Load Management & Energy Systems
Demand management controls, load sharing, energy management systems, current transformers, load shed commands, and the NEC 120% rule.
- Explain how load management controls allow EVSE on smaller circuits
- Describe energy management systems and OCPP network functionality
- Explain the role of current transformers in load monitoring
- Apply the 120% rule for bus rating calculations
- Describe load shed commands and their impact on EVSE operation
Lesson 1
Load Management & Demand Controls
What Is Load Management?
Load management (also called demand management) is a system that controls and limits the total power drawn by multiple EVSE units to stay within the capacity of the electrical infrastructure. Instead of sizing circuits for the full combined load of all EVSE, load management allows installers to share capacity among multiple chargers.
Load management systems can be used when listed and approved demand management controls limit the combined EVSE current. The benefit is significant: instead of installing separate full-capacity circuits for each EVSE, multiple units can share a feeder sized for the managed maximum load.
When Load Management Applies
Load management systems can be used when listed/approved controls limit the combined EVSE current. The feeder is sized based on the managed maximum, not the sum of individual maximums. Reference 2026 NEC Article 120 for load calculation rules.
Future Load Considerations
When installing EVSE, always consider future load growth. A residential panel may have capacity for one EVSE today, but the homeowner may want a second charger in the future. Commercial properties should plan for increasing EV adoption. Installing oversized conduit, extra panel spaces, and adequate feeder capacity reduces the cost of future expansion.
With Load Management
2 x 40A EVSE on shared feeder
Managed max: 40A combined
Feeder: 40A x 1.25 = 50A
Savings: smaller feeder, fewer breakers
Without Load Management
2 x 40A EVSE on separate circuits
Full load: 80A combined
Feeder: 80A x 1.25 = 100A
Cost: larger feeder, more panel space
Load management allows multiple EVSE to share electrical capacity by limiting combined current through listed demand controls. Always plan for future load growth when installing EVSE. Reference 2026 NEC Article 120 for load calculation rules (relocated from Article 220).