电气间隙和爬电距离 | 规则和计算 / 影响因素 / 常见错误

注：本文为 “电气间隙和爬电距离 | 规则和计算” 相关文章合辑。

英文引文，机翻，未校。
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Clearance and Creepage Distances: Rules and Calculation

电气间隙和爬电距离：规则和计算

EMS 19 September 2024 12:51 am

Understanding Clearance and Creepage Distances

了解电气间隙和爬电距离

When designing electrical equipment, ensuring the safety and reliability of the system is paramount. Two critical factors that play a vital role in maintaining the integrity of electrical insulation are clearance and creepage distances. These distances help prevent electrical breakdown, flashover, and tracking between conductive parts at different potentials.

在设计电气设备时，确保系统的安全性和可靠性至关重要。在保持电气绝缘完整性方面起着至关重要作用的两个关键因素是电气间隙和爬电距离。这些距离有助于防止不同电位的导电部件之间的电击穿、闪络和电痕。

What is Clearance Distance?

什么是间隙距离？

Clearance distance is the shortest distance through air between two conductive parts or between a conductive part and the grounding surface. It is a measure of the insulation’s ability to withstand electric stress without breakdown. The clearance distance is influenced by factors such as the voltage level, altitude, and the type of insulation material used.

间隙距离是两个导电部件之间或导电部件与接地表面之间通过空气的最短距离。它是衡量绝缘层承受电应力而不击穿的能力的指标。间隙距离受电压等级、海拔高度和所用绝缘材料类型等因素的影响。

What is Creepage Distance?

什么是爬电距离？

Creepage distance, on the other hand, is the shortest distance along the surface of an insulating material between two conductive parts or between a conductive part and the grounding surface. It is a measure of the insulation’s ability to resist tracking and surface flashover. The creepage distance is affected by factors such as the voltage level, the degree of pollution, and the insulation material’s surface properties.

另一方面，爬电距离是两个导电部件之间或导电部件与接地表面之间沿绝缘材料表面的最短距离。它是衡量绝缘材料抵抗电痕和表面闪络能力的指标。爬电距离受电压等级、污染程度和绝缘材料表面特性等因素的影响。

Importance of Clearance and Creepage Distances

间隙和爬电距离的重要性

Maintaining adequate clearance and creepage distances is essential for several reasons:

保持足够的电气间隙和爬电距离至关重要，原因如下：

1. Safety: Proper clearance and creepage distances prevent electrical accidents by ensuring that there is sufficient insulation between conductive parts at different potentials.

   安全性：适当的间隙和爬电距离通过确保不同电位的导电部件之间有足够的绝缘来防止电气事故。

2. Reliability: Adequate distances help prevent insulation breakdown and surface tracking, which can lead to equipment failure and downtime.

   可靠性：足够的距离有助于防止绝缘击穿和表面跟踪，这可能导致设备故障和停机。

3. Compliance: Adhering to the required clearance and creepage distances ensures that the electrical equipment complies with relevant safety standards and regulations.

   合规性：遵守所需的间隙和爬电距离可确保电气设备符合相关的安全标准和法规。

Factors Affecting Clearance and Creepage Distances

影响电气间隙和爬电距离的因素

Several factors influence the determination of clearance and creepage distances:

有几个因素会影响电气间隙和爬电距离的确定：

Voltage Level

电压等级

The voltage level is a primary factor in determining the required clearance and creepage distances. Higher voltages demand greater distances to prevent electrical breakdown and flashover.

电压电平是确定所需间隙和爬电距离的主要因素。电压越高，距离越远，以防止电气击穿和闪络。

Altitude

高度

Altitude affects the air density and, consequently, the insulation’s dielectric strength. At higher altitudes, the air is less dense, and the clearance distance must be increased to maintain the same level of insulation.

海拔高度会影响空气密度，从而影响绝缘材料的介电强度。在较高的海拔高度，空气密度较低，必须增加间隙距离以保持相同的绝缘水平。

Pollution Degree

污染程度

The degree of pollution in the environment impacts the creepage distance. In polluted environments, conductive particles can accumulate on insulating surfaces, reducing the effective creepage distance. To compensate for this, the creepage distance must be increased based on the expected pollution level.

