Load verification is the process of confirming—through measurement and testing—that a site’s electrical loads and EV charging installation operate within defined limits and behave as designed. In EV charging projects, load verification validates that the configured site power limit, load management, and protection settings actually prevent overloads, maintain stability, and deliver the expected charging performance under real operating conditions.
What Is Load Verification?
Load verification checks both the electrical reality and the control logic after installation or during commissioning. It typically involves:
– Measuring total site demand and EV charging demand under different conditions
– Confirming current and power remain within breaker, feeder, and connection limits
– Verifying the accuracy of load measurement devices (CT clamps, meters)
– Testing load balancing / load curtailment responses to load changes
– Confirming correct phase mapping and neutral connections where relevant
Load verification can be a one-time commissioning activity or a periodic operational check.
Why Load Verification Matters in EV Charging Infrastructure
Even a well-designed system can fail if meters are miswired, CTs are reversed, or settings are incorrect. Load verification helps prevent:
– Unexpected breaker trips and site downtime
– Unsafe overheating of cables, switchgear, or transformers
– Overly aggressive throttling that reduces user satisfaction unnecessarily
– Incorrect billing or reporting due to metering errors
– Non-compliance with site connection agreements or internal safety policies
It also provides confidence for expanding the number of chargers later.
What Is Typically Verified
A robust load verification process commonly checks:
– Site power limit enforcement (does total demand stay below the configured cap?)
– Dynamic load management response time and stability (no oscillation or “hunting”)
– Minimum charging current behavior (EVs don’t repeatedly stop/start)
– Phase loading and phase imbalance in three-phase systems
– Meter accuracy, CT ratios, CT direction, and polling intervals
– Charger setpoint compliance (does the charger actually follow the requested current/power?)
– Fail-safe behavior during network loss (local fallback, default limits)
How Load Verification Is Performed
Common verification methods include:
– Using a portable power analyzer to validate meter readings
– Creating controlled load events (turning on major building loads or simulated loads)
– Starting multiple EV charging sessions to test concurrency behavior
– Checking logs in the CPMS/EMS and charger diagnostics for applied setpoints
– Comparing measured total load vs configured thresholds over time
– Confirming correct wiring against as-built drawings
Verification is most reliable when performed at the same measurement point used for load control (often the main incomer).
Acceptance Criteria and Practical Outcomes
Typical acceptance outcomes from load verification include:
– Confirmed maximum demand does not exceed the safe limit under worst-case scenarios
– Documented response behavior (how quickly charging reduces/increases)
– Verified meter calibration and configuration details
– Confirmed allocation rules (equal share, tenant caps, priority) work as intended
– Identified issues and corrective actions (CT orientation, phase mapping, firmware settings)
This documentation is often useful for internal handover, safety audits, and future expansion planning.
Common Issues Found During Load Verification
Load verification frequently identifies practical commissioning problems:
– CT clamps installed on the wrong conductors or facing the wrong direction
– Incorrect CT ratio settings causing wrong kW calculations
– Misassigned phases leading to unexpected phase imbalance
– Load management polling too slow to react to fast load spikes
– Charger not respecting setpoints due to configuration or backend mismatch
– Overly strict caps causing poor charging performance and unnecessary curtailment
Related Glossary Terms
Load measurement
Load management
Load balancing
Load curtailment
Site power limit
Phase balancing
Commissioning documentation
Energy management system (EMS)
Charge Point Management System (CPMS)
Power throttling