Clean earth grounding or low noise earth shall be provided as required, to ensure that the level of induced or conducted interference from external sources, including the facility power grounding system, does not produce incidence of malfunction of the equipment, which is unacceptable for the operating system. The electronics systems must be protected by providing a network path having low impedance for interconnecting its equipments.
Proper routing, zoning and shielding of the cables / earth wires are important and must serve the purpose of preventing sources of electrical disturbances from the operation of electrical equipments.
What is Clean Earthing or Grounding?
In a networked environment, electronic / instrumentation equipments and instruments to be externally connected through earth wire to an earthing system that should not have any potential difference between any network point to the earth under normal working condition known as Clean Earthing or Clean Grounding. It should be a dedicated earthing system that related to sensitive electronic and/or instrument and in no way it should be in contacted with main power throughout entire networking.
How to Make Clean Earthing or Grounding Termination Pit?
To make a good low impedance earthing pit that acts a a bonding to ground, you need to have high conductivity, corrosion resistant conductor either copper earth rod or mesh buried in the earth as per the standards. When you chose the location of the pit, care should be taken so that the pit and its surrounding should be frozen or completely dried out. It has to be kept away from other earthing pits such as electrical power earthing and lightning protection earthing.
Other Important Points to Clean Earthing or Grounding System
- Clean earth grounding system shall not be connected to any other earthing or grounding system.
- Clean earth grounding cables shall not be run parallel with other grounding cables or power cables.
- Clean earth grounding system shall comply with IEC 60950 and BS EN 50310.
- Clean earth grounding pits shall be separated from other earthing pits by a distance of at least 1800 mm.
- In general clean earth grounding shall be provided for data system, telephony and other communication systems, and UPS.
- Clean earth grounds shall have an earth impedance of less than 1 ohm.