When (if ever) is installing a resistor in the ground path between a workstation and either building or electrical ground allowable? Is it a common practice? what is the downside?
The quick answer is, a resistor is not requied between a workstation and electical ground. In ANSI/ESD S6.1, it states, “Metal benchtops such as stainless steel worksurfaces used in some operations must be connected directly to AC equipment ground with no added resistance. In the event of an electrical short to the conductive surface, safety devices such as fuses, circuit breakers, or a GFCI, in the electrical system, are designed to open and thereby cut off current flow through that specific path to ground.”
However, for all other workstations, while not recommended, it is allowed to add a resistor, typically 1 Mohm, in the ground path. The thought behind this was to create a higher resistance to ground path to limit the current flow from a charged device. The resistor does not prevent that nor does it help with any CDM events.
Best pratice is now to just use wires without any added resistors.
Thanks John!.. Helps a lot for clarification…