环境中的污染程度会影响爬电距离。在污染环境中，导电颗粒会积聚在绝缘表面上，从而减小有效爬电距离。为了补偿这一点，必须根据预期的污染水平增加爬电距离。

Insulation Material

绝缘材料

The type of insulation material used affects both clearance and creepage distances. Materials with higher dielectric strength can withstand greater electric stress, allowing for smaller clearance distances. Similarly, materials with better surface properties, such as hydrophobicity and resistance to tracking, can have shorter creepage distances.

使用的绝缘材料类型会影响电气间隙和爬电距离。介电强度较高的材料可以承受更大的电应力，从而允许更小的间隙距离。同样，具有更好表面特性（例如疏水性和抗电痕性）的材料可以具有更短的爬电距离。

Standards and Guidelines for Clearance and Creepage Distances

电气间隙和爬电距离的标准和准则

To ensure the safety and reliability of electrical equipment, various standards and guidelines provide recommendations for clearance and creepage distances. Some of the key standards include:

为确保电气设备的安全性和可靠性，各种标准和指南都提供了有关电气间隙和爬电距离的建议。一些关键标准包括：

1. IEC 60664-1: This international standard provides guidelines for determining clearance and creepage distances in low-voltage equipment.

   IEC 60664-1：该国际标准为确定低压设备中的电气间隙和爬电距离提供了指南。

2. UL 840: This standard, published by Underwriters Laboratories, covers the safety requirements for insulation coordination, including clearance and creepage distances.

   UL 840：该标准由 Underwriters Laboratories 发布，涵盖了绝缘协调的安全要求，包括电气间隙和爬电距离。

3. IPC-2221: This standard, developed by the Institute for Printed Circuits, provides guidelines for designing printed circuit boards, including recommendations for clearance and creepage distances.

IPC-2221：该标准由印刷电路研究所制定，提供了设计印刷电路板的指南，包括间隙和爬电距离的建议。

These standards take into account factors such as voltage level, pollution degree, and insulation material to provide minimum required distances for various applications.

这些标准考虑了电压水平、污染程度和绝缘材料等因素，为各种应用提供所需的最小距离。

Calculating Clearance and Creepage Distances

计算间隙和爬电距离

To determine the appropriate clearance and creepage distances for a given application, designers can follow these steps:

要确定给定应用的适当间隙和爬电距离，设计人员可以按照以下步骤作：

1. Identify the voltage level: Determine the maximum voltage that will be present between the conductive parts.

   确定电压水平：确定导电部件之间将存在的最大电压。

2. Consider the altitude: If the equipment will be used at high altitudes, adjust the clearance distance accordingly.

   考虑海拔高度：如果设备将在高海拔地区使用，请相应地调整间隙距离。

3. Assess the pollution degree: Evaluate the environment in which the equipment will be used and determine the expected level of pollution.

   评估污染程度：评估设备将使用的环境并确定预期的污染水平。

4. Select the insulation material: Choose an insulation material that meets the requirements for dielectric strength and surface properties.

   选择绝缘材料：选择满足介电强度和表面特性要求的绝缘材料。

5. Consult the relevant standards: Refer to the appropriate standards and guidelines for the minimum required clearance and creepage distances based on the above factors.

   查阅相关标准：请参阅相应的标准和指南，了解基于上述因素所需的最小电气间隙和爬电距离。

6. Apply safety margins: To account for manufacturing tolerances and other uncertainties, apply appropriate safety margins to the calculated distances.

   应用安全边际：要考虑制造公差和其他不确定性，请对计算的距离应用适当的安全边际。

Here’s an example of how to calculate the clearance and creepage distances for a given scenario:

以下是如何计算给定场景的电气间隙和爬电距离的示例：

Suppose we have a printed circuit board (PCB) with a maximum voltage of 250V AC, operating in a moderately polluted environment (pollution degree 2) at an altitude of 2000m. The insulation material used is FR-4, a common PCB material.

