What is the minimum appropriate bonding jumper for a generator with a 400-ampere output?

To determine the minimum appropriate bonding jumper for a generator with a 400-ampere output, it is essential to consider the requirements set forth by the National Electrical Code (NEC). The NEC outlines that the size of the bonding jumper must be sufficient to ensure that it can adequately carry potential fault currents safely without overheating.

For a generator output of 400 amperes, the NEC references tables that provide guidance on the minimum size of bonding jumpers based on the current ratings. According to the NEC, a bonding jumper for a generator that has an output of this magnitude generally should be at least 1/0 AWG copper. This size is sufficient to ensure that the jumper can handle the fault conditions that could occur with the generator's output.

Therefore, selecting 1/0 AWG is justified based on the requirement to provide a safe and effective electrical bond, enabling proper grounding and reducing the risk of electrical shock or fire due to potential faults. The other options—though larger—exceed the minimum requirements for a 400-ampere output, making 1/0 AWG the correct answer in this case.