关于绞线盘的接地电阻(关键词:电源线接地电阻)

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EN 61242中关于线盘的接地电阻的测量中,有如下规定:
9.7 Internal earthing circuit in cable reels, including any joints contacts and the like, shall be of low
electrical resistance.
Compliance is checked by the following measurement which is made after the test specified in Clause 21.
A current derived from an a.c. source, having a no load voltage not exceeding 12 V, and equal 1.5 times rated
current of the cable or 25 A, whichever is the greater, is passed through the earthing circuit.
The voltage drop is measured and the resistance calculated from the current and this voltage drop.
The resistance shall not exceed 0,05 Ω..

测量时,发现如果包含其线盘所带的电缆在内测接地电阻,是绝对大于0.05的,而且主要的电阻产生于电缆本身,
我知道在60335中测接地电阻时将电源线是排除在外了的,但是在这个标准里面并没有提到这一点,但是考虑到一般电缆在一定长度下也达不到0.05的限值,那是否意味着这时也应将电源线排除在外呢?但有个问题就是,如果将电源线排除,那么绞线盘的接地电阻还有什么意义呢?

希望大家能讨论一下,指点迷津..谢谢~!!