假设我们有一块最大电压为 250V AC 的印刷电路板 （PCB），在海拔 2000m 的中度污染环境（污染等级 2）中运行。使用的绝缘材料是 FR-4，一种常见的 PCB 材料。

Using IPC-2221 as the reference standard, we can find the minimum required clearance and creepage distances:

使用 IPC-2221 作为参考标准，我们可以找到所需的最小间隙和爬电距离：

However, since the PCB will be used at an altitude of 2000m, we need to adjust the clearance distance. According to IPC-2221, for altitudes between 1000m and 3000m, the clearance distance should be multiplied by a factor of 1.48. Therefore, the adjusted clearance distance becomes:

但是，由于 PCB 将在 2000m 的海拔高度使用，因此我们需要调整间隙距离。根据 IPC-2221，对于 1000m 到 3000m 之间的海拔高度，间隙距离应乘以 1.48 倍。因此，调整后的间隙距离变为：

Adjusted Clearance = 1.25mm × 1.48 = 1.85mm

调整后的间隙 = 1.25 毫米 × 1.48 = 1.85 毫米

In this example, the minimum required clearance distance is 1.85mm, and the minimum creepage distance is 2.5mm. Designers should ensure that the PCB layout maintains these distances between conductive parts to ensure the safety and reliability of the board.

在此示例中，所需的最小间隙距离为 1.85mm，最小爬电距离为 2.5mm。设计人员应确保 PCB 布局在导电部件之间保持这些距离，以确保电路板的安全性和可靠性。

Common Mistakes and Best Practices

常见错误和最佳实践

When designing for clearance and creepage distances, there are some common mistakes to avoid and best practices to follow:

在设计间隙和爬电距离时，需要避免一些常见错误并遵循最佳实践：

Common Mistakes

常见错误

1. Underestimating the voltage level: Failing to consider the maximum possible voltage, including transient overvoltages, can lead to insufficient clearance and creepage distances.

   低估电压电平：不考虑最大可能电压，包括瞬态过电压，可能导致电气间隙和爬电距离不足。

2. Neglecting the effect of altitude: Not adjusting the clearance distance for high-altitude applications can result in inadequate insulation.

   忽视海拔的影响：不调整高海拔应用的间隙距离会导致绝缘不足。

3. Ignoring the pollution degree: Failing to account for the environment’s pollution level can lead to insufficient creepage distances and increased risk of tracking.

   忽视污染程度：不考虑环境的污染水平会导致爬电距离不足和漏电跟踪风险增加。

Best Practices

最佳实践

1. Use conservative estimates: When in doubt, use more conservative values for voltage levels, pollution degree, and other factors to ensure a margin of safety.

   使用保守估计值：如有疑问，请对电压水平、污染程度和其他因素使用更保守的值，以确保安全边际。

2. Consider the end-use environment: Evaluate the expected operating conditions and choose appropriate insulation materials and distances accordingly.

   考虑最终使用环境：评估预期的作条件并相应地选择合适的绝缘材料和距离。

3. Verify the design: Use simulation tools and physical testing to validate that the designed clearance and creepage distances are adequate.

   验证设计：使用仿真工具和物理测试来验证设计的间隙和爬电距离是否足够。

4. Follow the standards: Adhere to the relevant standards and guidelines for your application to ensure compliance and safety.

   遵循标准： 遵守您的应用的相关标准和准则，以确保合规性和安全性。

By avoiding common mistakes and following best practices, designers can create electrical equipment that is safe, reliable, and compliant with industry standards.

通过避免常见错误并遵循最佳实践，设计人员可以创建安全、可靠且符合行业标准的电气设备。

FAQ

1. What is the difference between clearance and creepage distance?

   Clearance distance is the shortest distance through air between two conductive parts, while creepage distance is the shortest distance along the surface of an insulating material between two conductive parts.

   电气间隙和爬电距离有什么区别？ 电气间隙是两个导电部件之间通过空气的最短距离，而爬电距离是两个导电部件之间沿绝缘材料表面的最短距离。

2. Why are clearance and creepage distances important?

   Clearance and creepage distances are important for ensuring the safety and reliability of electrical equipment by preventing electrical breakdown, flashover, and tracking between conductive parts at different potentials.

