IEC 61557-9:2009 specifies the requirements for insulation fault location systems which localize insulation faults in any part of the system in unearthed IT a.c. systems and unearthed IT a.c. systems with galvanically connected d.c. circuits having nominal voltages up to 1 000 V a.c., as well as in unearthed IT d.c. systems with voltages up to 1 500 V d.c., independent of the measuring principle.This second edition cancels and replaces the first edition published in 1999. It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- scope, normative references and terms and definitions complemented;
- revision of requirements, marking and operating instructions and Clause 6;
- revision of Table 1;
- addition of Annexes A, B and C.