Everything you need to know about loop testing

Front matter: We all know a loop testing is a process where the beginning and end are connected. Testing is examining the quality and/or genuineness of anything. Therefore, loop testing, in the simplest of terms, is testing a process from beginning to end which is interconnected. This is a testing technique which is performed to check the validity of loops.

One such test is earth loop impedance test.

Loop Testing

Why you?
If you work with live wiring or electrical devices, you need to understand loop testing. When performing these electrical tasks, you need to keep yourself and others around you safe.

You cannot and should not just blindly start working with electricity without taking into account the welfare of others around you. Prevention is better than cure. Always think of the consequences before you do anything.

Why test the loop?
If there is a fault in the electrical system, the circuit impedance will be as low to allow enough current to flow by. The level of time and impedance will vary between the types of installations, the kind of protection used if there is a miniature circuit breaker involved, what type of fuse is used (rewireable or cartridge).  The fault could be in earth circuit or the line neutral circuit, but you cannot know for sure instantly.

Types of tests
The test meter determines which test needs to be used. If one requires a faster and more accurate test, then a high current test must be performed. But if the test is to be performed on an RCD protected installation than a non-trip test would be taken.

Earth loop impedance test
A fault current is also known as a short circuit. This is when a current is highest in flow under an electrical system. It is measured by impedance and voltage of the electrical supply system. Now the loop testing impedance test is when faults are tested within the existing electric circuit. If the impedance is low between earth and the phase conductor then it is an earth loop fault.

These days our electronic equipment is very sophisticated, hence increasing the need to test each of them often. Earth loop testing impedance test is quick, highly specific and convenient. It focuses on evaluating the ability of an electrical circuit to see if it can even engage in devices like fuses or circuit breakers.

Do not confuse a circuit with a loop. A loop consists of unsuspected elements in which a current flows in parallel paths along the ground. A circuit does not conform to a single design.

A fault in a loop is when a current is traveling from a ground conductor to a service than to a ground connector to a ground grid and in the soil. In the soil, there are parallel paths. In order to make sure these paths function properly the loop testing must have low impedance and allow current to flow through them smoothly and reach the devices. But in the case of high impedance and not smooth flowing current a fault arises. This is detected by the earth loop impedance tester. It is important to test since if the fault is there then the protective devices cannot do anything about it.

As high impedance reduces, the current flow of electricity which is actually required to activate the protective device in the first place. Hence, since the protective device will not work, the circuit will continue to flow current and remain energized resulting in fire, fatal shocks, and other damages.

Accurate Results
A loop impedance tester gives accurate results in just a few seconds, therefore, highly recommended. It assesses all the factors that can contribute to faults in the current and protective devices. Firstly, the tester measures the voltage that is unloaded. Then it checks the resistance between the existing conductors and figuring out any faults.

From the resistor, it measures the voltage drop, if any, in line with the loop testing. The voltage supply’s proportion which shows in the resistor will depend on the impedance in the loop testing. For successful measurement, speed is the main element. The tester operates really quickly. It completes two and a half cycles while measuring the main supply at 60Hz in just 16 milliseconds hence not giving any time for the protective devices to react.

Loop impedance test is reliable and can be completed in just minutes. It is far better than other complex processes which are not even certain- as in they do not provide such accurate results.

Parting ways
There are many service providers which conduct impedance test. When selecting the service provider, do not forget to enquire about any queries you might have regarding their services and how they operate. Ask them to guide you through the whole process before selecting them.


Choose reliability over uncertainty always!


Qais is working as a professional Researcher since 5 years. Currently, He is writing on fitness, Home Decoration, and Tech

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