IEC 61439-3

IEC 61439-3:2024 defines the specific requirements for distribution boards intended to be operated by ordinary persons (abbreviated DBO throughout this document, see 3.1.101) as follows:
- assemblies intended to be operated by ordinary persons (e.g. switching operations and replacing fuse-links), e.g. in domestic (household) applications;
- assemblies containing outgoing circuits with protective devices intended to be operated by ordinary persons, complying e.g. with IEC 60898-1, the IEC 61008 series, the IEC 61009 series, IEC 62606, IEC 62423 and IEC 60269-3;
- assemblies for applications where the nominal voltage to earth does not exceed 300 V AC (see Table G.1 of IEC 61439-1:2020);
NOTE The voltage limits for DC applications are under consideration.
- assemblies with a rated current (Inc) of the outgoing circuits not exceeding 125 A and a rated current (InA) not exceeding 250 A;
- assemblies intended for use in connection with the generation, transmission, distribution and conversion of electrical energy, and for the control of equipment consuming electrical energy and for associated data processing;
- enclosed, stationary assemblies;
- assemblies for indoor or outdoor use.
This second edition cancels and replaces the first edition published in 2012. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) alignment with the structure of IEC 61439-1:2020;
b) inclusion in the scope of more examples of the type of protection and control devices;
c) deletion of type A and Type B DBOs;
d) addition of a new Annex BB related to DBOs used in a prosumer’s electrical installation (PEI);
e) addition of a new Annex CC related to rated current of a DBO with additional source of supply in parallel/simultaneously with another source that is connected to the DBO e.g. PV.