How Do Grounding and Earthing Shoes Work to Prevent ESD?

Electrical Technology

Purpose and Structure of Foot Grounders and Grounding Shoes for Health and ESD Prevention in EPA

In sensitive electronic manufacturing environments, static electricity poses a significant risk to delicate components. Electrostatic discharge (ESD) can damage semiconductors, printed circuit boards (PCBs), and integrated circuits, leading to product failure. To mitigate this, personal grounding methods such as grounding shoes, wrist straps, heel grounders, and static control mats are widely implemented in Electrostatic Protected Areas (EPA). Interestingly, some also claim health benefits from grounding, extending its relevance beyond electronics.

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What Are Grounding / Earthing Shoes?

Grounding or earthing shoes are specially designed footwear that allows the human body to maintain electrical contact with the ground. They are commonly used in:

Electronics manufacturing
Cleanrooms
Research laboratories
ESD-sensitive areas (EPA)

The structure of foot grounders or ESD shoes contain conductive materials (like carbon or copper) in the soles to make an electrical connection with the surface of earth. The purpose of grounding shoes is to provide a path for static electricity to discharge harmlessly to the earth or to a controlled ground point.

Types of Personal Grounding

Personal grounding are used to prevent electrostatic discharge (ESD) damage in electronics by ensuring that the operator and the work surface are at the same electrical potential. Hence, it ensures the sudden flow of electricity that can cause ESD.

Some of the methods of personal grounding include wrist straps, shoe grounders, and static control mats as follow.

ESD Wrist Straps

These are worn on the wrist and connected via a coil cord to a grounded point.
They are considered the most reliable method for grounding stationary personnel.
Common in soldering stations and inspection benches.

Shoe Grounders (Heel/Toe/Full Sole Grounders)

Straps or conductive pads attached to regular footwear.
Work by maintaining electrical contact between the wearer and ESD flooring.
Used in dynamic work environments where wrist straps are impractical.

ESD Footwear

Purpose-built shoes with conductive soles and insoles.
Provide continuous ESD protection throughout movement.
More durable and comfortable than foot grounders.

Static Control Mats

Conductive or dissipative mats placed on floors or work surfaces.
When used in combination with grounders or wrist straps, they help neutralize static charges.

How Do Grounding Shoes Work in EPA?

An ESD protected area (EPA) is a designated space where electrostatic discharge (ESD) is controlled to prevent damage to sensitive electronic components. It’s a defined area where all surfaces, objects, people, and ESD-sensitive devices are kept at the same electrical potential, minimizing the risk of ESD events.

In industries dealing with sensitive electronics, like automotive, aerospace, and electronics manufacturing, ESD can cause damage or malfunction.

In an Electrostatic Protected Area (EPA), grounding shoes serve to equalize electrical potential between the worker and the ground. Here’s how they work:

The conductive sole or foot grounder provides a path for static electricity from the human body to drain safely to ground. In combination with ESD-safe flooring, they maintain a resistance path typically between 10⁵ and 10⁵ ohms, which allows controlled discharge without harmful current flow. This prevents build-up and sudden discharge (ESD) that could damage sensitive electronic components.

Are There Health Benefits Using Grounding Shoes?

Grounding or Earthing is an electrical bond between human body and earth. This practice involves making direct contact with the earth’s surface, like walking barefoot on grass or sand. This process offer a direct electrical connection between the body and the Earth. This connection allows for the transfer of collected electrons in the form of static electricity on the human body to the ground.

Grounding has been linked to potential benefits such as improved sleep, reduced inflammation, and stress reduction, according to the National Institutes of Health (NIH) (Gov).

Claims:
Some advocates argue that grounding (often called earthing) improves human health by:

Reducing inflammation
Improving sleep
Balancing cortisol levels
Lowering stress and anxiety

Scientific Evidence:

Several studies, though limited in scope and peer review, have examined these claims:

Chevalier et al. (2012): Found reduced blood viscosity and cortisol normalization in grounded subjects.
Oschman (2007): Hypothesized health benefits based on the electrical connection between body and Earth.
Ghaly & Teplitz (2004): Claimed improved sleep quality in subjects using grounded sleep systems.

⚠️ Caution: While these studies suggest potential benefits, many are considered preliminary, often lack control groups, and are not widely accepted in mainstream medical literature. Thus, grounding shoes for health remains a developing theory rather than established science.

Meanwhile, the engineering application is well-supported, the health benefits of grounding are still under research and debate. For professionals working in electrical and electronics, special shoes like ESD (Electrostatic Dissipative), EV (Electrical Hazard) and ESR (Electric Shock Resistance), and personal grounding gear are essential tools, not just for compliance, but for product safety and reliability.

Good to Know: In EPA, grounding shoes are scientifically validated for ESD protection. Their health benefits, while intriguing, should be considered supplementary theories pending further credible evidence.

Precautions:

ESD shoes must comply with the ESD Association (ESDA) standards and be tested according to ANSI/ESD STM97.2-2006, in addition to any relevant ASTM standards, when used within an Electrostatic Protected Area (EPA).
Foot grounders and ESD shoes must be worn on both feet to maintain a continuous path to ground, even when one foot is lifted.
Each ESD foot grounder and contact strap should be regularly tested before use and during operation to ensure proper functionality.
Avoid wearing grounding shoes in rainy or stormy weather to reduce the risk of lightning strikes.
While not mandatory, the EN 61340-5-1 standard recommends a minimum resistance to ground (R_G) of 1 MΩ to limit accidental electrical current exposure to no more than 2.5 × 10⁻⁴ amperes (0.00025 A).

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