IEC 60439-3 Ed. 1.2 b:2001, Low-voltage switchgear and controlgear assemblies - Part 3: Particular requirements for low-voltage switchgear and ... persons have access for their use - Di

This standard gives supplementary requirements for enclosed distribution boards (DBU), which are stationary, type-tested assemblies (TTA) for indoor use, containing protective devices and intended for use either in domestic (household) applications or in other places where unskilled persons have access for their use.