Only one service is permitted for a structure but there are ways to exceed this number identified in the four first-level subdivisions (A) through (D) of this section. A key take-away from this section and its permissions and requirements is the fact that additional services are achievable. A firm handle on 230.2(A) through (D) is needed.
Additional Service Permissions
(A) Special Conditions: this is where you’ll find the permission to add a new service for fire pumps, emergency systems, legally required standby systems, optional standby systems, interconnected electric power production sources, and systems designed for connection to multiple sources of supply for the purpose of enhanced reliability.
(B) Special Occupancies: This is where we have the permission to add a service for two different types of applications. First you have the permission for multiple-occupancy buildings where you don’t have space for service equipment that is accessible to all occupants. Second we have permission for a single building or structure but one that is too large for one service making more than one service necessary. Both of these applications are only possible by special permission given more likely than not by an Authority Having Jurisdiction.
(C) Capacity Requirements: We can’t forget the fact that some applications just have a service need that is too large for just one service. It is here that you have permission to add an additional service or services when the capacity requirements exceed 2000 amperes at 1000 volts or less. There is also recognition for when the serving utility cannot offer the service that is needed for the structure. The code tells us that if the load requirements of a single-phase installation is greater than the serving agency can normally supply through one service we can bring an additional service.
(D) Different Characteristics: Finally we have to recognize that there may be characteristics demanded by the loads in a facility that demand an additional service. The code permits additional services when the application introduces different voltages, frequencies, phases, or even for when there is a need for such things as different rate schedules.
Identification
The other area that is addressed in 230.2, specifically in 230.2(E) Identification, is how to proper identify additional services that may be present at a structure or building. the code requires that any of these buildings or structures that are supplied by more than one service or any combination of branch circuits, feeders, and services, to have a permanent plaque or directory. the plaque or directory has to be installed at each service disconnect location. the plaque or directory must denote the other services, feeders, and branch circuits that tare present that supply the building or structure and the area served by each.
There is a reference in this section to 225.37 also titled “Identification” that is applicable to outside feeders and branch circuits.
Additional Service Entrance Conductors
Finally we have one more item that is addressed by 230.2 which is for those applications where additional service entrance conductors must be pulled.
Section 230.40 gives the permission to pull more than one service entrance conductor through exceptions. Exception number 2 is where you’ll find the permission for more than one service entrance conductor for two to six service disconnecting means. These two to six disconnects must be in separate enclosures, grouped at one location and supply separate loads. the key here is that service entrance conductors are supplied from one service drop, set of overhead service conductors, set of underground service conductors, or service lateral. The reason we see this referenced in 230.2 is because of the fact that in some locations you’ll have more than one set of underground service conductors. In these cases we don’t count that as more than one service.
Section 230.2 tells us that when exception 2 of 230.40 is leveraged, the underground sets of service-conductors that are 1/0 AWG and larger and that are run to the same location and connected together at their supply end but not connected together at their load end are still to be considered to be supplying one service.
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