Insulation fault locators are used in combination with insulation monitoring devices for localisation of insulation faults in unearthed power supplies (IT systems). They detect the test current signals generated by the insulation monitoring device using measuring current transformers and evaluate them correspondingly.

Insulation fault locators allow locating the fault source within a short period of time and during ongoing operation.

Insulation monitoring devices continuously monitor the insulation resistance of IT systems (unearthed systems) and issue an alarm if the value falls below a response value.

To obtain a measurement, the device has to be connected between the IT system and the protective earth conductor (PE). A measuring current is superimposed onto the system which is detected and evaluated by a measuring circuit. Insulation monitoring devices detect deteriorations of the insulation level at an early stage and in a reliable way.

Residual current monitors are used to monitor earthed systems (TN and TT systems) for fault currents or residual currents. The sum of all conductors except the protective earth conductor is measured by means of measuring current transformers.

In general, residual current monitors (abbreviation RCM) are used to send a message to the user even before reaching the shutdown threshold of the RCD. Residual current monitors detect deteriorations of the insulation level at an early stage and in a reliable way.

The idea of a neutral grounding resistor is to limit the maximum fault current in order to avoid damages and hazards caused by ground faults. Since the system is technically grounded (e.g. High Resistance Grounding) protective relays will work properly.

Early detection of a change in the NGR value provides the ability to plan repair and indicates previously unknown hazards.

Neutral Grounding Resistor Monitors measure voltage, current, continuity of the NGR connection and phase-to-ground voltage. This information helps to plan maintenance and enhance system availability.

Universal measuring devices (also power analysers) record all relevant electrical quantities of electricity networks. The scope of measurements ranges from currents and voltages through energy consumption and performance to displaying individual harmonic components of current and voltage for assessment of the voltage quality.

Measuring devices for Power Quality and Energy Measurement (PEM) provide transparency for electrical installations. Adjustable threshold values allow notification via relay outputs. All recorded data can be conveniently called up via bus systems or browser access.

Various measuring and monitoring relays are available for the purpose of monitoring electrical quantities. In addition to overvoltage, undervoltage, frequency, unbalance, phase sequence, phase failure and loop monitoring, special solutions for specific applications are also possible: extended temperature ranges, sector-specific standards, compact design, country-specific profiles.