Testing TN-S systems without interruptions

Testing and measuring the insulation resistance. Shutdown for testing?

In order to carry out normal insulation tests, electrical installations and equipment to be tested have to be switched off – a time-consuming and costly task, which is virtually impossible in installations where high availability is required.The German Social Accident Insurance DGUV regulation 3 and the DIN VDE 0100-600: 2017-06 standard allow the use of a permanently installed residual current monitoring system (RCMS) as an alternative to shutting down an installation. In this case, suitable proof has to be provided which is possible by means of an RCMS memory file.This means that the test protocol on the insulation resistance required by the DGUV Vorschrift 3 (German Social Accident Insurance) is automatically generated.

The use of a permanently installed RCMS offers plant operators a safe solution for measuring without shutdown.

[Translate to english:] DGUV Anwendungsbeispiel

Visualisation of faults

In the case of selective installation of residual current transformers all existing insulation faults can be simply displayed and evaluated on the local display but also via a gateway or at the control centre.

An easy comparison of costs

How much are the annual costs for plant shutdowns and manual measurements by service staff? The installation of 12-channel RCMS systems are generally much less expensive and pays off more from year to year. Already the annual costs for measurements by service staff generally cover the cost of materials of an RCM.

Continuous monitoring – Protection for people and equipment

According to the German Social Accident Insurance and the German Technical Inspection Authority, the requirements for continuous monitoring of stationary systems and electrical equipment are met when metrological measures are applied for measuring the insulation resistance and the residual current. Any existing insulation problem is reported immediately and automatically forwarded to a central location and is then inspected and remedied, if necessary, by an electrically skilled person.

If these conditions are met, the inspection intervals for insulation measurement can be adapted to practical application during the next periodic test in energy distribution systems and industrial plants.

Cost certainty

  • Continuous monitoring saves time and money
  • Measuring without switch-off, operation continues to run
  • Maintenance measures can be planned
  • Central access via web browser saves time and effort

Legal certainty

  • Continuous overview of the system, continuous measuring and monitoring of all electrical equipment connected
  • Automatic alarm message at a central point
  • Documentation and records via history memory and data logger

Fail safety

  • Continuous measuring instead of one measured value per test
  • Remote diagnostics possible via Internet/Ethernet
  • Fast visualisation of measurement data
  • Early detection of insulation deteriorations
  • Fault detection during installations and maintenance
  • • Reduced fire risk

Analysing and Reporting:


Flyer DGUV Vorschrift 3 (269 KB)
Produktübersicht Differenzstrom-Überwachung (7,1 MB)
Fachbeitrag "Ständiges Überwachen"
Fachbeitrag "Wiederkehrende Prüfung ohne Abschalten"