Electrostatic discharge (ESD) is a rapid transfer of static charge between two different objects. People most commonly experience ESD when they touch metal after walking on carpet and receive a small shock. This shock typically doesn’t cause any harm. In some cases, however, even a small amount of ESD can damage an object. ESD is an issue in some industrial environments; the discharge that occurs can create extensive damage to sensitive instruments and electrical equipment. This is because the swift transfer of charge generates intense heat, which can melt or vaporize electrical components.
ESD may cause two types of damage to electrical equipment. These types are:
- Catastrophic Failure. In this case, permanent damage occurs and the device is likely to no longer function. ESD events can lead to total device failures, junction breakdowns, and the melting of metal. Typically, catastrophic failures are detected during testing before the device is shipped.
- Latent Defect. Devices that suffer latent defects often are partially degraded and have a reduced operating life. These defects are malfunctions that are challenging to identify. Unlike catastrophic failures, latent defects are very difficult to detect or prove with basic performance tests. The damaged device will likely be included in the assembly of a finished product, and will seemingly work correctly only to fail sometime in the future. Often the defect does not become apparent until after a user has put the device into service.
It doesn’t take much to create damage to electrical devices. For example, in order to feel a static shock when you touch metal, you must have several thousand volts of electromotive force on your body. For damage to occur to electrical components, however, all it takes is 100 volts. This low level is continuously present on our bodies.
To prevent causing damage due to an accidental discharge, it’s important to take precautions and use grounding accessories to reduce electrical currents and protect electrical components. The EOS/ESD Association establishes standards for the theory and practice of ESD avoidance. A common practice is for workers to ground themselves or the devices they handle using static shielding bags, anti-static mats, and ground bracelets/anti-static wrist straps. These will safely direct electricity to the ground and absorb static so that operations may be conducted harmlessly.
ESD signs also provide vital communication and remind workers to be cautious around electrically sensitive components, or warn of ESD control areas. These signs incorporate universal pictograms that indicate ESD hazards:
ESD signage and awareness aids facilities in preventing electrostatic damage to devices, which improves the manufacturing process and eliminates waste.