Q: Are ESD shoes and Conductive shoes the same thing?
A: There are two types of ESD shoes, Static Dissipative and Static Conductive.
The Static Conductive shoe will guarantee a combined resistance of personnel and footwear of less than 1.0E6 Ohms. I have a pair of Static Conductive shoes that when I’m standing on a static conductive flooring system (2.5E4 Ω to 1.0E6 Ω), my combined resistance from my body through the ESD footwear and through the ESD conductive flooring system to electrical ground or earth is less than 1.0E6 ohms per DoD 4145.26-M, C18.104.22.168.1: “The maximum resistance of a body, plus the resistance of conductive shoes, plus the resistance of the floor to the ground system shall not exceed 1,000,000 ohms total”… “The contractor can set the maximum resistance limits for the floor to the ground system and for the combined resistance of a person’s body plus the shoes, as long as the total resistance does not exceed 1,000,000 ohms.”
This Static Conductive shoe is typically used for electrical safety requirements for facilities that deal with explosive environments such as ordinance, munitions, explosive powders, flammable liquids, etc. This is outside of the realm of ANSI/ESD S20.20-2007 and MIL-HDBK-263B.
If you’re goal is the protection of static sensitive devices, then Static dissipative shoes on a static conductive flooring system or a static dissipative flooring system will suffice so long as the combined resistance of personnel, footwear, and flooring to electrical or earth ground is less than 3.5E7 Ω as per ANSI/ESD STM97.1-2006. In that case, a good static dissipative shoe will be more than 1.0E6 or a meg ohm, but the resistance will probably be less than 35 Meg ohms. The best way to measure the footwear is to have personnel wear them for at least 10 minutes prior to going to the tester and checking for pass/fail low/fail high, as that’s the most practical way to test them. You can measure the resistance of the shoe from insole to outsole, but they aren’t used that way on the ESD flooring system. The ESD shoe relies on sweat from the personnel that wears them.
My combined resistance from my body, through my Static Conductive HK-4327-TN (men’s) or Static Dissipative SH-4341-WH shoes and through a static conductive floor to electrical/earth ground is about 1.6E6 Ω.