67

Last winter in Japan, some of my friends were buying bracelets like this, that claim to prevent or reduce static shocks:

Antistatic bracelet

Here is an advertisement picture describing how it is supposed to be used, please note that unlike ground bracelets, it is not connected to anything but your wrist:

key opening car with antistatic bracelet on

Here is the science behind it:

antistatic fiber bracelet scientific explanation

My translation:

This is a static electricity prevention bracelet, it reduces the disagreeable "pachipachi" during dry winters.

It works by dispersing the body's charges into the air.

Wear it directly on the skin. You can hope for most efficient when not covered completely with clothes.

In the figure, the text in red reads "conductive fabric" and the text at the right reads "extra electrons fly away".

Question: Is this claim (reduce static shocks with just a small non-grounded bracelet) possibly true?

nic
  • 1,466
  • 2
  • 14
  • 23

1 Answers1

93

No, it is not true

On the Wikipedia page on "Antistatic Device" there were several references to these kinds of things having been examined in a serious manner.

ESD Journal

It is our opinion that no currently available methods or devices exist which will effectively ground a person without a tethered cord to ground or at least a large capacitance.

Sorry! Something that sounds too good to be true probably is.

ESD Systems FAQ

No. This is not a viable ESD control device to employ in ESD safe areas. These passive "wireless" wrist straps have severe limitations. Assuming you were tribocharged to 10 KV and wearing the "wireless" wrist strap, it would take many hours (days even depending on the ambient RH) to get you below 5 KV, never the less 10 Volts. Most (if not all) of the charge reduction would be due to natural recombination of the charges on your skin (and now metal casing of your "wireless" wrist strap) with the air molecules and the natural conductance of the air through water vapor content (RH).

P.S. You could get the same effect by cutting your hair to about 1/4" long and then putting conductive jell in your hair. The ends of your now conductive hair would act like corona discharge points at extremely high voltages to bleed current into the air or help to enhance the natural recombination process. The fact that your hair would need to come in very close proximity [0.1 to 1.5 inches] to ground or any other potential with at least a 3 Kilovolt difference (due to the dielectric strength of air) or enhancing the natural conductivity of the air needs to be considered to even get you down below a few KV.

EDIT: Thank you to 0xDBFB7 for sharing this video (spicy language, like "bullshit"); it is yet another review of a supposed wireless wrist strap charge dissipator.

Community
  • 1
  • For reference, you can feel static discharge at voltages as low as 3 kV, so according to the second quote these bracelets aren't even effective at reducing static shock. (Which is a significantly lower bar than "safe for protection when working with ESD-sensitive devices".) – Ajedi32 Aug 10 '18 at 13:53
  • 1
    See also this video from the excellent Dave Jones: https://www.youtube.com/watch?v=nvgW5iWXbts – 0xDBFB7 Aug 10 '18 at 14:49
  • 27
    Just as a note, the packaging does not indicate nor suggest that this is acceptable for ESD protection. It seems to be marketed solely as an electrostatic shock reduction device for everyday life. – CramerTV Aug 10 '18 at 15:53
  • 5
    @MichaelK, I wasn't suggesting that it works nor that your answer is wrong. I was simply pointing out that there are very different thresholds between the amount of static required for damage to electronic devices and what one feels in a normal static shock. – CramerTV Aug 10 '18 at 16:19
  • Dissipating static charges into the air is certainly possible ([airplanes do it all the time](https://aviation.stackexchange.com/q/2720/1677)), it's just this product that doesn't work for the purpose. – Mark Aug 10 '18 at 20:09
  • 9
    This isn't one of them, but there are [antistatic devices](https://c.76.my/Malaysia/japanese-technology-lcd-anti-static-discharger-key-chain-oloyy-1305-09-oloyy@1.jpg) that are essentially just a conductive service that you hold so the shock is not painful (or even imperceptible). You can often do the same thing with a coin. They aren't grounding devices, and are entirely unsuitable for ESD protection, but are intended so it doesn't hurt to touch, say, doorknobs. – Zach Lipton Aug 10 '18 at 22:54