Easy way to measure earthing and soil with SONEL MRU-11 meter
Simple is better! When performing earth resistance measurements technical method is usually sufficient. It’s easy, provides us with precise reading and there is no need to invest in a sophisticated, expensive meter. Ordinary, inexpensive, single method earth resistance meter is suitable for most of the jobs. What if measurement conditions get a little complicated? The result of earth resistance measurement is the summary of resistance of the earthing (part of electrical system) and resistivity of the earth (soil). The earthing, regardless of its type, usually has relatively small resistance, as it is made of a conductive metal. The significant component is the resistance of the soil, which depends on the type of land (clay, sand, rocks, etc.). In order to examine the ground, soil resistivity measurement is necessary. Knowing its value enables determine the depth at which the ground has the lowest resistivity. This information cannot be overestimated by designers and contractors of earthing systems, since it allows for a considerable reduction in both the costs of material used for the task and the working time needed to make the earthing system. In many cases, the resistivity measurement is necessary in order to specify the required resistance value for the tested earthing system.
Unfortunately, many simple earth resistance meters don’t allow for soil resistivity measurement. Does it mean that investment in an expensive, complex earth resistance meter with multiple measuring functions is unavoidable? Not necessarily. SONEL S.A. prepared a perfect solution for such situations – earth resistance meter MRU-11. This meter allows for both earth resistance and soil resistivity measurements.
Measuring functions
Measurement capabilities of SONEL MRU-11 completely cover the needs of typical measuring situations. The meter provides:
- soil resistivity measurement with Wenner method with automatic result recalculation in Ωm and Ωft;
- earth resistance measurement using 3- and 4-wire method with auxiliary electrodes;
- earth resistance measurement using 2-wire method.
The meter is also provided with the following, very useful functions:
- resistance measurement of auxiliary electrodes RH and RS;
- measurement of interference voltage to 100 V;
- measurement in the presence of noise voltages in the networks with a frequency of 50 Hz or 60 Hz;
- selection of maximum measuring voltage (25 V and 50 V);
- battery level indication;
- Auto-OFF function.
Rugged casing
With IP67 casing this new instrument is resistant to dust and water, which is undoubtedly a useful feature, if works are carried out exclusively outdoors. Small size (221 x 102 x 62 mm) and light weight (660 g) makes it easy to carry, rubber cover ensures firm grip and relatively large, backlight display (3.5”) provides clear and convenient readings. All measuring functions are accessible directly from the keyboard. With measurement category CAT III the meter can be used to test fixed installations in buildings. All these features makes SONEL MRU-11 very ergonomic and easy to use.
Accessories
The standard package has all accessories necessary to perform available measurements. In soft carrying case there are four probes/electrodes (25 cm) for driving into the ground, two 15 m-long test leads, a 30 m-long test lead, two 2.2 m test leads, two crocodile clips, set of batteries and hanging straps.
Calibration certificate issued by ISO 17025 accredited laboratory is supplied with the meter by default.
Optionally, the user can get long earth probes (30 cm or 80 cm), variety of test leads, up to 200 m long and a cramp used to connect the meter to the earthing system. This cramp ensures good contact with the earthing. It is even possible when the earthing which we wish to connect to is corroded or covered with paint. The meter can be powered by both disposable or rechargeable batteries.
All these features make SONEL MRU-11 a minimum requirement for earth resistance measurements. It’s reliable, rugged and ergonomic – simply better.
