NTEP (National Type Evaluation Program)

NTEP (National Type Evaluation Program) is a United States certification program that evaluates commercial weighing and measuring devices, including EV chargers, to confirm they measure accurately. It is run by the National Council on Weights and Measures (NCWM), which issues a Certificate of Conformance (CC) for each approved device type. Most states require one before an operator can bill drivers by the kilowatt-hour (kWh) on that charger.

How does NTEP work for EV chargers?

EV chargers are evaluated against Section 3.40, “Electric Vehicle Fueling Systems”, of NIST Handbook 44, the National Institute of Standards and Technology’s code of requirements for commercial measuring devices. Section 3.40 became a permanent code on 1 January 2023. Getting a charger into commercial service takes three steps:

1. Safety listing: The charger needs a safety listing from a nationally recognized testing laboratory, such as UL, before it can enter NTEP.
2. Type evaluation: The manufacturer applies, an NTEP-authorized laboratory tests representative units, and NCWM issues a Certificate of Conformance for that device type.
3. Field inspection: Depending on state requirements, each installed charger is then placed in service, in some states by a registered service agency, and inspected by state or local weights and measures officials.

The certificate covers a charger type, which can include several models, not individual units, and NCWM issues it to the manufacturer. The operator’s part is choosing models that already hold one, and software providers play no part in the application.

What does Handbook 44 require from a charger?

• Accuracy: Within 1.0% at type evaluation and when new (acceptance tolerance), and 2.0% in service (maintenance tolerance). DC chargers placed in service before 1 January 2025 and marked “Class 5” have a 5.0% tolerance until 1 January 2034.
• Display: Energy delivered, unit price and total price, shown at the start of, during and at the end of a session.
• Receipts: A printed or electronic receipt with the energy, unit price, total price, any time-based fees, and the charger and business details.
• Protection against tampering: Settings that affect measurement are protected by a physical seal or an electronic audit trail that records changes.

Why NTEP matters for charging operators

NIST Handbook 130, which most states follow for methods of sale (the rules on what unit a product must be priced in), makes the kilowatt-hour the unit for electricity sold as vehicle fuel. Operators can add a separate, clearly disclosed fee for time or parking, but the energy itself can’t be priced per minute.

Where a state requires type approval for chargers, one without a valid certificate (NTEP, or CTEP in California) can’t be used to bill by the kWh. The certification status of each charger model becomes a go-live check for US sites.

A Certificate of Conformance shows the charger type passed evaluation, but it doesn’t automatically satisfy every state or local requirement. A charge point operator (CPO) expanding across the US checks two things: whether each charger model is certified, and what each state’s inspection, registration and method-of-sale rules require.

For European readers, NTEP plays a role similar to Germany’s Eichrecht, which also requires chargers that bill by energy to measure it accurately.

NTEP vs. CTEP

California runs its own program, the California Type Evaluation Program (CTEP).

The two are not interchangeable. California accepts an NTEP certificate only where the device also meets its own requirements, and a CTEP certificate does not automatically count in other states.

Does NTEP certify charging software?

Not as a separate product, except in California. The NTEP certificate covers the charger type, including its built-in metrology. In California, CTEP can also evaluate charging software, such as app or web activation, together with approved hardware.

The charge point management system (CPMS) works with what the certified charger measures. It sets kWh-based prices, sends the price to the charger for display, bills on the reported energy and produces the receipt. OCPP 2.0.1 includes standard messages for sending pricing information to the charger’s display, which Handbook 44 regulates; OCPP 1.6 handles this only through custom extensions.

Using a CPMS that supports these functions does not by itself establish that the charging equipment meets NTEP requirements.

How AMPECO works with NTEP-certified chargers

AMPECO’s EV charging management platform is hardware-agnostic, so operators can choose certified chargers from the manufacturers they prefer. It supports kWh-based tariffs with separate time-based fees, such as idle fees, and sends drivers an automated receipt after each session, as described on AMPECO’s payments and billing page.

AMPECO has been an Associate Member of NCWM since December 2025. In August 2026 it proposed four amendments to Handbook 44 Section 3.40, including letting chargers without a screen meet the price display requirement through an attached payment terminal or a QR code that opens the operator’s pricing page.

Related terms

• CTEP (California Type Evaluation Program)
• Eichrecht
• EVSE (Electric Vehicle Supply Equipment)
• CPMS (Charge Point Management System)
• OCPP (Open Charge Point Protocol)

Frequently asked questions