Need Earth resistance value for emission measurement

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elexlearner

Joined: 27 Jun 2008
Posts: 31
Location: India

02 Jul 2009 11:39 Earth resistance

hi All,

I wanted to know that what should be the value of Earth's resistance for a correct conducted emission measurement results.

Any document which can help in understanding the subject...

jimjim2k

Joined: 17 May 2001
Posts: 1248
Helped: 11

02 Jul 2009 18:23 Earth resistance

Hi

Look:

1. h**p://www.duncaninstr.com/Gr_article.htm
2. h**p://www.polyqual.com/pages/relTopics/earthing/measureResis.html

* -> t

tnx

flatulent

Joined: 19 Jul 2002
Posts: 4868
Helped: 324
Location: Middle Earth

03 Jul 2009 2:01 Re: Earth resistance

There have been many books and article over the past several decades on earth resistance. One example is government laws which are codified in building codes for safety with the AC mains. You have to be careful with these mains. Many laws state that there should be just one earth connection. I know of one "best practice" electrical engineering recommendation that a bare wire is made into a loop that goes around the circumference of a building and is bare and buried into the earth (bare soil) and all grounds connected to it. You should examine the laws in your country and city for details.

dipnirvana

Joined: 23 Jan 2009
Posts: 207
Helped: 21
Location: India

03 Jul 2009 4:16 Re: Earth resistance

Hello elex what do u mean by "correct conducted emission" ...what problem do u facing ?

what is your exact problem.

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elexlearner

Joined: 27 Jun 2008
Posts: 31
Location: India

03 Jul 2009 11:53 Re: Earth resistance

actually i am facing a problem of high ambient in the CE test setup i am making.
The setup using ESPC (EMI receiver) and ENV4200 (3-phase LISN) both are connected to the earth (dedicated pit for this setup). I thought it to be because of poor earthing as I am getting its resistance around 3Ω at the plane (setup is installed on this)

I am attaching the sweep of ambient noise and EUT's emission which shows no significant difference. In my perception either

1. Earth connection is not proper
2. LISN is broken
3. I have made some wrong earth connections. ( between LISN, reciever and PC)

or may be some other reason which I don't know....

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