Grounding / Earthing. What Does These Lines Mean?

For one thing, the specification must be inaccurate; there is no such thing as 0Ω.

Follow the electrical codes applicable to the country of installation. In the UK, for example, this would be BS7671.

I would say that your manual was translated from another language (Chinese?) to your native language or to English.

"There must be a good third wire ground, preferably to a true ground or ground rod. Then check the resistance to that ground to all the contact surfaces of the equipment. There should be 0 ohms resistance since the static generated by the motion of the product needs a place to go".

I would translate this as telling you to ensure the frame is bonded to your safety ground (third wire ground). The "contact surfaces" infers without telling you specifically that you must ensure that all paint and coatings have been removed from the grounding point on your equipment for the bonding location.

Zero ohms is a bit extreme. Normally 1, 3 or 5 is specified and attainable. "...static generated by the motion of the product needs a place to go" That is a loaded statement. I guess that is one way to look at it. Ground is not a sink with a drain that magically dissipates spare electrons. It is the return path for an electric system/circuit. However, putting the frame of the equipment at the same potential as the operator who may have purposeful or incidental contact with the equipment is the intent here.

As others here have stated, you need to refer to your local Authority Having Jurisdiction (the electric guys in charge where you live) and find out what they want/need you to do.

Understanding and doing is one thing...doing it the way other people understand it can be totally different.

The manufacturer want two independent earthing for their machine

1. For the static discharge which they want value of 0 ohms

2. Regular earthing for the protection of machine and operator as per safety rules.

In the present case since there is only line and neutral available from the wiring for your location it is essential to provide another independent earthing for protection

Both these earthing has to be provided as per standards of electrical safety regulations of your location.

The earth resistance to be measured with the help of earth megger.

testing method as given in he following link.

http://www.biddlemegger.com/biddle-ug/DET54R54D_UG.pdf

Using two separate earthing locations can be dangerous (since you are grounding the case of machinery) and is normally not allowed under code. The two grounds, of course can (and should) be connected. That would only serve to further decrease your resistance to earth anyway (not by much under most circumstance, but every little bit helps).

I don't see the logic to using an entirely separate earthing location just for static discharge. You have to ground the case to safety anyway (the bond).

I have used ground fields for antennas and other equipment, but that was specifically designed as an RF ground, quite different.

I still say "0" ohms is impossible. Everything has resistance.

You said, it is correct, to get earth value of 0 ohms earth resistance is practically impossible .

The subject of earthing is a very complex procedure and we in India have to strictly follow the Indian Standard code of practice for earthing for all the electrical works .

IS 3043I 1987 .This code is made taking in to account most of the international standards.

The earthing method I recommended is as per that.

http://xa.yimg.com/kq/groups/4164488/669480774/name/IS+3043+Earthing(1).pdf

Thanks for that. I have some of the Canadian electrical code (akin to the U.S.'s NEC) and some Australian codes, but have not seen the Indian codes and such. It surprises me to see that it was in English even in 1987.

Is that the latest revision...1987 copyright 1988? That would be even more surprising to me. I will print this and put it in my "library" if this is the latest version. I love reading this stuff and making correlations to the IEEE and NEC publications.

You are welcome.For your information India was a British Colony till 1947 (Indian Independence ) There after it became Republic of India . All the official transactions were carried out in English even after India became a Republic and in most of the Indian Universities the medium of instructions were and are still in English. Hindi was chosen as official language .But different Indian States had their own language which was spoken and written.But English remained the common link language and is used for all official purposes and remained second official language. Majority of the educated people read ,write and use English for most of the purposes. Even though Hindi versions are also available for all official purposes most of the people use the English version. Even now most of the Engineering Science and Medical books are available in English only.