What is the safety distance between people and high voltage? -Solutions - Huaqiang Electronic Network
1. Safe Distance - When you come across high-voltage lines in the wild, it's crucial to stay far away. The farther, the safer. For example: 10kV and below – 0.70m; 20kV, 35kV – 1.00m; 66kV, 110kV – 1.50m; 220kV – 3.00m; 330kV – 4.00m; 500kV – 5.00m (based on State Grid Corporation’s “Electric Safety Work Regulations†for power lines).
The minimum vertical distance between 220kV overhead transmission lines and buildings is 6 meters, while the side conductor-to-building distance should be at least 5 meters. According to regulations, this refers to the horizontal distance between the conductor and urban multi-story or planned buildings.
Electromagnetic radiation from a 220kV line can exceed 0.4 microtesla within 100 meters. Experts consider 0.4 microtesla as the safety threshold for magnetic fields generated by high-voltage lines. Exceeding this level may pose health risks, especially to children.
Safety is relative. Prolonged exposure, even at low levels, can cause harm over time.
2. How to Identify Voltage Levels – A professional way to determine the voltage level is by observing the tower structure, wires, and insulators. In Beijing, the easiest method is checking the tower markings:
- Written as "50XX" = 500kV
- "22XX" = 220kV
- "11X" = 110kV
- "3X" = 35kV
Among these, 35kV lines are considered more dangerous, especially in areas like Mentougou, Haidian, Miyun, and Huairou, where some 35kV lines are grounded. This makes them more hazardous than higher voltage lines.
3. Changes in Safety Distance – The above distances apply under normal conditions, but real-life situations can be more complex. For instance, tall trees, narrow mountain passes, or human actions like flying kites, throwing fishing rods, or climbing towers can increase risk. Even small objects like trekking poles can become dangerous if they touch live wires.
Special cases include broken wires, lightning strikes, or grounding issues. Weather changes also play a role. Professionals must always remain alert.
4. Electric Shock Process – High-voltage electricity can affect people in various ways:
- Impact (e.g., falling from a height without burning)
- Electric shock (similar to lightning, causing burns or holes in the body)
- Long-term exposure can lead to severe burns
In Beijing, high-voltage lines are usually far from populated areas, and most 110kV lines have relay protection that cuts off power within 1 second of a shock. However, 35kV and lower lines, due to their neutral grounding system, do not trigger automatic disconnection, making them more dangerous if someone remains in contact.
5. Identifying Electric Shock – While high-voltage electricity is dangerous, it's not necessarily more dangerous than low-voltage. In Beijing, deaths from 10,000V, 6,000V, 380V, and 220V are common. Fewer fatalities occur at higher voltages because of better safety measures. However, 10kV and below are the most deadly.
High-voltage lines are generally safe when walked around normally. Scientific research has debunked claims about electromagnetic radiation, and environmental agencies confirm that such lines are not harmful under normal conditions. Some real estate developers may spread misinformation to create fear among residents.
But still, be cautious:
- Avoid actions that could cause tip discharges, such as climbing or raising metal objects (e.g., trekking poles, fishing rods, kite strings)
- Watch out for special terrain like narrow mountain passes or tall trees near power lines
- Be aware of unusual signs: humming sounds, halos around hats or fingers, or sparks from sharp parts (common in substations)
If you notice any of these signs, don't panic or run. Avoid stepping voltage, and don’t attempt to rescue others unless you're using an insulated object. Stay calm, identify the direction of the high-voltage line, and slowly move backward in small steps. If possible, use long insulating tools to assist others safely.
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