Indicate the general lighting unit load that would be included in the branch-circuit calculations as set forth in NEC Table 220.12.
A restaurant
A schoolroom
A corridor in a school
A hallway in a dwelling
The load to be included for general-purpose convenience receptacles is VA.
The load to be included for an outlet for a specific appliance or load is.
The correct answer and explanation is :
According to the National Electrical Code (NEC) Table 220.12, the general lighting unit load (measured in volt-amperes or VA) is a specified amount that helps to estimate the electrical load in different types of spaces. This allows for accurate branch-circuit calculations, ensuring that the electrical system can handle the expected demand. The following outlines the lighting unit load values for specific spaces:
- Restaurant: The general lighting load for a restaurant is 3 VA per square foot. This value is established considering that restaurants generally require bright lighting to accommodate a variety of tasks such as food preparation, dining areas, and sometimes entertainment areas.
- Schoolroom: For a schoolroom, the NEC specifies 3 VA per square foot. This amount of power is sufficient to account for lighting needs during classes, ensuring that the space remains adequately lit for reading, writing, and other educational activities.
- Corridor in a school: In the case of corridors in a school, the NEC assigns 2 VA per square foot. These corridors typically have lower lighting requirements than classrooms but still require adequate lighting for safety and visibility.
- Hallway in a dwelling: The lighting unit load for a hallway in a dwelling is 2 VA per square foot. Hallways in residences are not high-traffic areas compared to commercial or school spaces, so a lower lighting load is necessary.
- General-purpose convenience receptacles: The load to be included for general-purpose receptacles is 180 VA per outlet. This applies to outlets in spaces like living rooms, kitchens, and offices, where electrical devices are plugged in for various uses (e.g., lamps, televisions, and kitchen appliances).
- Outlet for a specific appliance or load: The load to be included for an outlet that serves a specific appliance or load is typically determined by the rating of the appliance. For example, an electric range or water heater would have a specified VA load based on its wattage, and this value should be included in the calculations for that specific circuit.
The purpose of these lighting unit loads is to provide an estimate of electrical demand and ensure that branch circuits are designed safely and efficiently. Proper calculations based on these values help prevent circuit overloading and ensure that the electrical infrastructure can accommodate all expected loads. The values specified in NEC Table 220.12 are standard and should be followed for compliance with electrical safety regulations.