Distribution System

Busbar Information

Plates for Mounting on Busbars

Determining the spacing between busbar supports (LA9ZX01495 and LA9ZX01485), according to IEC 60439-1.Depending on the short-circuit current.*

Short-circuit strength diagram according to UL845 (LA9ZX01508).

Load Resistance of Busbar Assemblies in IEC Applications

For an Ambient Temperature of 35°C and a Busbar Temperature of 65°C

Cross Section	mm (in.)	12 x 5 (0.47 x 0.20)	15 x 5 (0.59 x 0.20)	20 x 5 (0.79 x 0.20)	25 x 5 (0.98 x 0.20)	30 x 5 (1.18 x 0.20)	12 x 10 (0.47 x 0.39)	20 x 10 (0.79 x 0.39)	30 x 10 (1.18 x 0.39)
Permissible current	A	200	250	320	400	450	360	520	630

In the event of changes in climatic conditions, the following curve indicates the correction factor K2 to be applied.

Example: In normal operating conditions, a tinned busbar of 30 x 10 can permanently withstand 630 A.

For a load of 800 A, the correction factor K2 to be applied will be 1.3 (800/630). As a result, the temperature rise in the busbars will reach 82.5°C.