3M - Methods of Personnel Grounding - What to Use and Why It ’s Needed

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Background


Personnel grounding is a corner stone of safeguarding static sensitive electronic devices in production areas. People are one of the greatest sources of static electricity. As we move about, we continually touch and move away from things around us. This contact and separation with objects leaves charge on us and the objects. Static charge generated by contact and separation is called Tribocharging. A good example of tribocharging involves walking across carpet. (See figure 1) As we walk, our shoes contact and separate from the flooring or carpet. Charge effectively accumulates on our bodies. When you touch a grounded object or an object with a different charge level, like a door knob, electrostatic discharge (ESD) occurs.


By grounding people, their static charges are recombined with opposite charges from the earth as the charges on people are generated. This avoids ESD and protects sensitive electronic devices.


Grounding Methods
Wrist Straps


A wrist strap consists of a conductive cuff (also call a band) and a wire that connects a person to ground (See photo 1). This wire is usually coiled and called a coil cord. The wire expands as the person moves away from the ground connection, and retracts as the person approaches the ground connection. Expanding and retracting keeps the wire from interfering with the wearer’s work...



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