ANSI/ESD S20.20 vs IEC 61340-5-1: which one applies?

At a glance

	ANSI/ESD S20.20	IEC 61340-5-1
Published by	ESD Association (ANSI approved)	International Electrotechnical Commission
Typical use	Strongest in North America, and used worldwide where customers ask for it	Strongest in Europe, also used in Asia and by sites that align with other IEC and ISO systems
Scope	Any organisation that makes, processes, assembles, installs, packages, labels, services, tests or handles ESD sensitive items	Protection of electronic devices from electrostatic phenomena
Programme documents	An ESD control programme plan and its technical basis	An ESD control programme plan, with requirements for training, compliance verification and technical requirements
Checking compliance	Often third-party certification by an accredited body	Internal verification or third-party certification
Protection level	Items that withstand 100 V human body model, 200 V charged device model and 35 V on isolated conductors	Check the current edition for the exact levels. The 100 V human body figure is the one most often quoted

Limits both standards share

The two standards line up on the main numbers. These are the figures people ask about most. Always confirm against the current edition.

Control	Typical limit
Voltage on a person	Below 100 V when walking, using the flooring and footwear system
Wrist strap system	Below 3.5 x 10^7 ohm (35 megohm), person and strap together
Flooring and footwear system	Below 1 x 10^9 ohm, or body voltage below 100 V
Worksurfaces	Below 1 x 10^9 ohm to ground
Insulators at the workstation	Remove them, or keep them a set distance away from ESD sensitive items (typically 30 cm), or neutralise them with ionisation

Where they differ in practice

S20.20 puts more weight on a documented plan, training records and third-party audits. Many aerospace and defence customers ask for it by name.
IEC 61340-5-1 gives more freedom in how you verify compliance, and fits easily alongside an ISO 9001 quality system.
S20.20 explicitly covers the three protection levels above (human body, charged device and isolated conductors). Check the current edition of IEC 61340-5-1 for its own wording.
Each standard calls up its own supporting test methods, so the same product may be tested slightly differently.

How to choose

Check what your customers write into their purchase orders and audits. If they name a standard, use that one.
Check where you sell. North American customers lean to S20.20. European and many Asian customers lean to IEC 61340-5-1.
Check how you want to prove compliance. If you need an accredited certificate, plan for a third-party audit.
If you sell worldwide, many sites build one programme that meets both.

What this means for your consumables

Wrist straps, cords, mats, footwear, bags, tapes and testers should all be tested to the methods your standard calls up. Ask your supplier for datasheets that state the test method and result. Sucatec can send datasheets for most items on request.

This is a plain-English summary, not the standard. Standards are revised, so check the current edition. Your quality team or auditor decides which one applies to your site.