   为什么电气间隙和爬电距离很重要？ 电气间隙和爬电距离对于确保电气设备的安全性和可靠性非常重要，可以防止不同电位的导电部件之间的电气击穿、闪络和漏电起痕。

3. What factors influence the determination of clearance and creepage distances?

   The main factors that influence clearance and creepage distances are voltage level, altitude, pollution degree, and insulation material properties.

   哪些因素会影响电气间隙和爬电距离的确定？ 影响电气间隙和爬电距离的主要因素是电压等级、海拔高度、污染程度和绝缘材料特性。

4. Which standards provide guidelines for clearance and creepage distances?

   Some of the key standards that provide guidelines for clearance and creepage distances include IEC 60664-1, UL 840, and IPC-2221.

   哪些标准提供了电气间隙和爬电距离的指南？ 提供电气间隙和爬电距离指南的一些关键标准包括 IEC 60664-1、UL 840 和 IPC-2221。

5. How can designers ensure that their electrical equipment meets the required clearance and creepage distances?

   Designers can ensure that their equipment meets the required distances by identifying the voltage level, considering the altitude and pollution degree, selecting appropriate insulation materials, consulting relevant standards, applying safety margins, and verifying the design through simulation and testing.

   设计人员如何确保其电气设备满足所需的电气间隙和爬电距离？ 设计人员可以通过识别电压水平、考虑海拔高度和污染程度、选择合适的绝缘材料、查阅相关标准、应用安全裕度以及通过仿真和测试验证设计来确保他们的设备满足所需的距离。

电气间隙和爬电距离

2020-04-23 10:28 CNZHIQIANG

电气间隙是指在两个导电零部件之间或导电零部件与设备防护界面之间测得的最短空间距离。即在保证电气性能稳定和安全的情况下，通过空气能实现绝缘的最短距离。

1、爬电距离

沿绝缘表面测得的两个导电零部件之间或导电零部件与设备防护界面之间的最短路径。即在不同的使用情况下，由于导体周围的绝缘材料被电极化，导致绝缘材料呈现带电现象。此带电区（导体为圆形时，带电区为环形）的半径，即为爬电距离 [1] 。

在绝缘材料表面会形成泄漏电流路径。若这些泄漏电流路径构成一条导电通路，则出现表面闪络或击穿现象。绝缘材料的这种变化需要一定的时间，它是由长时间加在器件上的工作电压所引起的，器件周围环境的污染能加速这一变化。

因此在确定端子爬电距离时要考虑工作电压的大小、污染等级及所运用的绝缘材料的抗爬电特性。根据基准电压、污染等级及绝缘材料组别来选择爬电距离。基准电压值是从供电电网的额定电压值推导出来的。

2、电气间隙 Clearance

电气间隙的大小和老化现象无关。电气间隙能承受很高的过电压，但当过电压值超过某一临界值后，此电压很快就引起电击穿，因此在确认电气间隙大小的时候必须以设备可能会出现的最大的内部和外部过电压（脉冲耐受电压为依据）。在不同场合使用同一电气设备或运用过电压保护器时所出现的过电压大小各不相同。

设定步骤

一般选型是按以下步骤进行

确定电气间隙

确定工作电压峰值和有效值；

确定设备的供电电压和供电设施类别 ；

根据过电压类别来确定进入设备的瞬态过电压大小；

确定设备的污染等级（一般设备为污染等级 2）；

确定电气间隙跨接的绝缘类型（功能绝缘、基本绝缘、附加绝缘、加强绝缘）。

确定爬电距离

确定工作电压的有效值或直流值；

确定材料组别（根据相比漏电起痕指数，其划分为：Ⅰ 组材料，Ⅱ 组材料，Ⅲa 组材料，Ⅲb 组材料。注：如不知道材料组别，假定材料为 Ⅲb 组）；

确定污染等级；

确定绝缘类型（功能绝缘、基本绝缘、附加绝缘、加强绝缘）。

定电气间隙值

根据测量的工作电压及绝缘等级，查表（ 4943：2H 和 2J 和 2K，60065-2001 表：表 8 和表 9 和表 10） 检索所需的电气间隙即可决定距离；作为电气间隙替代的方法，4943 使用附录 G 替换，60065-2001 使用附录 J 替换。

