EV Charging Standards and NEC 625

Field reference for EV charging technicians. 8 entries, taken from the PlugWatt app.

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Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.

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NEC Article 625

Electric Vehicle Power Transfer System Equipment

Scope

Installation rules for EVSE: branch circuits, feeders, disconnects, ventilation, and energy management.

Key points

625.41 and 625.42: EV charging is a continuous load; size conductors and overcurrent devices at 125 percent of the equipment rated current

625.42 permits sizing to a lower setting when an energy management system limits the load; the 2026 cycle expands this with 625.48 managed maximum demand

625.43: fixed EVSE rated over 60 A or over 150 V to ground requires a readily accessible, lockable disconnecting means

625.54: receptacle installations for EV charging require GFCI protection

Coordinate with 110.14 termination temperature limits and Article 310 ampacity tables

UL 2202

Electric Vehicle Charging System Equipment

Scope

Product safety standard for DC charging equipment: construction, temperature limits, abnormal operation, and output safety.

Key points

Covers the DC charger as a listed product; field modifications void the listing

Temperature and abnormal condition testing back the interlocks techs must never defeat

Pairs with UL 2231 for the personnel protection system requirements

UL 2231

Personnel Protection Systems for EV Supply Circuits

Scope

Requirements for the charging circuit interrupting devices and isolation monitoring that protect people from shock.

Key points

Defines CCID leakage trip behavior for AC supply equipment

Defines isolation monitoring expectations for isolated DC systems

Commissioning should verify the trip test per the manufacturer procedure and record it

SAE J1772

SAE Electric Vehicle Conductive Charge Coupler

Scope

The North American AC coupler and the control pilot signaling every session begins with.

Key points

Defines pilot states A through F and the duty cycle to available current mapping

Defines the proximity circuit and latch behavior

The CCS combo coupler builds on this physical and signaling base

IEC 61851

Electric Vehicle Conductive Charging System

Scope

International system standard defining charging modes 1 through 4 and control functions.

Key points

Mode 2: portable EVSE with in cable protection; Mode 3: dedicated AC EVSE; Mode 4: DC charging with off board rectification

Defines control pilot functions internationally, aligned with J1772 signaling

Referenced by most global charger type approvals

ISO 15118

Road Vehicles to Grid Communication Interface

Scope

High level communication between vehicle and charger: session negotiation, Plug and Charge with certificates, and vehicle to grid services.

Key points

Plug and Charge authenticates the vehicle with an installed certificate so no card or app is needed

Certificate chains involve the vehicle OEM, the mobility operator, and the charge point operator; expiry or a broken chain blocks automatic authorization

Edition 20 adds bidirectional power transfer support

OCPP

Open Charge Point Protocol

Scope

The charger to backend protocol: registration, authorization, transactions, telemetry, firmware, and smart charging.

Key points

1.6J is the deployed workhorse; 2.0.1 adds device management, security profiles, native ISO 15118 support, and richer smart charging; 2.1 is emerging

A charger and backend must agree on version and profile; mismatches present as boot loops or silent feature gaps

Offline behavior, cached authorization lists, and local whitelists are operator policy choices within the protocol

NFPA 70E

Standard for Electrical Safety in the Workplace

Scope

Shock and arc flash risk assessment, energized work permits, lockout tagout, and PPE selection.

Key points

Requires an arc flash risk assessment; DC systems over 100 V need shock and arc flash analysis

DC arcs have no current zero crossing, so they sustain rather than self extinguish; lower peak but longer duration than comparable AC events

Energized work requires justification and an Energized Electrical Work Permit

Verification of absence of voltage is a step of lockout, not an afterthought

These notes come from PlugWatt

Reference notes from PlugWatt, the offline field toolkit for electric vehicle charging installation and service technicians. It works with no cell signal, because the sites do not have any.

Get PlugWatt on the App Store

These notes are a field aid, not a substitute for the governing codes, the stamped drawings, the authority having jurisdiction, or manufacturer manuals. Verify against the current documentation for your installed equipment.