the event of a short and possible injury.

I have seen ESD discharges ruin flash on micros before and the board needed to be reflashed. Most ports are protected these days with ESD diodes\diodes, but intermittency caused by ESD can cost you hours of debugging to find the problem is the hardware and not the software. Any form of ESD mitigation is recommended, in other words, wear the wrist strap.

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