What April 2026’s MCS Standards and North‑American Tests Really Mean for OEMs, Installers, and AHJs

Why April 2026 feels different for megawatt charging

Two linked developments in April 2026 — publication activity around the Megawatt Charging System (MCS) hardware spec and a formal IEC EVSE project entry — are moving megawatt DC charging from R&D into codified engineering requirements. That shift isn’t just academic: it changes how truckmakers certify vehicles, how charger vendors design hardware, and what electrical inspectors and installers must ask for on plan submittals.

Standards that specify voltages, cooling, and connector behaviour

The IEC has formalized EVSE requirements for megawatt dispensers under IEC 61851‑23‑3, which covers supply‑side voltages up to 1,500 V DC and ties charger rules to the vehicle/connector specification in IEC TS 63379. Separately, the publication of IEC TS 63379 establishes the mechanical and electrical interface expectations for MCS connectors, inlets, and cable assemblies (including liquid cooling and coupling mechanics).

Those documents together give OEMs and EVSE makers a shared technical target: maximum voltages, cooling requirements, mechanical interlocks, and failure‑handling behavior are now defined at international level. CharIN’s April 2025–2026 guidance papers also recommend harmonized ergonomics and interoperability tests so vendors have a clear checklist to design against.

How that accelerates OEM certification and charger design timelines

• Design freeze window for vehicle OEMs: with TS 63379 defining the inlet, cable, and mating interfaces, truck OEMs can commit to a single mechanical/electrical inlet design sooner. That reduces late redesign risk during 2026 production ramp plans.
• Charger vendor convergence: EVSE manufacturers can standardize on the same coupler, liquid‑cooling interfaces, and safety interlocks rather than supporting multiple proprietary guns — lowering engineering and validation cycles.
• Certification pathways: IEC 61851‑23‑3 gives test labs and OEMs a clearer set of EVSE requirements to reference during vehicle/charger interoperability testing, shortening the back‑and‑forth between prototype and certified hardware.

In short: shared technical references turn previously vague design targets into concrete product specifications, cutting ambiguity that typically extends pre‑production qualification by months.

Real world: first North American non‑Tesla commercial MCS session

Practical interoperability moved forward in March 2026 when a Kempower Power Unit with a Mega Satellite dispenser completed a commercial MCS session at EV Realty’s San Bernardino hub. Coverage reports cited a system capable of 1,200 kW with liquid‑cooled cables — an important proof that non‑proprietary MCS hardware can operate in a real depot environment.

That session matters because it demonstrates two things simultaneously: (1) vendors other than OEM‑owned networks can deliver MW‑class finishes, and (2) real‑world vehicle/charger handshakes and thermal control are achievable outside proprietary stacks. Earlier multi‑vendor interoperability test programs (CharIN Testivals and NREL/National labs) already demonstrated handshakes and thermal endurance; the San Bernardino session shows those lab results translate into a commercial depot charging event.

What installers, AHJs, and site engineers must focus on now

With standards and early field tests setting expectations, jurisdictions and installers should move beyond ‘will it work?’ to ‘how will it be made safe and code‑compliant?’ Key practical items:

• Confirm applicable codes and listings: NEC Article 625 remains the U.S. baseline for EV installations, but megawatt DC dispensers are being evaluated under UL families (UL 2202/UL 2594 and new UL projects for high‑current DC components). Always request equipment listing documentation from vendors when reviewing plans.
• Plan for high voltages and MV interfaces: IEC 61851‑23‑3 allows supply‑side voltages up to 1,500 V DC; electrical one‑line diagrams, isolation schemes, short‑circuit protection, and transformer sizing must reflect those ratings rather than assuming standard low‑voltage DC practice.
• Design for liquid cooling and mechanical interlocks: cable handling, cooldown drains, leak detection, and mechanical locking forces required to secure a heavy, liquid‑cooled gun need to appear on installation drawings and maintenance plans (these are explicit in IEC TS 63379 guidance).
• Engage AHJs early: permitting reviews should include the AHJ, utility representative, and vendor so that protection settings, BESS interlocks (if present), and emergency shutdown procedures are agreed before equipment is ordered.

Bottom line

The April 2026 wave of MCS documentation converts design uncertainty into tangible engineering targets. That shrink‑wrap of technical expectations speeds OEM and EVSE timelines, but it also shifts the bottleneck to implementation: code compliance, equipment listings, and careful electrical design are now the gating items for safe, repeatable megawatt charging deployments. Use the published IEC references and field test reports as the specification backbone for vendor selection and plan reviews — and bring local AHJs into the conversation before construction bids are issued.