Master Electrician Exam (NEC)Load CalculationsEasy
A master electrician is performing a standard method load calculation for a single-family dwelling. The dwelling has a 3-wire, 120/240V service. The general lighting and receptacle load is calculated at 8,000 VA. There are four small-appliance branch circuits, each rated at 1500 VA. What is the minimum demand load for the small-appliance branch circuits to be included in the service calculation?
- A7,500 VA
- B3,000 VA
- C6,000 VA
- D4,500 VA
Show answer & explanationAnswer & explanation
Correct answer: C. 6,000 VA
NEC 220.52(A) requires a minimum of 1500 VA for each 2-wire small-appliance branch circuit. For a dwelling unit, two such circuits are required, making the minimum 3000 VA. However, the calculation for the service demand load for small appliance circuits is based on 1500 VA per circuit, and then demand factors are applied. Since there are four small-appliance branch circuits, each assigned 1500 VA for calculation purposes, the total is 4 * 1500 VA = 6000 VA.
Why the other options are wrong
- A. This value does not align with NEC requirements for this scenario.
- B. This would be for two small-appliance circuits, not four.
- D. This value does not align with NEC requirements for this scenario.
Small-Appliance Branch Circuit Demand
For dwelling units, each 2-wire small-appliance branch circuit is assigned a minimum of 1500 VA for load calculation purposes, irrespective of the actual connected load.
- Minimum 1500 VA per circuit.
- Applies to dwelling units.
- Used for service/feeder calculations.
Memory trick: Small appliances get a fixed 'slice' in the load pie.