What is the minimum size of the copper main bonding jumper for a service that consists of one 350 kcmil copper conductor per phase?

To determine the minimum size of the copper main bonding jumper for a service involving one 350 kcmil copper conductor per phase, it's essential to refer to the National Electrical Code (NEC) guidelines, specifically those found in Article 250, which outlines requirements for grounding and bonding.

The bonding jumper size is primarily dictated by the size of the conductors supplying the service. According to NEC Table 250.66, the minimum size of the equipment bonding jumper can be derived from the size of the largest ungrounded service-entrance conductors. For a service with 350 kcmil copper conductors, the code specifies that the minimum bonding jumper size should be based on the conductor size.

The NEC indicates that for a 350 kcmil copper conductor, the minimum size of the bonding jumper is indeed 2/0 AWG. This size ensures adequate conductivity and safety, preventing potential dangerous voltage differences that could occur in a fault condition. The bonding jumper plays a crucial role in providing a path for fault currents, ensuring that equipment remains grounded, which can protect both the installation and individuals from electrical shock.

In contrast, larger sizes such as 4/0 AWG and 3/0 AWG may provide an even