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The first soil resistance measuring instrument was invented in the 1950s by Evershed & Vignoles Meggers who made the first insulation and earth resistance testers. [2] One of the most used analog grounding testers in USSR were М416. [3] From the 21st century several companies produced digital earth resistance meters and testers.
In such a scenario current will take any alternate path available, and since extraneous-conductive-parts like water and gas pipes should be bonded to an installation's earthing, and the earthing is tied to the neutral, neutral current can still flow via the Earth, potentially passing through neighbouring properties (if their neutral is still ...
A minimum acceptable resistance value is usually specified (typically in the mega ohm (MΩ) range per circuit tested). Multiple circuits having a common return may be tested simultaneously, provided the minimum allowable resistance value is based on the number of circuits in parallel. Five basic isolation test configurations exist: [3]
An insulation resistance test (IR test) measures the electrical resistance of insulation by applying a voltage between two locations, and measuring the resultant current flow. Proper safety precautions must be taken when doing this test, such as exclusion zones, making sure no wires are exposed, and personal protective equipment is worn.
The transmitter power lost in the ground resistance, and so the efficiency of the antenna, depends on the soil conductivity. This varies widely; marshy ground or ponds, particularly salt water, provide the lowest resistance ground, while dry rocky or sandy soil are the highest.
Some utilities install higher-voltage insulators so the line can be easily upgraded to carry more power. For example, 12 kV lines may be insulated to 22 kV, or 19 kV lines to 33 kV. [9] Reinforced concrete poles have been traditionally used in SWER lines because of their low cost, low maintenance, and resistance to water damage, termites and ...
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The ground loop still exists, but the two sides of the loop are close together, so stray magnetic fields induce equal currents in both sides, which cancel out. Break in the shield Create a break in the signal cable shield conductor. [5] The break should be at the load end. This is often called ground lifting. It is the simplest solution; it ...