Grounding and Bonding – Part 3（接地和等电位连接-第3部分）.pdfVIP

Grounding and Bonding – Part 3 Introduction and Resources Authors Note: Grounding and Bonding is a confusing subject to the majority of electricians and technicians. As you have seen from the previous two articles on Grounding and Bonding, ground rods have no role in clearing line to pole faults. As it will take many IMSA articles to completely cover NEC Article 250, this IMSA article will cover the introduction to Article 250, suggestions for improved bonding, and additional resources on Grounding and Bonding. By Tom Baker By Tom Baker, Scope of Article 250 250 shall be followed to comply with the performance Puget Sound Section 250.1 covers the scope of this article. Some systems requirements of this section. At first glance this section Electrical are required to be grounded, some are permitted to be appears to have no application for traffic signal and roadway grounded, others are not permitted to be grounded. lighting applications. However, traffic signal and roadway Grounding refers to intentionally connecting a conductor lighting installations have to be installed in a manner that to earth (the grounded conductor). The trade useage and in many cases exceeds the NEC. The NEC contains the incorrect terminology is the neutral conductor. For example, requirements that are necessary for safety [90.1(A)]. Section the white conductor to a traffic signal head is the grounded 250.118 allows a metallic raceway to be used as the conductor, as the neutral carries the unbalanced current of equipment grounding (bonding) conductor,