The Dold RN5897.12/010/61 AC/DC85-230V is a high-quality insulation monitor, specifically designed for preventive fire and system protection in industrial applications. It detects both symmetrical and asymmetrical insulation faults and enables rapid fault localization through selective earth fault detection on conductors L+ and L–. This significantly improves the efficiency and safety of maintenance and servicing of electrical systems. The device is universally applicable in ungrounded AC, DC, and AC/DC networks with a nominal voltage up to 300 V, and is particularly suitable for systems with high network capacitances up to 1000 μF. The optimized response time under such capacitances ensures reliable monitoring even under challenging conditions. Even in the event of a de-energized network, monitoring remains active, ensuring continuous safety. Additionally, the insulation monitor checks the measurement circuit L(+) / L(–) and the protective earth connections PE1 / PE2 for wire breaks, ensuring complete system integrity. Setting the trigger values and parameters is simple via a rotary switch and an intuitive menu navigation, greatly simplifying commissioning and configuration.