Clamp meter for measuring grounding resistance directly on grounding rods (NO SHUTDOWN METHOD) and compatible with multifunctional measuring instruments T2100 is a professional clamp meter specially designed for assessing the resistance of grounding rods without disconnecting any part of the system, in conjunction with multifunctional measuring devices. The device's internal part consists of 2 probes, one for reading current and the other for generating voltage. The voltage clamp generates a potential (E) on the loop during resistance (R) measurement. Accordingly, a current (I) is generated on the loop, which is measured by the current probes. Based on the parameters E and I, the device displays the resistance value R, calculated as their ratio. The measured value can be used if individual rods do not influence each other. T2100 can be used in conjunction with testing devices MACROTESTG3, MACROEVTEST, and GSC60, connected via the built-in RS-232 port, for uploading saved test data. This device complies with IEC/EN61010-1 standard in CAT III 600V, CAT IV 300V categories and is an ideal solution for measurements conducted in both private and industrial environments.