If you’ve been handling ElectroStatic Discharge (ESD) sensitive devices for a while, you’ve probably come across the various ESD symbols already. But do you know the difference(s) and when to use them?

If you are new to ESD protection or have just taken over responsibility for an existing ESD program, this is where to start!

Introduction

The ESD Standard ANSI/ESD S20.20 requires that “ESDS items, system or packaging marking shall be in accordance with customer contracts, purchase orders, drawing or other documentation.” [ANSI/ESD S20.20 clause 8.5 Marking]. If ESD sensitive items are not covered in any of these documents, each company has to decide whether marking is required. If it is deemed necessary, the ESD Control Program Plan needs to define the details.

ESD Susceptibility Symbol

The ESD Susceptibility Symbol is the most commonly known symbol which consists of a yellow hand in the act of reaching, deleted by a bar; all within a black triangle. It is intended to identify devices and assemblies that are susceptible to ESD.

When to use the ESD Susceptibility Symbol:

The ESD Susceptibility Symbol is correctly used as follows:

• on individual components and related documents to state: ‘this device is static sensitive; do not touch without appropriate precautions’
• on assemblies and related documents to state: ‘includes static sensitive components; take appropriate precautions’
• as part of a sign identifying an area where sensitive devices are handled; to warn all who approach it that precautions are required

 

Color of the ESD Susceptibility Symbol

The color is optional except “the color red shall not be used because it suggests a hazard to personnel.” [ANSI/ESD S8.1 clause 4.2.1 color].

Normally, the hand and slash symbol is used on a black triangle on a yellow or orange background.

ESD Protective Symbol

Just like the ESD Susceptibility Symbol, the ESD Protective Symbol has a reaching hand in a triangle. However, note the arc and missing slash through the triangle! Because of these differences it has a very different meaning.

This symbol should be on ESD protective products identifying a specialty product that has at least one ESD control property.

The ESD Protective Symbol is also called the ESD Packaging Symbol.

If a letter is under the triangle, it should identify the most important ESD control property:

• L = Low Charging
• D = Static Dissipative
• C = Conductive EPA (for use in the ESD Protected Area)

When to use the ESD Protective Symbol

The ESD Protective Symbol may be used to identify items that possess at least one ESD control property:

• Low Charging (formerly referred to as astatic or antistatic)
• Resistance (Conductive or Static Dissipative) able to remove electrostatic charges when grounded
• Discharge Shielding

Color of the ESD Protective Symbol

The color is optional except “the color red shall not be used because it suggests a hazard to personnel.” [ANSI/ESD S8.1 clause 5.2.1 color].

Normally, a hand symbol is used on a black triangle on a yellow background.

ESD Common Ground Point and Earth Bonding Point Symbols

These two symbols identify where all ESD elements at an ESD workstation should be connected. There is a newer and older symbol; they are very different but basically have the same meaning:

• The Earth Bonding Point Symbol has the earth ground symbol and concentric circles around the ground snap, plug or jack. This is the older symbol.
• The ESD Common Ground Point Symbol has concentric circles with thick circle around the ground snap, plug or jack. This is the newer symbol.

Both symbols should include text identification.

 

ESD Common Ground Point (newer symbol) and Earth Bonding Point (older symbol) 

Color of the ESD Common Ground Point and Earth Bonding Point Symbols

The color is optional except “the color red shall not be used because it suggests a hazard to personnel.” [ANSI/ESD S8.1 clause 5.2.1 color].

Conclusion

The ESD Standard S20.20 recommends that every organisation handling ESD sensitive items marks their products using the above 3 symbols for every. Correct use of markings will “indicate that an item or material is ESD susceptible and those that indicate that an item is designed to afford some degree of ESD protection.” [ANSI/ESD S8.1 clause 1.1 Purpose]

Symbol artwork for all of the above symbols can be downloaded at no charge from the ESD Association.