332 CHAPTER 12 Electricity Buildings may be supplied with a variety of different configurations beyond what I have men- tioned here. A qualified electrician is needed to determine what circuits might be appropriate for our equipment. SYSTEM GROUNDING The neutral bus bar at the service entrance (the main panel where power enters the building) is bonded to the grounding bus, and it in turn is grounded to earth by means of a grounding electrode conductor connected to a grounding electrode sunk in earth (e.g., a ground rod, sunken building steel, or a made electrode, which is a large electrode placed in the ground during construction). This is the system ground. The system ground establishes ground potential for the neutral bus. Because the neutral bus is grounded the white wire (neutral) of a distribution system is sometimes called a grounded lead. For utility power, the leads coming from the transformers on the power line provide phase only. The ground and neutral are created at the service equipment where the wires enter the building. In the case of portable generators, the frame of the generator is also bonded to the neutral buss. Depending on the AHJ, 4 a generator may be run as an isolated system without a grounding electrode, or may be required to be grounded via a grounding electrode. The grounding of generators is dis-