GB 8898-2001：电气间隙考虑的主要因素是工作电压，查图 9 来确定。（对和电压有效值在 220-250V 范围内的电网电源导电连接的零部件，这些数值等于 354V 峰值电压所对应的那些数值：基本绝缘 3.0mm , 加强绝缘 6.0mm）。

定爬电距离值

根据工作电压、绝缘等级及材料组别，确定爬电距离数值，如工作电压数值在表两个电压范围之间时，需要使用内差法计算其爬电距离。

GB 8898-2001 其判定数值等于电气间隙，如满足下列三个条件，电气间隙和爬电距离加强绝缘可减少 2mm，基本绝缘可减少 1mm：

1）这些爬电距离和电气间隙会受外力而减小，但它们不处在外壳的可触及导电零部件与危险带电零部件之间；

2）它们靠刚性结构保持不变；

3）它们的绝缘特性不会因设备内部产生的灰尘而受到严重影响。

• 注意：但直接与电网电源连接的不同极性的零部件间的绝缘，爬电距离和电气间隙不允许减小。基本绝缘和附加绝缘即使不满足爬电距离和电气间隙的要求，只要短路该绝缘，设备仍满足标准要求，则是可以接受的（8898 中 4.3.1 条）。

• GB 4943 中只有功能绝缘的电气间隙和爬电距离可以减小，但必须满足 标准 5.3.4 规定的高压或短路试验。

注意事项

1）可动零部件应使其处在最不利的位置；

2）爬电距离值不能小于电气间隙值；

3）承受了机械应力试验 [3]

爬电距离与电气间隙

吉孟雷已于 2024-07-23 16:13:33 修改

1、爬电距离 (Creepage distance) 的定义

爬电距离是沿绝缘表面测得的两个导电零部件之间或导电零部件与设备防护界面之间的最短路径。即在不同的使用情况下，由于导体周围的绝缘材料被电极化，导致绝缘材料呈现带电现象。

2、电气间隙（air clearance）的定义

电气间隙是指在两个导电零部件之间或导电零部件与设备防护界面之间测得的最短空间距离。即在保证电气性能稳定和安全的情况下，通过空气能实现绝缘的最短距离。

3、简单理解爬电距离与电气间隙

爬的意思，可以看做一个蚂蚁从一个带电体走到另一个带电体的必须经过最短的路程，就是爬电距离。

电气间隙，是一个带翅膀的蚂蚁，飞的最短距离。

4、举例

从下图可以看出

1 > 电气间隙与挖槽的长度是没有关系的。

2 > 槽宽小于 1mm 不影响爬电距离，槽宽大于 1mm，影响爬电距离。

图：爬电距离和电气间隙的理解示意图

5、导线过流能力与线宽的关系

img

图：导线线宽和过流能力关系对照表

一般我们常用的 35um 铜厚 1oz 时，线宽 0.5mm 过 1A 左右电流，1mm 线宽过 2A，2mm 线宽过 4A 电流，近似过流能力是线宽的 2 倍左右。

6、爬电距离与电气间隙的安规要求

从下图的对比看，同样电压的情况下电气间隙的距离要比爬电距离要求距离更近一点。

图：安规要求中的爬电距离和电气间隙

via:

• Clearance and Creepage Distances: Rules and Calculation - EMS
  https://electronicmanufacturingservice.org/clearance-and-creepage-distances-rules-and-calculation/

• 电气间隙和爬电距离 - CNZHIQIANG - 博客园
  https://www.cnblogs.com/zhiqiang_zhang/p/12759017.html

• 爬电距离与电气间隙-CSDN博客
  https://blog.csdn.net/weixin_38345163/article/details/125289875

• 电气间隙和爬电距离的算法_2023-10-27 12:03 发布于：山西省
  https://www.sohu.com/a/731685400_121123772