{"id":1481,"date":"2026-09-14T08:05:00","date_gmt":"2026-09-14T00:05:00","guid":{"rendered":"https:\/\/www.han-sphere.com\/?p=1481"},"modified":"2026-09-01T15:36:59","modified_gmt":"2026-09-01T07:36:59","slug":"high-voltage-pcb-clearance","status":"publish","type":"post","link":"https:\/\/www.han-sphere.com\/ru\/blog\/news\/high-voltage-pcb-clearance\/","title":{"rendered":"High Voltage PCB Clearance Rules Every Designer Must Follow"},"content":{"rendered":"

Designing a printed circuit board (PCB) for high voltage applications presents unique challenges. Unlike low-voltage circuits, high voltage designs are susceptible to arcing, parasitic capacitance, and insulation breakdown if not properly managed. Among the most critical design parameters are clearance<\/strong> \u0438 creepage<\/strong> distances. Understanding and applying the correct high voltage PCB clearance rules is essential for ensuring product safety, reliability, and compliance with international standards such as IEC 60950 and IPC-2221.<\/p>\n

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What is PCB Clearance?<\/h2>\n

In the context of PCB design, clearance is defined as the shortest distance through the air between two conductive parts (like \u043f\u0440\u043e\u043a\u043b\u0430\u0434\u043a\u0438 \u0434\u043b\u044f \u0434\u0435\u0442\u0430\u043b\u0435\u0439<\/a> \u0438\u043b\u0438 \u043c\u0435\u0434\u043d\u044b\u0435 \u0441\u043b\u0435\u0434\u044b<\/a>). High voltage can cause air to ionize and become conductive, leading to an electrical arc between these conductors if they are too close. The breakdown voltage of air is approximately 3kV per millimeter, though this can vary significantly based on environmental factors like humidity, temperature, and atmospheric pressure.<\/p>\n

When designing high voltage circuits, maintaining adequate PCB clearance prevents arcing. This is particularly crucial for safety-critical applications like medical devices, automotive electronics, and industrial power supplies. The required clearance depends not only on the peak working voltage but also on the operating environment and the pollution degree.<\/p>\n

Creepage vs. Clearance: What is the Difference?<\/h2>\n

While clearance is the shortest distance through the air, creepage<\/strong> is the shortest distance along the surface of the insulating material (the PCB substrate) between two conductive parts. High voltage PCB clearance and creepage are related but distinct concepts.<\/p>\n

Creepage is critical because the surface of a PCB can become contaminated with dust, moisture, or other conductive particles over time (a concept measured by the pollution degree). These contaminants can create a conductive path across the dielectric surface, leading to a phenomenon known as tracking. Tracking can eventually carbonize the substrate, creating a permanent short circuit and posing a severe fire hazard.<\/p>\n

Because creepage must follow the contours of the surface, it is always equal to or greater than the clearance distance. When the required creepage distance cannot be achieved on a flat board surface, designers often use techniques like milling slots or V-grooves between high voltage nodes to increase the surface distance without changing the physical layout.<\/p>\n

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Key Safety Standards for High Voltage PCB Design<\/h2>\n

Several international standards dictate the minimum high voltage PCB clearance and creepage requirements. Some of the most widely referenced standards include:<\/p>\n