One Step Could Be Fatal: The Electrical Hazard Most People Ignore

"One Step Could Be Fatal: The Electrical Hazard Most People Ignore"

by Ohm Engineering Works | May 06, 2025 | Electric Company

When it comes to high-voltage electrical systems—especially in substations, switchyards, and transmission line environments—safety isn’t just a practice; it’s a lifesaving science. Among the most critical yet often misunderstood aspects of electrical safety are two powerful hazards: Step Potential and Touch Potential.

Whether you’re an electrical engineer, safety officer, technician, or simply someone working near high-voltage infrastructure, understanding these electrical dangers is vital for preventing serious injuries or fatalities.

What Is Step Potential?

Step Potential refers to the voltage difference between two points on the ground that are one step apart (typically about 1 meter or 3 feet), experienced when a fault current flows into the earth.

Why Is It Dangerous?

Imagine a person standing on soil during a ground fault event, such as a lightning strike or equipment failure. The earth near the faulted point will develop voltage gradients. If each foot is on a spot with a different voltage potential, the human body can act as a conductor, allowing electricity to pass up one leg and down the other. The result? Severe electric shock or even cardiac arrest.

What Is Touch Potential?

Touch Potential is the voltage difference between a grounded conductive object (like a metal fence or equipment housing) and the ground surface where a person stands.

How It Becomes Fatal

If someone touches a grounded structure during a fault condition while standing on electrified ground, their body forms a bridge between two different voltage potentials—the structure (zero or near-zero potential) and the earth (high potential). This can cause dangerous currents to pass through the body, often involving the heart.

Where Do These Hazards Occur?

Step and touch potentials are especially hazardous in:

• High-voltage substations

• Transmission line towers

• Transformer yards

• Lightning-prone zones

• Earthing systems near power equipment

Even a single ground fault can create dangerous conditions that extend several meters from the fault location.

Real-World Accidents: Why It Matters

There have been countless cases worldwide where personnel suffered severe burns or fatalities due to unmanaged step or touch voltages—especially when standing barefoot or working near inadequately grounded equipment. Awareness, proper design, and maintenance could have saved many of these lives.

How to Mitigate Step and Touch Potential Risks

Ensuring electrical safety in such environments demands multi-layered mitigation strategies. Here are proven techniques:

1. Proper Grounding and Grid Design

Designing a grounding grid with closely spaced conductors reduces surface voltage gradients and equalizes potentials. This forms the foundation of protection in substations.

2. Gravel or Crushed Rock Surfacing

Installing a thick layer of gravel or crushed stone increases surface resistance, significantly reducing step potential by preventing direct contact with the energized earth.

3. Equipotential Bonding

Ensure all exposed conductive parts are bonded together and grounded so there’s no potential difference between them during fault conditions.

4. Maintaining Safe Approach Distances

Restricting access to areas near grounding systems or energized structures during fault events can prevent unintentional exposure to lethal voltage differentials.

5. Insulated Mats and Footwear

Using electrically insulating materials in high-risk zones further limits the chance of current flowing through the human body.

Standards & Guidelines

Several international and national standards cover grounding system design and safety measures:

• IEEE Std 80 – Guide for Safety in AC Substation Grounding

• IEC 61936-1 – Power installations exceeding 1 kV AC

• IS 3043:2018 – Indian Standard for Earthing

These standards define acceptable limits of step and touch voltages and provide design criteria to ensure personnel safety.

Why Should Everyone in Electrical Operations Understand This?

Because electrical safety isn’t just the responsibility of engineers—it belongs to everyone working near live equipment. When something goes wrong, it happens in milliseconds. Knowledge of step and touch potential can:

• Prevent injuries

• Save lives

• Ensure compliance with safety standards

• Reduce downtime and liability in power-intensive operations

Conclusion: Awareness is the First Layer of Protection

Step and touch potential may be invisible, but their impact is deadly if ignored. Understanding these hazards is not just a technical necessity—it’s a human responsibility.

So whether you're designing a substation, training a maintenance crew, or walking near a grounded structure during a storm—respect the ground beneath your feet and the metal you touch.

Share this article with your team, peers, or safety circles—because awareness leads to action, and action saves lives