Pertains to low-voltage switchgear and controlgear assemblies (type-tested assemblies (TTA), partially type-tested assemblies (PTTA) and non type-tested assemblies (NTTA), with rated voltages that do not exceed 1000 V a.c. at rated frequencies that do not exceed 60 Hz or 1500 V d.c. for use in ships as a supplement to IEC 60439-1.