The electric vehicle (EV) revolution is no longer a distant vision but an unfolding reality reshaping how we think about transportation, energy use, and sustainability. As EV adoption accelerates across North America, ensuring that the infrastructure supporting this transition is fair, accurate, and trustworthy has become paramount. Central to this goal are metering certification programs like the National Type Evaluation Program (NTEP) and the California Type Evaluation Program (CTEP). These programs set the standards for how electricity is measured and billed at commercial EV charging stations, helping build the consumer confidence needed for widespread EV adoption.
For both consumers and charge point operators (CPOs), understanding NTEP and CTEP is essential. These certifications not only govern technical standards but also dictate how a driver’s experience unfolds — from plugging in to payment and receipt issuance. This article explores what NTEP and CTEP are, why they matter, and how they impact commercial EV charging infrastructure today.
The National Type Evaluation Program (NTEP) is a certification system administered by the National Conference on Weights and Measures (NCWM). At its core, NTEP ensures that commercial weighing and measuring devices — including EV chargers — meet the standards outlined in the National Institute of Standards and Technology’s Handbook 44 (NIST HB 44).
Handbook 44 is a highly detailed set of technical requirements that governs everything from gasoline pumps to grocery store scales — and now, EV chargers. The goal is simple: to protect consumers by ensuring they get exactly what they pay for. With EV charging, this means that the kilowatt-hours (kWh) displayed on the charger’s screen — and ultimately billed to the driver — must be measured with proven accuracy.
While the NTEP system has been in place for decades for other industries, its application to EV charging is relatively new. As of January 1, 2025, a majority of U.S. states have either adopted or are in the process of adopting HB 44’s requirements for EV charging equipment. As a result, any commercial charger that bills customers based on the amount of electricity delivered must be NTEP-certified.
This means that a Level 2 charger installed at a public parking lot, workplace, or retail location — where customers pay per kWh — must be tested and certified under the NTEP guidelines. However, chargers that offer free electricity — such as workplace chargers provided as an employee perk — do not require certification, since no transaction is involved.
While NTEP operates at the national level, California has its own, more stringent program: the California Type Evaluation Program (CTEP). Administered by the California Department of Food and Agriculture’s Division of Measurement Standards (DMS), CTEP ensures that commercial measuring devices comply with the state’s uniquely rigorous consumer protection laws.
In the EV charging space, CTEP applies to any public charger that bills by the kWh within the state. Since California has one of the largest EV markets in the world, this state-level certification plays an outsized role in shaping the industry’s best practices nationwide.
CTEP certification for new Level 2 AC chargers has been mandatory since January 1, 2021, and for new DC fast chargers since January 1, 2023. The program requires that every certified device undergo extensive laboratory testing, field inspections, and periodic re-certification to ensure continued accuracy and reliability.
At first glance, NTEP and CTEP may sound like technical hurdles, but they serve a much bigger purpose. As consumers transition from familiar gasoline pumps to electric plugs, their trust in the fairness of the charging transaction is crucial. No driver wants to pay for electricity they didn’t actually receive.
These certification programs guarantee that:
Customers pay only for the energy actually delivered to their vehicle.
Measurements are reliable and consistent across different brands and networks.
Pricing is transparent, with clear information displayed before and during the session.
Receipts fully itemize the energy used, rates charged, and any additional fees.
In this way, NTEP and CTEP help prevent fraud, minimize billing disputes, and strengthen consumer confidence in the reliability of EV charging networks. This is especially important as the industry expands beyond early adopters to mainstream drivers who may be less forgiving of technological hiccups.
To achieve and maintain certification, charge point operators and hardware manufacturers must meet several critical requirements. For example, to comply with NTEP or CTEP guidelines, a commercial EV charger must be able to:
Display Pricing Clearly: All applicable pricing tiers, including peak/off-peak rates, must be shown to the driver before a charging session begins.
