How to calculate the groundness

[pixel01]

Dear all,

I am going to install an instrument. As usual, it needs ground wire and I have it installed.
However in the specs they require that the groundness is <0.5V/ms. I really do not understand that unit and how do they measure the goundness.

Thanks for any ideas.

Regards

 

[berkeman]

Dear all,

I am going to install an instrument. As usual, it needs ground wire and I have it installed.
However in the specs they require that the groundness is <0.5V/ms. I really do not understand that unit and how do they measure the goundness.

Thanks for any ideas.

Regards

Yeah, that's a new word for me as well. Maybe related to some GFCI spec, since there's a time component to the spec. Can you post a link to the product and datasheet?

 

[pixel01]

Yeah, that's a new word for me as well. Maybe related to some GFCI spec, since there's a time component to the spec. Can you post a link to the product and datasheet?

Sorry for the late reply. Our lab is going to install an ICP instrument and the customer engineer asks us to prepare some conditions for the installation. About the electricity he wrote: "All the powerlines must have groundness (Ground to Neutral <0.5V ms)"

 

[berkeman]

Sounds like it's just a language translation thing. Thanks for the clarification, pixel.

 

[dlgoff]

Don't you mean <0.5 volt rms? Root Mean Square voltage value of AC on the neutral?

 

[pixel01]

Don't you mean <0.5 volt rms? Root Mean Square voltage value of AC on the neutral?

Oh, thank you. That's correct, the fax is dim and the 'r' is almost gone.
Anyway, how can I check the 'gound to neutral' smaller than 0.5V ?

 

[dlgoff]

Oh, thank you. That's correct, the fax is dim and the 'r' is almost gone.
Anyway, how can I check the 'gound to neutral' smaller than 0.5V ?

Just set your volt meter to measure ac rms volts and connect it between ground and neutral wire at the distribution panel.
You might want to get electrician to do the measurement if you are uncomfortable with the getting into the panels however. Safety first.

Edit: On second thought, maybe the measurement should be made at the instrument location. Maybe someone else here knows where the appropriate place to make it.