The Service Point
Sumter EMC's service drop connects to the customer's wiring at the service point. The following drawings show examples for overhead as well as underground services. The customer’s electrician is responsible for all wiring from the service point through the rest of the building. Construction methods and materials may vary from those depicted below.
Figure 1. Service point for an overhead system4
Overhead services as shown in Figure 1 are used when existing utility distribution lines are overhead and where physical constraints (conductor size, span length, and ground clearances) are met.
Figure 2. Service point for an underground system with secondary meter socket installed on side of building.5
Figure 2 is the most commonly used underground construction practice. Almost all residential and small commercial buildings have a meter base installed on an exterior wall, with the service point at the meter base.
Figure 3. Service point for an underground system with secondary junction outside of building.6
Figure 3 is used where the service disconnect is inside the building, and is generally used only in commercial applications. Where the transformer is a significant distance from the building and/or where the NEC requires large conductors, this installation type may reduce the customer's investment in wiring and conduit. The customer must provide and install conduit and conductors between the service point and the service disconnect.
Figure 4. Service point for an underground system with service point at utility transformer.7
Figure 4 is used in commercial applications where the use of a secondary junction provides no economic benefit. The customer must provide and install conduit and conductors between the transformer and the service disconnect.
4 NEC 2002 Handbook, Exhibit 100.11, with modifications
5 NEC 2002 Handbook, Exhibit 230.30, with modifications
6 NEC 2002 Handbook, Exhibit 230.30, with modifications
7 NEC 2002 Handbook, Exhibit 230.30, with modifications
