ESD Systems - Questions And Answers

Order# S0207492 We are trying to comply to ESD Assoc. ESD ADV53.1-1995, sec 4.2.2 Electrical Requirement for part A. Worksuface - Resistance between 1 x 10+6 ohms and 1 x 10+9 ohms. The drag chains, P/N 14000 measure 920-940Kohm of the six samples measured. 50 drag chains were purchased. At this level, we cannot comply to the spec, more resistance required.

It would be acceptable if a Drag Chain is less than 1 ohm. Our drag chain contains a 1 megohm ohm resistor and the measurement you obtain of 920-940 Kohm is within tolerance.
The resistance to ground (RTG) measurement is to be resistance in series and the surface that you store ESD sensitive items on should be between 1 x 10+6 ohms and 1 x 10+9 ohms.

Note word “worksurface” from ESD-ADV53.1-1995 ESD Protective Workstations

“Electrical Requirements

· Workstation elements shall be connected to, and maintain electrical continuity to, the common point ground as follows:

· Worksurfaces - Resistance: Between 1 x 10^6 ohms and 1 x 10^9 ohms (as measured per para. 6.3 of this document).”

The RTG test should be with the Drag Chain installed and placing one 5 pound electrode on the surfaces and the sensing test lead to equipment ground using a Surface Resistance Test Kit.

Alternatively, some users test with two 5 pound electrodes, measuring resistance top to top (RTT) placing one electrode on the surfaces and the other electrode on the ESD floor which the Drag Chain is in contact with.

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