Getting Rid of Charges Part 3: Workstation Grounding

by Andy on February 13, 2012

ESD-Safe Bench Mat While personal grounding equipment is important, people are not the only hazard to electronic devices. Any ESD-sensitive device can also be damaged from charges built up while moving it across a work area or from other charged items in the area. To reduce and counteract the build-up of static charges, ESD-safe matting and ionizers are used in areas where electro-static discharge is a concern.

ESD-Safe Matting

ESD-safe mats are integral parts of static safe work areas. These mats discharge any introduced charges through a connected wire and ultimately transfer them to either an electrical or earth grounding point. Connecting to an electrical ground, which is either the screw through the metal plate covering an outlet or a screw on the outlet casing inside the wall is fairly simple while finding and attaching the wire to an earth ground (which is generally a metal rod hammered into the ground before the foundation is poured) is substantially harder. It is important to use a ground tester to make sure that the outlet you are using for your electrical ground is connected properly and safely to an earth ground. A faulty ground could result in damage to ESD-sensitive devices or personal harm if the ground is connected to a live wire.

Matting for ESD-safe work areas are normally dissipative or will have a dissipative top layer. Compared to a conductive surface, a dissipative top layer slows down how fast a static charge drains while still providing a path to ground for any built up charges. By draining the charge more slowly; the dissipative surface provides less risk to the static sensitive devices.

Ionizers

Bench top ionizers and overhead ionizers are used to neutralize insulators and any other devices that are not fully grounded or can’t be grounded. Most ionizers work by using a fan to spread positive and negative ions across an area. These ions are naturally attracted to their opposite charges, so positive ions neutralized negative areas and negative ions neutralize positive areas. Any left over ions will neutralize themselves as they find their opposite charges. This allows for an area of neutral charge by slowly and safely neutralizing charged objects in a work area.

Next week will be our last in this series on grounding, where we will explain how grounding works at the level of the earth. Come back next week for more information and be sure to read our previous articles on grounding below!

Getting Rid of Charges Part 1

Getting Rid of Charges Part 2

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