In Mike Holt's understanding NEC in the grounding section 250.58, it mentions that where a building is supplied with multiple services, the same grounding electrode must be used to ground the enclosures and equipment (so far this makes sense). It also says that there can be dangerous objectionable neutral current flowing through metal parts when multiple service disconnecting means are connected to the same electrode. Isn't this contradictory?
For instance if you have service A in a building and service B in the same building, electrician A would install service A as per Article 250 and electrician B would install service B as per Article 250 (assuming different time frame). But is the book saying that if service A's neutral is connected to the service disconnecting means (via main bonding jumper?) and service B's neutral is connected to the service disconnecting means (via main bonding jumper?) then this is a violation or the book just pointing out that this is potentially bad?
For instance if you have service A in a building and service B in the same building, electrician A would install service A as per Article 250 and electrician B would install service B as per Article 250 (assuming different time frame). But is the book saying that if service A's neutral is connected to the service disconnecting means (via main bonding jumper?) and service B's neutral is connected to the service disconnecting means (via main bonding jumper?) then this is a violation or the book just pointing out that this is potentially bad?
