Panel Schedule Builder

A panel schedule is a detailed document listing all circuits in an electrical panel, including their descriptions, loads (VA), breaker sizes, and wire specifications. It's required for electrical permits and helps electricians understand the load distribution in a building.

NEC Article 220 provides two methods: the Standard Method calculates each load type separately with specific demand factors, while the Optional Method (for dwellings) uses simplified calculations. General lighting is 3 VA/sq ft, small appliance circuits are 1500 VA each, and the first 3000 VA is at 100% with remainder at 35%.

A demand factor accounts for the fact that not all loads operate simultaneously. For example, NEC 220.42 allows the first 3000 VA of general lighting at 100% demand and the remainder at 35%. This reduces the calculated service size compared to adding up all connected loads.

Main breaker size depends on your total calculated demand load. Most modern homes use 200A service, which handles approximately 48,000 VA. Calculate your total demand using NEC 220 methods, divide by 240V for single-phase, and select the next standard breaker size.

A continuous load operates for 3 hours or more (e.g., lighting, water heaters, EV chargers). NEC 210.20(A) requires sizing conductors and breakers at 125% of continuous loads, meaning a 16A continuous load needs a 20A breaker to prevent overheating.

Wire size is determined by NEC Table 310.16 based on the breaker size and conductor material. For copper at 75C: 14 AWG for 15A, 12 AWG for 20A, 10 AWG for 30A, 8 AWG for 40-50A, and 6 AWG for 60A. Always match wire ampacity to the breaker rating.

Yes, load balancing is important for single-phase 120/240V panels. Unbalanced loads cause higher neutral currents and potential voltage issues. Aim for less than 20% imbalance between phases by distributing similar loads on alternating pole positions.