Branch Circuit Design & Sizing
Continuous load calculations, breaker sizing, conductor selection, and voltage drop requirements for EVSE circuits under the 2026 NEC.
- Apply 2026 NEC Article 120 load calculation requirements for EVSE branch circuit sizing
- Calculate minimum breaker size for a given EV charging load per 2026 NEC Section 120.5(E)
- Select the correct receptacle type for EV charging circuits
- Determine minimum conductor size for EVSE branch circuits using NEC ampacity tables
- Explain voltage drop design goals and their impact on EVSE performance
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Continuous Load & 2026 NEC Article 120
Why EV Charging is a Continuous Load
In NEC terminology, a continuous load is any load where the maximum current is expected to continue for 3 hours or more. EV charging sessions routinely last 4 to 12 hours, making EVSE a textbook continuous load. This classification has implications for circuit design.
Under the 2026 NEC, load calculations for branch circuits, feeders, and services have been relocated from Article 220 to new Article 120. Article 120 consolidates all load calculation rules into a single location for clarity. When studying for the EVITP exam and working under the 2026 NEC, always reference Article 120 for load calculation requirements.
2026 NEC Load Calculation Relocation
Branch-circuit, feeder, and service load calculations moved from Article 220 to Article 120 in the 2026 NEC. The substance of the calculations is updated, and the 125% continuous load multiplier has been removed per Section 120.5(E). Always verify which NEC edition the jurisdiction has adopted.
2026 NEC Section 120.5(E) - Continuous Load Rule Change
The 2026 NEC removes the 125% continuous load multiplier from branch circuit and feeder load calculations. Under Section 120.5(E), continuous loads are no longer required to be multiplied by 125% when sizing overcurrent devices and conductors. The new approach recognizes that modern listed equipment is designed and tested to handle rated continuous loads without the additional thermal margin factor.
Pre-2026 NEC (Article 220)
Continuous load sizing: multiply by 125%
40A EVSE required 50A breaker minimum
Formula: Load x 1.25 = min OCPD/conductor
2026 NEC (Article 120)
125% multiplier removed per Section 120.5(E)
40A EVSE - size to rated load
Verify: Check equipment listing and local adoption
EV charging is always a continuous load because sessions exceed 3 hours. Under the 2026 NEC, load calculations are in Article 120 (relocated from Article 220). Section 120.5(E) removes the 125% continuous load multiplier - always verify which NEC edition the local jurisdiction has adopted before applying sizing rules.