邯郸电动门厂

From electric door electric shock accident, distribution design, electric shock protection

电动伸缩门是一种长期在户外使用的设备，工作电压为220 V（过去也有380 V），其电机是处于移动状态。据悉，在高峰运行期间电动门每小时需开合数十次，这种工作特点势必导致线路极易老化。此外，在雨季电机不锈钢缝隙也容易漏水、积水、造成漏电，发生电击事故。当然这只是电动门发生电击事故的一个原因。应该说这是设备问题、物业管理问题，看起来与配电设计风马牛不相及，其实不然。

The electric telescopic door is a kind of equipment which is used outdoors for a long time. The working voltage is 220 V (in the past 380 V). The motor is in the mobile state. It is reported that during the peak running period, the electric doors need to be opened and closed ten times per hour, which will lead to the aging of the lines. In addition, in the rainy season, the stainless steel crevice of the motor is apt to leak, accumulate water, cause electricity leakage, and cause an electric shock accident. Of course, this is only one reason for the electric shock. It should be said that this is a problem of equipment and property management, which seems to be different from that of distribution design.

为什么要做配电设计？对此答案很多，但是保护人身和设备安全应该是最根本的原因和目的。特别对于电气设备外露导电部分，正常时是不带点的却因绝缘损坏而带故障电压，这时人或动物接触此外露导电部分则会遭到电击，通常将这种电击称为“间接接触电击”。对此，设计人员应尽力做好防护。

Why do you want to do distribution design? There are many answers to this question, but protecting human body and equipment safety should be the most fundamental reason and purpose. Especially for electrical equipment exposed to electrical parts, normal is no point, but the insulation damage and fault voltage, when people or animals contact the exposed conductive part will be electric shock, usually called "indirect contact shock". In this regard, the designers should do their best to protect them.

应提及的是：GB 50054 – 2011《低压配电设计规范》（2012年6月1日起实施）中将电气装置的电击防护分为“直接接触防护”与“间接接触防护”，而在2012年12月1日起实施的GB 16895. 21 – 2011/ IEC 60364 – 4 – 41：2005《低压电气装置  第4 – 41部分：安全防护 电击防护》特别指出：

It should be mentioned that the GB 50054 - 2011 "low voltage distribution design specification" (implemented in June 1, 2012) divides electric shock protection into "direct contact protection" and "indirect contact protection", and the GB 16895.21 – 2011/ IEC 60364 – 4 – 41:2005 "low voltage electrical device" implemented in December 1, 2012. Fourth to 41 part: safety protection against electric shocks "specifically states:

“——正常条件下的电击防护称直接接触防护（本部分改称为基本保护）；

"Under normal conditions, electric shock protection is called direct contact protection (this part is called basic protection").

——故障条件下的电击防护称间接接触防护（本部分改称故障保护）。”

Under the condition of failure, electric shock protection is called indirect contact protection (this part is referred to as fault protection).

在本文中对电击防护的称谓仍是按照 GB 50054 – 2011中的规定实施。

The title of electric shock protection is still implemented in accordance with the provisions of GB 50054 - 2011 in this article.

低压配电系统的接地形式，对间接接触防护的自动切断电源措施极为重要

The grounding form of low voltage distribution system is very important for automatic cut-off power supply of indirect contact protection.

在现行的配电设计中，最常采用的间接接触防护措施是自动切断电源，也就是通常在配电设计中采用各类保护电器对人身、线路及设备进行保护。该保护措施对于不同的低压配电系统的接地形式，其间接接触防护电气的动作特性各不相同。

In the current distribution design, the most commonly used indirect contact protection measures is to automatically cut off the power supply, that is, the protection of the body, line and equipment is usually used in the distribution design. The protection measures are different for different grounding modes of low-voltage distribution system, and their indirect contact protection electrical characteristics are different.

TN 系统中配电线路的间接接触防护电器的动作特性应符合下式要求：

The operation characteristics of indirect contact protective devices in distribution system of TN system should meet the following requirements:

Zs Ia ≤ U0

Zs Ia < U0

式中:Zs —— 接地故障回路的阻抗,Ω;

Type: Zs - the impedance of the grounding fault loop, omega;

Ia —— 保证间接接触保护电器在规定时间内切断故障回路的动作电流，A；

Ia - to ensure that indirect contact protection electrical appliances cut off the fault current in the specified time, A;

U0 —— 相导体对地标称电压，V。

U0 - the nominal voltage of the phase conductor to the earth, V.

由此可看出，TN系统发生接地故障时，电流的切断与接地电阻的阻值无关。

It can be seen that when the grounding fault occurs in the TN system, the cut-off of the current has nothing to do with the resistance of the earth resistance.

