In a tt system where a connection to earth is not provided by the.
Earth mat testing procedure.
Several tests are conducted to check the safety of products.
Various governments and agencies have developed stringent requirements for electrical products that are sold world wide.
Frank wenner of the u s.
The value is the resistance of that particular leg of the mgb.
The measuring procedure described here uses the wenner method and uses the formula.
Earthing mat is made by joining the number of rods through copper conductors.
Mat ansi astm d178 or equal while operating the test set.
Thirdly measure the individual resistances of the ground system using the selective test of the earth ground tester see fig.
This method is derived from the 4 point method which is used for soil resistivity measurements.
The substation earthing system comprises of a grid earth mat formed by a horizontal buried conductors.
The grounding system in substation is very important.
Concrete or coke in electrical contact with the earth.
Earth electrode conductive part which may be embedded in the soil or in a specific conductive medium e g.
Read about design of substation earthing system here.
This is unlike a small single electrode for example a lightning.
Bureau of standards now nist developed.
An earth electrode and earth electrode resistance are defined in bs 7671 as.
In order to obtain a low enough value of earth resistance earth systems may consist of an earth mat covering a large area or many interconnected rods.
Electrical safety testing is essential to ensure safe operating standards for any product that uses electricity.
It reduced the overall grounding resistance.
The 3 point method called the fall of potential method comprises the earth electrode to be measured and two other electrically independent test electrodes usually labelled p potential and c current these test electrodes can be of lesser quality higher earth resistance but must.
One among that is earth test.
Testing large earth systems.
Earthing mat is mostly used in a placed where the large fault current is to be experienced.
Measure the resistance of the mgn.
Such type of system helps in limiting the ground potential.
2 oct 2005 5 of 11 testing procedure before installation of gratings lv rubber gloves must be worn at all times when test leads are connected to the substation earths.
While designing an earth mat the following step is taken.
