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Anonymous Poster #1

Instrument Ground Cable

04/14/2015 12:04 AM

Gents,

Good morning,

In our plant the protective earth cable is directly connected to the instrument shield bus. there is no any instrument earth cable is connected. So please clarify the consequences. For me this is wrong connection and there is chance to getting errors on the instrument signals (especialy Bently nevada system). what is your thinkings?
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lyn
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#1

Re: instrument ground cable

04/14/2015 12:21 AM

I'm thinking the manual would tell you how to install the instrument.

Or, experience would allow you to know.

If none of the above are true, call Bently Nevada.

Or, just call the Anonymous Poster's Anonymous help line.

1-800-3862-277.

Write if you get work.
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Crabtree
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#2

Re: instrument ground cable

04/14/2015 2:32 AM

I'm thinking you need to have a qualified Electrical Engineer review your installation and report with recommendations. I'm thinking you have a snowball's chance in hell of getting anything sensible out of a bunch of anonymous strangers over the internet. Then, I'm funny that way.

Oh, and don't call me gent.

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adreasler
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#5
In reply to #2

Re: instrument ground cable

04/15/2015 9:50 AM

Then I guess I'm funny too, because I agree with you 100% on that.

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StandardsGuy
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#7
In reply to #2

Re: instrument ground cable

05/11/2015 9:57 AM

OK, Mildred, we won't call you gent.

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Brave Sir Robin
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#3

Re: Instrument Ground Cable

04/14/2015 10:52 PM

If you don't connect the instrument shield bus to protective earth, what would you connect it to?
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Wal
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#4

Re: Instrument Ground Cable

04/15/2015 12:02 AM

It depends on where the 2 earth systems are connected.

They will be bonded somewhere.

If say they are connected together at a motor casing cover screw then probably wrong.

If they are connected at a purpose designed and properly implemented bonding point then probably OK.

Show it to us.

Show yourself!!!!

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StandardsGuy
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#6

Re: Instrument Ground Cable

04/15/2015 9:54 AM

I don't believe that your entire plant has no earth connection. If true you are vulnerable to lightning strikes that could wipe out everything including the people. Instrument shields should connect to common, which is usually the chassis or metal box surrounding a circuit. What is the Bently Nevada system?

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adreasler (1); Brave Sir Robin (1); Crabtree (1); lyn (1); StandardsGuy (2); Wal (1)

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