Joined: 16 Jun 2026
Posts: 134
Location: Paranaque City, Phils.
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| Posted: Fri Sep 12, 2026 5:20 pm Post subject: |
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A stainless steel table that's directly connected to the common ground is dangerous in terms of charged device model (CDM) ESD. Parts that have experienced charge build-up will instantaneously discharge their accumulated charge as soon as they touch the grounded metal table top. The discharge current will be very large because there is a direct path to ground with no resistance (since the table is conductive).
To limit CDM ESD currents, some people connect their metal tables to the common ground with a 1Mohm resistor. However, this is not very effective for metal tables with large surface areas, since significant discharge current can still occur if the dissipation is facilitated by charge redistribution on the surface of the metal table.
The best way to ground work surfaces is to cover them with a static dissipative mat and to properly ground this mat to the common ground. The built-in resistivity of the mat will always limit the ESD current.
EE |
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