The most expensive way to add EV chargers is to assume every port runs at full power at the same moment, size the service for that worst case, and upgrade. Managed charging takes the opposite approach: it actively limits the chargers’ combined draw so the site stays under a setpoint. Done right, it lets a building host more chargers inside the service it already has — and a reviewer can accept it because the limit is enforced, not hoped for.
What “managed” really means
Uncontrolled charging is sized at nameplate: ten 11.5 kW ports = 115 kW of continuous load, taken at 125% for code. Managed charging (often called automatic load management, ALM, or an energy management system under NEC 750) puts a controller between the building and the chargers. It watches the live load and throttles or staggers sessions so the total never crosses the cap. The chargers still deliver energy — they just take turns instead of all sprinting at once.
When managed charging works
- Many ports, low coincidence. Workplace, dealership, multifamily, and fleet depots where vehicles dwell for hours rarely need all ports at full power at once.
- A real measured peak to build on. The cap has to sit above the building’s existing demand with margin. That requires measured data, not a guess.
- A controller the AHJ will accept. The system must actually enforce the limit and fail safe — and that has to be documented.
When it does not
Managed charging is not a way to pretend load away. If a fleet needs guaranteed simultaneous fast charging to hit a duty cycle, the controlled value is still high and an upgrade may be unavoidable. And a soft cap with no enforcement or logging is not something a careful reviewer will seal. Managed charging earns its savings only when the limit is real and shown.
What a reviewer needs to accept it
To let the code size on the controlled value rather than the nameplate total, the package generally needs: the measured building peak, the chosen setpoint and margin, the control scheme and its fail-safe behavior, the equipment cut sheets, and the NEC 220.87 / NEC 750 basis tying it together. Read the NEC 220.87 explainer for the measured-demand foundation, and how to avoid a service upgrade for the broader decision.
How Ampscale helps
Ampscale models the uncontrolled case and the managed case side by side, shows the headroom each one needs, and assembles the controlled-load basis a reviewer can inspect — all inside a Site Power Record that keeps measured, assumed, and missing inputs separate. Try the free calculator for a first-pass port count, or start a free capacity check.
This is general information, not engineering or legal advice. Automatic load management provisions and their acceptance vary by adopted code and AHJ; a licensed professional must design and seal any system used for permitting.