The heart of a switchboard is the horizontal bus which connects the individual section through bus is available in ratings from 1200–5000 A. JHBB uses aluminum or copper rectangular 0.25 in. x 1.5 in. (6 mm x 38mm) or 0.25 in. x 2 in. (6 mm x 51 mm)/ any other sizes bus bars. Through bus rated 4000 A has eight bus bars per phase.
Bus ampacity ratings have been determined from IEC/IS calculations. This method of current desnsity calculation is the most accurate, since actual tests are used for determining optimal bus sizes.
A 100% neutral bus is provided on 3-phase, 4-wire (3Ø4W) and 1-phase, 3-wire (1Ø3W) systems. Ground bus is standard and matches the type of through bus. Optional, increased-size ground bus is available.