Earth Resistance / Impedance Measurements

It is vital that an effective earthing system is installed and maintained correctly, as this is paramount for the safety of personnel and equipment at electrical installations.

In order to verify the adequacy of a new or existing earthing system, a measurement of the earth resistance / impedance of the earthing system is crucial. This is fundamental in determining the ability of the earthing system to:

• Safely carry hazardous faults current back to source.
• Control Earth Potential Rise (EPR)
• Limit touch, step and transferred potentials.
• Prevent hazardous potential differences between conductors or other equipment.

ERM’s highly qualified team use experience, knowledge and expertise in order to test and analyse a diverse range of earthing systems from small installations to extensive interconnected systems, using the fall-of-potential in accordance with BS EN 50522 as well as other alternative methods, dependent on the application.

ERM has the capability to measure earth impedance using bespoke in-house developed current injection equipment. This is important for larger area sites as commercially available testers test at DC and will underestimate the earth impedance and therefore the EPR, touch and step potentials and third party interference voltages.

ERM has a strict environmental policy with regard to field testing. All land access is pedestrian only so that land is left in the way it is found.