The electrical clean earth also known as low noise earth is a low impedance earth point. It has negligible or zero conducted noise, either already existing or as a possibility, when bonded to a circuit.
The clean earth grounding ensures that the level of conducted or induced interference from outside sources, including the power grounding system in the locality, doesn't cause malfunctioning of equipment essential to an operating system.
Since the earth is multiple-bonded and is common to all systems that connect to the supply, there is a possibility for it to get contaminated with varied signals. Some equipment is particularly bad at generating common mode noise that affects other sensitive equipment. An effective way of reducing the issue is by efficient isolation of the source or the sensitive unit. Using the isolation technique along with the clean earth grounding provides a complete solution.
Ensure that the clean earth grounding system does not connect to any other grounding system. The clean earth grounding cables should not run parallel to any other power or grounding cables. In addition, the clean earth ground needs to have an impedance of less than one ohm and should be at a minimum distance of 1800 millimetres from other earthing pits.
Structural steel, metallic water pipes and specially positioned earth rods are local earthing points that can be suitable for a clean earth.