HuaTianLogo

Power detection technology / Power detection

Detection Technology

Loop impedance test

time:2020/6/4   source:华天电力  reading:333 time

Each circuit must be tested to ensure that the actual loop impedance does not exceed the specified impedance of the relevant protection device. Due to the severity of contact electrical faults, impedance testing of grounding fault circuits for electrical equipment and power supply points is very important. Your system is valuable and needs to be maintained to ensure the persistence and functionality of your business. In most homes, basic shock protection is achieved by placing a ground circuit with an automatic switch in the indoor wiring circuit. This will quickly cut off the power supply to the ground circuit in the event of a failure and the touch voltage exceeds an acceptable limit.


In accordance with current national safety standards, you are required to conduct loop impedance tests at your premises to ensure the safety of all guests and employees. Grounding of all electrical installations and power points must be tested to detect any faults within the circuit. A properly functioning ground circuit will allow the detection of circuit faults and facilitate MCB (miniature circuit breaker) responses. The technician will detect the resistance level in the ground loop and notify you if the resistance level is wrong that the resistance must be low enough for the circuit breaker to work properly. Will inspect and test your wiring and require us to carry out tests to protect your staff and your responsibilities.


Earth Resistance Tester.png


The required impedance and time value will vary depending on the type of installation (TN/TT, etc.) and the type of protection, for example, whether it is a miniature circuit breaker (MCB), a plug-in fuse or a reconnect fuse, the fault current can be in a neutral or ground circuit, and therefore the loop impedance of each circuit needs to be confirmed.


It is generally considered that the resistance can be expected to be low enough under ground fault conditions to reach the specified correlation limit in cases where the measured impedance of the circuit's ground fault loop is not greater than 80% of the specified correlation limit. And comply with the regulations, and the protection device automatically disconnected within the specified time.


Appropriate protection against electrical shock hazard can be provided when the TT wiring system meets the following requirements:


Ra X Ia < 50,


"Ra" is the sum of the resistance of the ground rod and the protective conductor, and "Ia" is the maximum current of the protective system. The value of Ra multiplied by Ia should not be greater than 50V, that is, in case of ground fault, the maximum voltage that a person can touch will not exceed 50V.


A fault loop impedance test is performed between the conductor and the ground. To test the loop impedance, our technicians will use a grounded loop impedance tester, which is plugged into a power outlet (GPO) for reading.


Copyright description: all articles, pictures, video and other materials on this site belong to wuhan huatian power automation co., LTD. For use, please contact us; Permission to reprint articles, pictures, video and other materials please quote "from: huatian power".

How to use the circuit breaker tester  | 2020/6/5 | reading318time Megohmmeter accuracy  | 2020/6/4 | reading327time return