What is the smallest system bonding jumper you can install in the 600-A panel board when using a 500 KVA transformer?

In electrical installations, system bonding jumpers are critical for grounding and ensuring safety in the electrical system. They serve to connect the grounding system to the grounded conductor or to the neutral point of a transformer or service.

For a system connected to a 500 KVA transformer, the sizing of the bonding jumper is dictated by the size of the transformer and the applicable codes, which typically refer to the National Electrical Code (NEC). The NEC provides guidelines for calculating the minimum size of the bonding jumper based on the size of the transformer, the ungrounded conductors, and the size of the grounding conductors.

In this scenario, a 500 KVA transformer has certain specifications that require a specific sizing for safe operation. The NEC indicates that when dealing with transformers of this size, the appropriate bonding jumper will usually be 1/0 copper or equivalent. This is crucial for maintaining the integrity of the grounding system and providing adequate grounding for the equipment.

Thus, the smallest system bonding jumper that meets code requirements for the 600-A panel board when using a 500 KVA transformer is indeed 1/0. This size ensures that the bonding jumper can handle fault currents and maintain safe operation in the event of a fault condition.