the metrological laboratory
Our technicians recieved an interesting question about specialized grounding - "What is a metrological grounding and how to organize it?". We answer to this question!
Metrological grounding means grounding, which is necessary for the proper functioning of the measuring equipment in metrological laboratory.
Excerpt from GOST R 50571.21-2000:
3.15 functional grounding: Grounding, to ensure the normal functioning of the device, on the case of which, there should be a minor electric potential upon the request of the developer (sometimes this requires presence of a separate electrically independent ground electrode).
As for the second part of the question - about the way to organize such grounding, there is a need to follow the standard requirements. Functional (metrology) grounding is performed, usually combined with protective and should have resistance not more than the indicated in the pasport or manual to the measuring instrument (can be 4, 2, 1, 0.5 Ohm). Also along the perimeter of the room at the height of 0.6 meters a potential equalization bus made of 8 mm copper is being laid, to which, all the equipment is connected by functional ground electrodes (FE- conductors) with the cross- section 25 sq mm.