The Feeder and Service Calculation Settings dialog box is used to manage how loads are calculated for the selected distribution equipment. The chosen calculation method impacts how the various load types assigned to devices are used to determine the calculated load. See the Feeder and Service Calculations article in the knowledge base for more information about how to correctly set the load types, occupancy areas, and demand factors for each load calculation method.
Load Calculation Method: Determines how the service load is calculated, depending upon the type of structure. The Set Default button allows you to change the Default load calculation method setting in the Distribution Equipment options section.
| • | General Commercial or Dwelling Unit, Part III: Use NEC 220 Part III. |
| • | New Restaurant, All Electric: Use the first column in NEC 220.88. |
| • | New Restaurant, Not All Electric: Use the second column in NEC 220.88. |
| • | School: Use NEC 220.86. |
| • | Dwelling Unit: Use NEC 220.82. |
| • | Dwelling Unit, Existing: Use NEC 220.83. |
| • | Multifamily Dwelling (Single units use Part III): Use NEC 220.84 and NEC 220.85. If the distribution equipment serves a single dwelling unit, the calculation uses NEC 220 Part III. The Multifamily Dwelling Units field sets the number of dwelling units used to calculate the diversity. The number of dwelling units on a panel will include the total number on downstream equipment. |
| • | Multifamily Dwelling (Single units use Part IV): Use NEC 220.84 and NEC 220.85. If the distribution equipment serves a single dwelling unit, the calculation uses NEC 220.82. The Multifamily Dwelling Units field sets the number of dwelling units used to calculate the diversity. The number of dwelling units on a panel will include the total number on downstream equipment. |
| • | Multifamily Dwelling (Single units use Existing): Use NEC 220.84 and NEC 220.85. If the distribution equipment serves a single dwelling unit, the calculation uses NEC 220.83. The Multifamily Dwelling Units field sets the number of dwelling units used to calculate the diversity. The number of dwelling units on a panel will include the total number on downstream equipment. |
| • | Marina: Use NEC 220 Part III. Use NEC 220.120 for the Marina / Mobile Home / RV load type. The Shore Power Receptacles field sets the number of shore power receptacles used to calculate the diversity. |
| • | Marina with Sub-Meters: Use NEC 220 Part III. Use NEC Table 220.120 Note 2 for the Marina / Mobile Home / RV load type. The Shore Power Receptacles field sets the number of shore power receptacles used to calculate the diversity. |
| • | Mobile Home Park: Use NEC 220 Part III. Use NEC 550.31 for the Marina / Mobile Home / RV load type. The Mobile Homes field sets the number of mobile homes used to calculate the diversity. |
| • | RV Park: Use NEC 220 Part III. Use NEC 551.73 for the Marina / Mobile Home / RV load type. The Recreational Vehicle Sites field sets the number of sites used to calculate the diversity. |
| • | None (Dynamic footer will be blank): Use NEC 220 Part III. When the schedule is inserted on the drawing, load calculations will not be displayed in the footer. |
Default General Lighting Circuit Value: Sets whether circuits connected to the distribution equipment are automatically designated as General Lighting Circuits as defined by the NEC. Typically, this should be set to No. The Set Default button allows you to change the Default general lighting circuit value setting in the Distribution Equipment options section.
Schedule Block: Sets the schedule block for the distribution equipment. The Set Default button will open the Set Default Schedule Block dialog box. This dialog box allows you to set a default schedule block for the distribution equipment type. Select a schedule block from the available list and press the OK button.
Metered Demand: The current load for an existing building.
Future Demand: The anticipated load for future work. Can be entered in kVA or as a percentage of the calculated load.
Occupancy Areas
This section is used to calculate the demand for occupancy areas on the selected distribution equipment.
Type of Occupancy: The type of occupancy area. The available types are defined in NEC Table 220.42(A).
The Description and Unit Load are based upon the selected type. Select Custom to enter these values manually.
Area: The size of the occupancy area, in square feet.
Description: The description of the occupancy area.
Unit Load: The unit load for the occupancy area. The unit load is based upon the type of occupancy as defined in NEC Table 220.42(A).
Demand Factor: The demand factor for the occupancy area.
| • | Other (Continuous): The demand factor is based upon the All others row of NEC Table 220.45. The lighting will be calculated as a continuous load with a 125% multiplier applied. |
| • | Other (Noncontinuous): The demand factor is based upon the All others row of NEC Table 220.45. The lighting will be calculated as a noncontinuous load with a 100% multiplier applied. |
| • | Dwelling Unit: The demand factor is based upon the Dwelling units row of NEC Table 220.45. |
| • | Hospital: The demand factor is based upon the Hospitals row of NEC Table 220.42 (NEC 2017 and earlier). This demand factor should not be used for areas where the entire lighting is likely to be used at one time, as in operating rooms or dining rooms. |
| • | Hotel or Motel: The demand factor is based upon the Hotels and motels, including apartment houses without provision for cooking by tenants row of NEC Table 220.45. This demand factor should not be used for areas where the entire lighting is likely to be used at one time, as in ballrooms or dining rooms. |
| • | Warehouse (Storage): The demand factor is based upon the Warehouses (storage) row of NEC Table 220.45. |
|
Default load calculation method: Sets the default for the Load Calculation Method setting. Default general lighting circuit value: Sets the default for the Default General Lighting Circuit Value setting. |