TB-2000 March 2012 Page 1 of 4

Installation and

Maintenance of ESD Mats

Introduction

The purpose of an ESD worksurface is to aid in the prevention

of damage to ESD sensitive components and assemblies from

electrostatic discharge. An ESD worksurface provides protection in

the following two ways:

1. Providing an antistatic worksurface area that will limit static

electricity generation.

2. Removing the charge from a conductive object placed on the

worksurface.

A dissipative worksurface having a surface resistance of at

least 1 x 10E6, but less than 1 x 10E9 ohms is recommended

by worksurface standard ANSI/ESD S4.1. Dissipative materials

minimize the generation of static charges, and will dissipate a

charge slow enough so that a spark will not occur. Dissipative

materials are usually the preferred choice for bench top

worksurfaces.

Conductive materials are the quickest to remove a charge,

but they can also cause damage by discharging too rapidly.

Conductive materials are usually used as floor mats, which is

defined by ANSI/ESD S7.1 as less than 1 x 10E6 ohms.

General Grounding Guidelines

1. ANSI/ESD S20.20 requires that all conductors in an ESD

protected area, including personnel, must be grounded.

2. The ESD ground must be tied directly to and at the same

potential as the building or “green wire” equipment ground.

3. Per ANSI/ESD S20.20, the ESD control program can in no

way replace or supercede any requirements for personnel

safety. Ground fault circuit interrupters (GFCI) and other safety

protection should be considered wherever personnel might

come into contact with electrical sources.

4. All electrical outlets should be verified for proper wiring

configuration, resistance or impedance and GFCI function when

the mat is installed and periodically thereafter.

Common Point Grounds

A common point ground is defined by the grounding standard

ANSI/ESD S6.1, as:

1. A grounded device where two or more conductors are bonded.

2. A system or method for connecting two or more grounding

conductors to the same electrical potential.

Examples of common point grounds with ground cords are

illustrated below.

Figure 2. Other ground cords.

Figure 3. 09814 with screw allows ground cord to be bolted to mat

to keep cord from disconnecting.

Common point grounds are designed to provide ground for

worksurface mats, wrist straps, and other items.

NOTE: DO NOT DAISY CHAIN. Because of the high resistances

inherent to many types of protective surfaces, daisy chaining of

these materials can severely limit their ability to properly dissipate

and protect against static charges.

09817

09814

DESCO WEST

- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178

DESCO EAST - One Colgate Way

, Canton, MA 02021-1407 • (781) 821-8370 • Web Site: Desco.com

TECHNICAL BULLETIN TB-2000

Made in the

United States of America

© 2012 DESCO INDUSTRIES INC.

Employee Owned

09835

09740

Figure 1. Typical common point grounds.

09837

09825

COMMON POINT GROUND

Per ANSI/ESD S6.1, Grounding section 4.1.1 “Every element to be

grounded at an ESD protected station shall be connected to the

same common point ground.”

ESD Handbook ESD TR20.20 section 5.1.3 Basic Grounding

Requirements “The first step in ensuring that everything in an

EPA is at the same electrical potential is to ground all conductive

components of the work area (worksurfaces, people, equipment,

etc.) to the same electrical ground point. This point is called the

common point ground. The next step in completing the ground

circuit is to connect the common point ground to the equipment

ground (third wire, green).”

WRONG!

RIGHT

Figure 4. ESD mats should never be grounded in series, that is

daisy chained.