Provide a minimum of 75 mm high concrete curb around bus duct floor penetrations. During the installation, inspect the bus bar run for straightness in all planes and make any adjustment necessary for good alignment. The IEC 61439. Check with a ruler. All bolts are in place and tightly secured. The structure is sturdy, with excellent conductivity. This ensures that systems operate reliably without overheating or causing electrical hazards. The International Electrotechnical Commission (IEC) issues globally accepted. The standard busbar spacing is 60 mm. The above advantages are felt especially in cases where many tap-off units of the same performance range are required. 1 One such factor is a global shift in safety regulations to help prevent instances of arc flash. With this system energy can be transported and distributed precisely: from the transformer to the low volta tion, the busbar system is very space-saving. Particularly with changes of direction, there are no ben f up to 253 kA (Ipk) and very low fire.