Provide Real-Time Cost Information: Throughout the session, the display must show the accumulated cost and energy delivered.
Ensure Accurate Measurement: The meter must be field-testable and meet strict accuracy tolerances.
Maintain Data Integrity: Pricing calculations must persist even during internet outages, ensuring drivers are billed correctly no matter what.
Label Key Specs: Chargers must clearly label their maximum power output and relevant specifications.
Provide Comprehensive Receipts: Receipts must include an itemized breakdown of the session, so customers have a verifiable record of what they paid for.
These requirements create a standardized, trustworthy user experience and reduce the risk of customer complaints.
Beyond measurement accuracy, CTEP compliance influences the broader charging experience in several ways:
Modern drivers expect flexible payment options — from RFID cards to mobile apps to credit card terminals. Chargers must be compatible with standardized protocols like the Open Charge Point Protocol (OCPP) to ensure interoperability across different payment systems. Stations lacking this flexibility often frustrate users and lose business to more reliable competitors.
A charger’s display must be easily readable in various weather and lighting conditions — from glaring sunlight to heavy rain or snow. Level 3 DC fast chargers, in particular, increasingly feature high-definition screens that provide real-time charging status, estimated completion time, and even local area information to keep drivers informed and engaged.
Certified chargers typically offer remote diagnostics and over-the-air (OTA) firmware updates. These capabilities mean CPOs can resolve many technical issues without costly on-site visits. According to industry estimates, OCPP-compliant chargers are up to 40% more efficient at resolving faults than non-compliant units, translating into greater uptime and higher customer satisfaction.
For CPOs, obtaining NTEP or CTEP certification represents an investment in long-term business sustainability. While the upfront testing and compliance costs can be significant, the benefits far outweigh the drawbacks:
Avoid hefty fines and legal liabilities by ensuring all metering devices meet local and national standards.
Drivers are more likely to choose networks that guarantee fair and transparent pricing.
Certification can be a key differentiator in crowded markets, signaling a commitment to quality and reliability.
As states tighten their requirements, having certified equipment from the outset reduces the risk of costly retrofits or replacements.
Achieving certification is not a one-time task but an ongoing process. Here’s how it generally works:
The hardware manufacturer submits a prototype for lab testing to ensure it meets the technical requirements.
Once the device passes lab tests, it undergoes field testing under real-world conditions.
If the device meets all criteria, the NCWM or California DMS issues the official certificate of conformance.
To maintain certification, periodic inspections and recalibrations are required to catch any drifts in measurement accuracy.
CPOs should work closely with trusted equipment manufacturers to ensure their stations remain compliant over time. Choosing hardware that’s already pre-certified can significantly reduce deployment timelines and regulatory headaches.
While the focus here is on the U.S., it’s worth noting that other countries are moving in similar directions. For example, the European Union mandates that public EV chargers provide kWh-based billing and clear pricing disclosures. Germany, in particular, enforces some of the strictest calibration laws in the world for EV chargers.
As the industry matures, harmonizing standards globally could make it easier for drivers to charge confidently wherever they travel. This could also reduce costs for hardware makers by minimizing the number of market-specific device configurations they must produce.
At its heart, the rise of EVs is about more than just cleaner cars — it’s about transforming entire ecosystems of infrastructure, energy production, and consumer behavior. Programs like NTEP and CTEP are invisible but crucial pillars supporting this transformation.
They ensure that the promise of electric mobility — sustainability, savings, and fairness — is not undermined by technical inaccuracies or opaque business practices. For drivers, they offer peace of mind that every kWh paid for is a kWh delivered. For operators and manufacturers, they establish a level playing field built on trust and accountability.
As the U.S. continues its push toward electrified transportation, expect to see more states align with NTEP requirements, and potentially other states adopting California’s CTEP-style standards. In the end, metering accuracy is more than a technical box to check — it’s a promise that the EV industry is ready to deliver on its commitment to a better, cleaner, and fairer future for all.
