3 Point Grounding Testing

Most people recognise the need for grounding of electrical systems for personnel protection, but the grounding system also serves as the basis of the electrical protection of your site or facility.  It determines the effectiveness of the lightening protection and surge protection systems.  Without good grounding, these systems do not function.  Grounding also serves as the path for system noise to be dissipated from equipment.

As time goes by, grounding systems need to be tested for effectiveness because of bonding breakdown, corrosion, oxidation, degeneration of material and soil properties change.  The Fall of Potential method is the most recognised method for measuring the resistance to earth of a grounding system, or the ground system performance. This testing methodology is based upon the IEEE standard, and when properly performed, is a very accurate test.  Clamp on meter tests are not accurate and can give a false impression of the state of the grounding, due to stray currents flowing through the systems.

For a 3 point test to be valid, the grounding system must be electrically isolated. If, not the readings will reflect all the grounding systems in the area connected in parallel.  Protecting your systems from lightening, stray electrical energy, or bandwidth noise, requires a properly designed and maintained grounding system.  In today’s environment where Fibre Optic Cables are brought into the premises, it is often though that there are no electrical dangers present since the Fibre Optic cables do not conduct electricity.  While this is true, the strain relief metallic cable strung with the Fibre Optic Cable can conduct sub surface electrical energy and bring it into your premises. AMBA Energy Limited offers site grounding audits with a full written report.