Created by M.L., OST, on 19.03.2025
- Description: Measurement of the electrical resistance between the connectors and the earth (leakage current), as well as the continuity of the protective conductors.
- Equipment: Dedicated hardware, mostly included in IV-curve tracers. Most inverters monitor the leakage currents too.
- Requirements: Access to the electrical connectors of the individual strings. Wet weather represents the worst-case conditions for the leakage current test, whereas dry weather is the worst-case condition for the continuity of the protective conductors.
- Gained insights: Electrical safety of the installation.
- Recommended frequency: These measurements are part of the mandatory regular inspections, which have to be performed every 3-20 years, depending on the type of installation (see Appendix of the NIV [1]). In case that the inverter gives an alarm regarding leakage current, these measurements are the key element to localize the issue.
- Advantages: Little equipment needed.
- Disadvantages: Results might depend on weather conditions (dry/wet).
- Effort:
- Global: low-medium.
- Costs: low.
- Time: low-medium, depending on required frequency (on-site measurements).
- Providers (non-exhaustive list):
- Included in IV-curve tracer: Benning, Fluke.
- Separate instrument: HT instruments, Benning, Fluke.
- Links:
- Details of the measurements to be performed for the mandatory inspection: SN EN 62446-1 [2]
- Additional notes: If IV-curves are being measured on site, these isolation measurements can be included with little additional effort.
References
- Schweizer Eidgenossenschaft. SR 734.27 – Verordnung über elektrische Niederspannungsinstallationen. Fedlex 2001. https://www.fedlex.admin.ch/eli/cc/2002/22/de (accessed December 4, 2024).
- Electrosuisse. Photovoltaik(PV)-Systeme – Anforderungen an Prüfung, Dokumentation und Instandhaltung Teil 1: Netzgekoppelte Systeme Dokumentation, Inbetriebnahmeprüfung und Prüfanforderungen 2016.
