What is the minimum size of each bonding jumper in a section feeding a large hp motor through parallel conduits?

The minimum size of each bonding jumper in a system feeding a large horsepower motor through parallel conduits is determined by the requirements set in the National Electrical Code (NEC) concerning bonding conductors. Specifically, bonding jumpers are necessary for establishing a low-resistance path for fault currents, which is crucial for the safety and operation of the electrical system.

According to NEC guidelines, when calculating the size of bonding jumpers, you must consider the size of the conductors feeding the motor as well as the amount of current the motor will carry. For large motors, it is typically required to have a bonding jumper that is a minimum of the size that can safely handle the maximum load current, and the bonding jumper must also match or be a certain percentage of the feeder conductors.

In this case, selecting the size 1 AWG as the minimum ensures that the bonding path is robust enough to handle fault conditions without exceeding permissible limits. It strikes a balance between sufficient safety and effective electrical performance, aligning with code mandates aimed at protecting equipment and personnel from electrical faults.

Thus, the choice of 1 AWG indicates it adheres to NEC requirements for bonding conductors in high-current applications like large horsepower motors, ensuring safe and reliable operation of the electrical