This part of IEC 61439 defines the specific requirements for distribution boards intended to be operated by ordinary persons (DBO). DBOs have the following criteria: – intended to be operated by ordinary persons (e.g. switching operations and replacing fuse-links), e.g. in domestic (household) applications; – outgoing circuits contain protective devices, intended to be operated by ordinary persons, complying e.g. with IEC 60898-1, IEC 61008, IEC 61009, IEC 62423 and IEC 60269-3; – rated voltage to earth does not exceed 300 V a.c.; – rated current (Inc) of the outgoing circuits does not exceed 125 A and the rated current (InA) of the DBO does not exceed 250 A; – intended for the distribution of electrical energy; – enclosed, stationary; – for indoor or outdoor use. DBOs may also include control and/or signaling devices associated with the distribution of electrical energy. This standard applies to all DBOs whether they are designed, manufactured and verified on a one-off basis or fully standardised and manufactured in quantity. DBOs may be assembled outside the factory of the original manufacturer. This standard does not apply to individual devices and self-contained components, such as circuit breakers, fuse switches, electronic equipment, etc. which will comply with the relevant product standards. This standard does not apply to the specific types of ASSEMBLIES covered by other parts of IEC 61439.