Electrical Level 3: Module 1 Study Guide
**Load Calculations & Branch/Feeder Circuits**
#### **Section 1: Core Concepts and Definitions**
**1.1 Important Definitions**
* **Branch Circuit:** The circuit conductors between the final overcurrent
device protecting the circuit and the outlet(s). *[NEC Article 100]*
* **Feeder:** All circuit conductors between the service equipment, the source
of a separately derived system, or other power supply source and the final branch-
circuit overcurrent device. *[NEC Article 100]*
* **Continuous Load:** A load where the maximum current is expected to
continue for 3 hours or more. *[NEC Article 100]*
* **Non-Continuous Load:** A load that does not operate for 3 hours or more
continuously.
* **Demand Factor:** The ratio of the maximum demand of a system, or part of
a system, to the total connected load of the system or part of the system.
* `Demand Factor = Maximum Demand / Total Connected Load`
* **Diversity Factor:** The ratio of the sum of the individual maximum demands
of the various subdivisions of a system to the maximum demand of the whole
system.
* **General Lighting Load:** A load calculated based on the square footage of a
dwelling or building, as per NEC Table 220.12 (e.g., 3 VA/sq.ft. for dwellings).
* **Outlet:** A point on the wiring system at which current is taken to supply
utilization equipment. *[NEC Article 100]*
, * **Multioutlet Assembly:** A fixed assembly of receptacles, such as a plug strip
or cord.
**1.2 NEC Article Key Locations**
* **Article 210:** Branch Circuits
* **Article 220:** Branch-Circuit, Feeder, and Service Calculations
* **Article 240:** Overcurrent Protection
* **Article 310:** Conductors for General Wiring
* **Article 430:** Motors, Motor Circuits, and Controllers
---
#### **Section 2: Detailed Calculation Procedures**
**2.1 General Lighting Load Calculation**
* **Method:** Use the square footage of the building.
* **NEC Reference:** Table 220.12.
* **Dwelling Unit:** **3 Volt-Amperes per square foot**.
* **Example:** A 2,000 sq.ft. house.
* General Lighting Load = 2000 sq.ft. × 3 VA/sq.ft. = **6,000 VA**.
* **Note:** For dwelling units, this load is subject to the demand factors in Table
220.42.
**2.2 Small-Appliance and Laundry Branch Circuits (Dwelling Units)**
**Load Calculations & Branch/Feeder Circuits**
#### **Section 1: Core Concepts and Definitions**
**1.1 Important Definitions**
* **Branch Circuit:** The circuit conductors between the final overcurrent
device protecting the circuit and the outlet(s). *[NEC Article 100]*
* **Feeder:** All circuit conductors between the service equipment, the source
of a separately derived system, or other power supply source and the final branch-
circuit overcurrent device. *[NEC Article 100]*
* **Continuous Load:** A load where the maximum current is expected to
continue for 3 hours or more. *[NEC Article 100]*
* **Non-Continuous Load:** A load that does not operate for 3 hours or more
continuously.
* **Demand Factor:** The ratio of the maximum demand of a system, or part of
a system, to the total connected load of the system or part of the system.
* `Demand Factor = Maximum Demand / Total Connected Load`
* **Diversity Factor:** The ratio of the sum of the individual maximum demands
of the various subdivisions of a system to the maximum demand of the whole
system.
* **General Lighting Load:** A load calculated based on the square footage of a
dwelling or building, as per NEC Table 220.12 (e.g., 3 VA/sq.ft. for dwellings).
* **Outlet:** A point on the wiring system at which current is taken to supply
utilization equipment. *[NEC Article 100]*
, * **Multioutlet Assembly:** A fixed assembly of receptacles, such as a plug strip
or cord.
**1.2 NEC Article Key Locations**
* **Article 210:** Branch Circuits
* **Article 220:** Branch-Circuit, Feeder, and Service Calculations
* **Article 240:** Overcurrent Protection
* **Article 310:** Conductors for General Wiring
* **Article 430:** Motors, Motor Circuits, and Controllers
---
#### **Section 2: Detailed Calculation Procedures**
**2.1 General Lighting Load Calculation**
* **Method:** Use the square footage of the building.
* **NEC Reference:** Table 220.12.
* **Dwelling Unit:** **3 Volt-Amperes per square foot**.
* **Example:** A 2,000 sq.ft. house.
* General Lighting Load = 2000 sq.ft. × 3 VA/sq.ft. = **6,000 VA**.
* **Note:** For dwelling units, this load is subject to the demand factors in Table
220.42.
**2.2 Small-Appliance and Laundry Branch Circuits (Dwelling Units)**