对于 TT 系统，其保护电气动作特性应满足下式要求：

For the TT system, its electrical protection characteristics should meet the following requirements:

RA Ia ≤ 50V

RA Ia < 50V

式中：RA —— 外露可导电部分的姐弟电阻和保护导体电阻之和，Ω。

Type RA: the sum of the resistance of the siblings exposed to the conductive parts and the resistance of the conductor to be protected.

在实际设计中最常用的是TN 系统，由于门卫室及电动门是一个很小的用户，往往是不重视其接地故障电流的计算，当然也不会去按上述要求进行接地故障灵敏度校核，这些可能造成电动门发生接地故障时保护电器不动作，给人身带来电击的危险和伤害。

In the actual design, the most commonly used is the TN system. Because the door guard room and the electric door are a very small user, it often does not pay attention to the calculation of the grounding fault current. Of course, it will not check the grounding fault sensitivity according to the above requirements. These may cause the electric door to protect the electrical equipment when the ground fault occurs. The danger and injury of the electric shock.

电动门一般是由门卫室或岗亭的配电箱供电，常选用无选择性的A型开关，通常无法在发生接地故障时自动切断电源，为了使其具有选择性，不妨选具有选择性的B型开关作为电源的保护电器！

The electric door is usually supplied by the door guard room or the distribution box of the sentry box. It often chooses the non selective A switch. It usually can not automatically cut off the power when the ground fault occurs. In order to make it selective, it may choose a selective B switch as the protective appliance of the power supply!

顺便说一下，配电断路器有A、B两类：A型开关只有过载长延时及瞬时脱口二段保护，属非选择性开关；B类则具有过载长延时、短延时及瞬时脱口三段保护，为选择性断路器。如果电源开关选用B类断路器，是可根据接地故障电流的大小来整定脱口电流的数值及动作时间。

By the way, distribution circuit breakers have two types of A and B: A type switches only have over load long delay and instantaneous off two section protection, belong to non selective switch; B class has long time delay of overload, short delay and instantaneous off three section protection, which is a selective circuit breaker. If the B switch is used in the power switch, it is possible to set the value of the current and the action time according to the size of the grounding fault current.

TN 系统在采用自动切断电源措施时，一定要辅以等电位联结

The TN system must be supplemented by equipotential bonding when adopting automatic measures to cut off the power supply.

现今，大部分建筑物的配电设计都采用TN系统。规程、规范都规定：TN 系统在采用自动切断电源措施时，一定要辅以等电位联结。

Nowadays, most buildings are designed with TN system. Regulations and regulations stipulate that TN system must be supplemented by equipotential bonding when adopting automatic measures to cut off power supply.

规范GB 16895.21 – 2011 / IEC 60364 – 4 – 41：2005及GB 50054 – 2011 都规定在低压配电系统中采用自动切断电源的防电击的防护措施，以及该措施失效时附加保护措施。对于 TN 系统而言，等电位联结是十分重要且必须的附加保护之一。

Specifications for GB 16895.21 - 2011 / IEC 60364 – 4 - 41:2005 and GB 50054 - 2011 provide for protection against electric shock automatically cut off power in low voltage distribution systems and additional protection measures when the measure fails. Equipotential bonding is one of the most important and necessary additional protection for TN systems.

为了说明原因，还得从 TN 系统的接线特点说起。

In order to explain the reason, we must start with the wiring characteristics of the TN system.

TN 系统的第一个字母表示电源的一点（通常是中性点N）与大地直接连接，第二个字母则表示电气装置外露可导电部分通过保护线与该接地点相连接，也就是说，TN 系统电源侧的 PE 线是与负荷侧全程贯通的。这样，当电源侧或负荷侧某处发生接地故障，故障电压会通过 PE 线传到其他负荷的外露可导电金属外壳，例如电动伸缩门的金属外壳。TN 系统这种“城门失火，殃及池鱼”的特点，设计者应给予关注。浙江小女孩爬在未运行的电动门上玩耍、深圳一名保安无意触及静止的电动门均遭电击，不幸身亡，经查门卫处的配电箱并未发生过故障，恐怕都与系统内传到的危险故障电压有关啊！

The first letter of the TN system indicates that a point in the power supply (usually the neutral point N) is directly connected to the earth, and the second letters indicate that the electrical device is connected to the location of the electrical device through a protective line, that is to say, the PE line on the power side of the TN system is connected to the full range of the load side. In this way, when a grounding fault occurs somewhere on the power side or on the load side, the fault voltage will pass through the PE line to other load exposed metal shells, such as the metal shell of the electric expansion door. Designers of the TN system should pay attention to the characteristics of "the city gate is on fire and the fish will be affected". Zhejiang little girl climbed on an unoperated electric door to play, a security guard in Shenzhen had no intention of touching the static electric door. Unfortunately, it was killed, and the distribution box in the guard did not fail. I'm afraid all of the dangerous fault voltages are connected to the system.

根据电气设备和电

According to electrical equipment and electricity