The concept of protecting people or electrical equipment in mining operations when ground faults appear is especially critical because these are very common: the very nature of the operations greatly degrades the electrical insulation of conductors or loads, for example, Motors, luminaires, cables, frequency converters are key elements for production, and are continually affected by elements such as humidity, dust, mechanical traction, temperature, harmonics or voltage variations. This compromises the very continuity of operations, and what is much more important, security.
 
To guarantee the safety of personnel or electrical equipment, what we know as devices capable of detecting residual current, commonly known as differential relays, are used. These devices are reactive, that is, when they reach a preset threshold they cause a trip, and therefore disconnect the electrical installation, interrupting operations of course. 
 
But it is not always necessary to interrupt the power supply, in the case of Bender the solution is Residual Current Monitors or RCM and Modular Residual Current Devices or MRCD. The first device or RCM according to IEC62020 and consists of a pre-alarm or warning threshold, and a main alarm or disconnection, and between both (pre-alarm and alarm) there is always a wide time window, which can be of days or weeks; This time window is used to locate the ground fault while the electrical system is energized, and it is only necessary to interrupt operations at the time we want to remove said fault.