# How can you measure Earth Fault in an Electrical Circuit ?

Suppose there is a fault then how will you ensure that there is an earth fault or not.

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• Anonymous

I am having trouble understanding your question, there are two possible answers.

If there is a fault with the Earth then it can be measured using resitometer to meaure the resistance between ground and the earth cable (this should normally be zero)

If you are trying to meaure how much current is being lost to earth then connect an ammeter series with the earth to meaure the current flowing to earth.

Refer to the Institute of Electrical Engineers Onsite Guide for circuit tesing standards if working in the UK.

• 3 years ago

potential short circuit modern (%.). it rather is the present you may desire to get in case you have a quick circuit on your furnish. The electrical energy furnish agencies positioned up figures for this (%.), many times at your electrical energy meter it rather is approximately 13000A (13KA). As you install a equipment from onwards from the meter the %. reduces (the cables resistance reasons this to drop, no longer large in a house yet in a production facility the drop would nicely be extremely large). the fast circuit modern is what blows a fuse or journeys a circuit breaker. each of those desire a definite modern until now they injury the circuit and if the %. is smaller than this then the keeping gadget won't artwork. The %. is measured on the furthest element interior the circuit - the worst case the place the fast circuit modern is least. Earth Electrode Resistance. The earth Electrode is the element the place the earth is hooked as much as earth (large planet concern). Measuring this shows how nicely the equipment is conecte to earth. If the resistance is purely too intense then there is an hazard that a fault will discover an much less stressful course for the electrical powered energy to holiday to earth - this would be a individual which isn't god. Measuring the earth electrode resistance shows how stable the earth is and whether it rather is going to artwork

Unfortunately, there is no practical method of measuring earth faults as the impedance at the point when the earth fault occurs can vary enormously. ie. take the case where a power line falls to ground. It may fall in an area where the soil restistivity is high or low, it could be wet or dry etc. etc etc.

Current flowing to ground (or earth depending in what part of the world you live) depends on the "Fault Level". Fault level is the maximum available fault current that can flow into a bolted short. (either to ground or between phases). The fault level is determined by the Z% of the transformer feeding the fault however, the level of available fault current at the fault's location is mitigated by the circuit impedance up to the location.

To summarize...... Current flow into an earth fault has to be calculated rather than measured as the earth fault currents can be as high as 100,000 amperes.

Source: Electrical Engineer with 40 years experience

Measure current in on the live and out on the neutral - they should be the same. If not, the difference is flowing to earth, probably through a fault (for example through the body of the user of an electrical piece of equipment). This is what earth leakage protectors do ie. if there is a difference (above a predetermined safe limit) the protector shuts down the circuit to prevent damage or injury.