Grounding Methods (Electrical Bonding) of Wrist Straps
Static electrons can sit on the surface of our skin. This can cause us to hold a positive or negative charge. The charge can then accumulate on us with greater mass if we are electrically isolated from the ground underneath our feet. This can happen when we are wearing insulating shoes- like tennis shoes or other rubber-based footwear.
Materials like wood and wool are also insulating. Walking up and down a wool carpet with tennis shoes can easily cause us to hold static on our skin and clothes.
When we go to handle electronics we want to make sure we are not electrically isolated, but instead electrically bonded. This allows those static electrons to discharge from our clothes and skin to the ground beneath our feet. Wearing a wrist strap connected to an electrical outlet is the most common way to “ground” ourselves.
1. How do I connect the Wrist Strap to a Grounding Cord?
Your wrist strap should come with a 4mm stud snap that protrudes from the outside surface of the strap. The inside is usually silver-suffused nylon or metal-banded to capture static directly from your skin’s surface at a conductive rate.
The 4mm stud snap on the wrist strap then is connected to a coiled grounding cord.
The coil cord prevents the cord from dragging or being stepped on.
2. How do I connect the Coil Cord to Ground?
Electrical outlets are normally the best ground for a wrist strap in any building. This is because the wiring of outlets typically follows the piping of the building to earth underneath the building.
The coil cord ends in a plug that can be plugged into a banana jack on a variety of grounds: a bench mount ground (which grounds the wrist strap separate from anything else), or a common point ground (which grounds both an ESD mat and a wrist strap).
Whether you use a bench mount ground or common point ground it will have a ground cable attached to it that ends in an “eyelet”. This eyelet is a metal ring that you can screw into the nearest electrical outlet to transfer static from the ground to the electrical outlet.
If you cannot reach an electrical outlet the next best thing to do is to use the “alligator clip” that comes with the wrist strap. Slide the clip over the cord’s plug so that it can be clipped to a railing that leads to your floor below.
3. ESD Testing Wrist Straps
To confirm your wrist strap is providing the correct amount of ESD resistance we recommend regular testing.
The combo tester is setup to meet the requirements of ESD TR53.
The testing looks for pass or fail reading from the wrist strap. This means if the wrist strap measures less than 3.5 x 107 (35,000,000) ohms / square it will pass.