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I have ESD charge vulnerable PCBs and I am going to use them to make some tests outdoor. I am thinking of a way to protect them while doing the test since they are going to be touched by hand and maybe laid on floor or conducting surfaces. Because that the test is outdoor there is no way for me to use ESD wrist strap and be connected to ground.

For the time being I am not able to afford buying plastic boxes for protection. I have got an idea to make a box from cardboard and put a flipped aluminum foil inside of it (like the anti-static bags). I do not know how much effective the cardboard box is but it should work to some extent.

What are the disadvantages of this way? Are there any other ideas to protect the PCBs?

EDIT:

The PCBs are for wireless communication and each one has a 6.5 cm whip antenna. Each PCB is powered by a 12V battery.

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    \$\begingroup\$ If your boards are that sensitive to ESD, you should have ESD protection components ON the board. Transient voltage suppressors (TVS devices) are a MUST. \$\endgroup\$
    – DerStrom8
    May 16, 2017 at 19:25
  • \$\begingroup\$ What do you mean "ESD vulnerable PCBs"? Do these "PCBs" have exposed metal areas (wires) for sensors, or all sensors are soldered on these PCB? What do they sense, electric field, or something else? \$\endgroup\$
    – Ale..chenski
    May 16, 2017 at 19:39
  • \$\begingroup\$ @Ali I mean that the PCBs are not desgined to handle ESD charges. There is no ESD protection at all. \$\endgroup\$
    – Macit
    May 16, 2017 at 19:55
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    \$\begingroup\$ And I am asking what kind of sensors or antennas are there. Why do you need a box? Why don't just wrap your boards with electric tape, and then wrap everything in a kitchen-grade aluminum foil? \$\endgroup\$
    – Ale..chenski
    May 16, 2017 at 20:01
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    \$\begingroup\$ Dont see what indoor vs outdoor has to do with ESD, inside, outside, upstairs, downstairs, etc follow the same practices. \$\endgroup\$
    – old_timer
    May 16, 2017 at 20:46

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What are the disadvantages of this way? Are there any other ideas to protect the PCBs?

If the components really are ESD critical, Cardboard and most plastics are not ESD safe. Most materials are not ESD safe, because they generate static fields through triboelectric charging. That means your PCB moving around on the inside of the box could generate a field and still kill components. However if you make the inside of the box you could make it ESD safe.

The way that this is overcome is to place ESD sensitive materials in a Faraday cage. If you have conductive material for a box, the electric fields will be zero on the inside of the box (assuming no internal charges exist, which shouldn't apply to PCB's). Anti static bags work in this manner by making a faraday cage with conductive coated plastic.

So you could use an anti static bag, or anything conductive, even aluminum foil would work, a metal box would work.

The other problem is when you get the electronics out of the box, since then you would be introducing them to stray static fields. If you can't find a suitable ground (which would be unusual, because you must be powering these electronics somehow), you could use a metal table and ground a wrist strap to that, the most important thing is keeping all potentials zero.

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  • \$\begingroup\$ Actually I want to power the PCBs while they are inside the box. And there is antenna (sorry I did not mention that before) so I was thinking about letting the top side of the box open. \$\endgroup\$
    – Macit
    May 16, 2017 at 23:11

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