Power frequency magnetic fields around busbar trunking risers

Busbar systems are often employed as a riser for power distribution in large buildings. The magnetic fields around typical busbar trunking systems are evaluated in this paper via numerical and experimental investigation. Galvanized iron enclosure of the busbar trunking system is approximately modeled as a linear enclosure with a constant equivalent relative permeability. The modeling effectiveness is validated. It is found that the equivalent relative permeability is almost linearly proportional the magnitude of the carried current. Harmonic frequency magnetic fields are also discussed.