What is Touch & Step Potential? Risk Reduction for Lightning Explained! ⚡

Here’s our guide on Touch & Step Potential, an essential aspect of Lightning Protection. This video, aligned with the international standard IEC 62305 Part 3, is designed to enhance your understanding of this critical safety topic.

Understanding the Basics:
The video begins with the basics of electrical energy movement through conductive objects. Scenarios like a broken utility pole or a fallen overhead conductor can turn everyday objects like metal fences, wet soil, or puddles into dangerous conductors of electricity. We explore how these seemingly innocuous items can become high-voltage zones due to various factors like electrical potential, resistance, and soil conditions.
This section emphasizes the 'ground potential gradient' concept, elucidating how voltage dissipates from a grounded object and the resultant ground potentials. We liken the voltage dissipation to ripples created by a stone in a pond, where the voltage is highest at the source and diminishes with distance.

What will you learn about Step & Touch Potential?
We delve into the concept of Step Potential, a critical safety concern in electrical engineering. Imagine an overhead conductor impacting a chain-link fence or the ground, creating a high-voltage condition. The resulting voltage gradient in the soil can cause a voltage difference between two points on the ground - a phenomenon we refer to as Step Potential. This segment highlights the dangers posed by this voltage difference, particularly the risk of fatal electrical currents passing through the body.
Moving on to Touch Potential, we define it as the voltage difference between two points on the body, such as hand-to-hand or hand-to-foot. We use practical examples like touching an electrified fence to illustrate how this potential can result in dangerous currents flowing through the body.

Potential Control in Structures:
The video then addresses the importance of potential control in densely populated areas near electrical structures. We discuss how to assess the adequacy of potential control measures based on the resistance gradient of the earth's surface. The role of ring earth electrodes in creating a potential control system is explained, along with guidelines on the required number of rings based on distance from the structure.

Risk Reduction Strategies:
To reduce the risks associated with Touch & Step Potential, we recommend several steps:
1. Covering the down conductor with a suitable insulating material.
2. Ensuring a minimum contact resistance around the down conductors.
3. Applying layers of insulating materials like asphalt or gravel to mitigate risks.
4. Employing potential control to optimize the earthing system.
We stress the need for a Rise of Earth Potential Study to identify hazards and discuss how an Electrical Engineer can effectively mitigate these risks.

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0:00 Introduction
1:40 What is Ground Potential Gradient?
2:16 What is Step Potential?
2:57 What is Touch Potential?
3:41 What is Potential Control?
4:44 How to reduce risk cause by Touch & Step Potential?
5:11 Step 1) Down Conductor Insulation
5:29 Floor Layer's Contact Resistance
5:43 Adding Insulating Material
5:58 Potential Control

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