Prozessleitfaden — WiM

WiM: Wie der Wechsel des Messstellenbetreibers funktioniert Das Herzstück von leitnetz

Seit 2017 können Verbraucher in Deutschland ihren Messstellenbetreiber frei wählen. WiM (Wechselprozesse im Messwesen) ist das BNetzA-Regelwerk für jeden Schritt dieses Prozesses.

UTILMDAPERAK A7/A8MSCONSINVOIC6 Sub-ProcessesMsbG 2017

Was ist WiM?

The complete rulebook for meter operator changes

WiM stands for Wechselprozesse im Messwesen — the processes for changing meter operators. Defined by the BNetzA (Federal Network Agency), WiM regulates all communication between meter operators (MSB), grid operators (NB), and default meter operators (gMSB). Compliance is mandatory for every market participant in the German energy sector.

Beginn MSB

A competitive MSB starts service at a location. The MSB sends UTILMD (PI 55042) to the NB. Lead time: 15 working days minimum. This is the most common WiM process.

Ende MSB

An MSB ends service at a location. Sends UTILMD (PI 55051) to the NB. Lead time: 20 working days. The gMSB (default operator) must take over afterward.

Kuendigung

The NB cancels an MSB assignment. The NB sends UTILMD to the MSB. The MSB must hand over all meters to the gMSB. This is an involuntary process.

Verpflichtung gMSB

The NB obligates the default meter operator (gMSB) to take over. The NB sends UTILMD to the gMSB. This process ensures no location is ever left without a meter operator.

Geraetewechsel

Physical meter replacement at a location. The MSB notifies the NB via UTILMD when a meter device is swapped, upgraded, or replaced due to failure.

Geraeteuebernahme

Device takeover when one MSB takes over another MSB's physical meters. This happens when the new MSB wants to reuse the existing hardware instead of installing new devices.

Der Beginn-MSB-Prozess

Walk through the most common WiM process: a competitive meter operator starts service at a new location.

Beginn MSB Process (7 steps)

Klicken Sie auf einen Schritt oder drücken Sie Abspielen

Simulator: Beginn-MSB-Austausch

Watch the EDIFACT messages flow between the meter operator and the grid operator. Each message triggers validation, acknowledgement, and status updates.

Beginn MSB (MSB → NB)

MSBMeter Operator

NBGrid Operator

Klicken Sie auf 'Prozess starten', um den Austausch zu beobachten

Two-layer validation

Every message passes through two independent validation layers before dispatch. Business rules (67 validators in wim-service) check domain logic like lead times and partner authorization. EDIFACT structural rules (edifact-service) check segment presence and field formats. Both must pass.

Schlüsselkonzepte

Rules That Govern Every WiM Process

Understanding these concepts is essential for anyone working with meter operator switching in the German energy market.

Lead Times

15 working days for Beginn, 20 working days for Ende. Weekends and German public holidays are excluded from the count. Missing a lead time deadline makes the request invalid and the NB must reject it.

Rejection Codes

Z10 (location unknown), Z12 (different MSB already assigned), Z14 (date conflict), Z99 (other reason). The NB must use specific codes from the defined set. Free-text rejections are not permitted by the specification.

gMSB Fallback

If a competitive MSB ends service and no replacement is assigned, the gMSB (default operator) is legally obligated to take over. The NB triggers this via the Verpflichtung process. No location may be left without a meter operator.

Two-Layer Validation

Business rules (wim-service: 67 validators across 12 process indicators) check domain logic. EDIFACT structural rules (edifact-service: .edimap specs) check message syntax. Both layers must pass before any message is dispatched.

What leitnetz does

This Is What leitnetz Automates

Users fill a clean wizard form. leitnetz handles everything else: form validation, EDIFACT generation, multi-layer validation, peer delivery, acknowledgement generation, and status tracking across all market roles.

All 6 WiM Sub-Processes

Beginn, Ende, Kuendigung, Verpflichtung, Geraetewechsel, and Geraeteuebernahme. Every process has an initiation wizard and a response wizard.

All Market Roles

MSB, NB, and gMSB each run in isolated instances with their own database. Cross-role communication happens via EDIFACT through the edifact-service.

Automatic APERAK/CONTRL

Acknowledgements are generated automatically after inbound processing. Strom uses APERAK A7/A8. Gas uses CONTRL action_code 7/8. No manual message handling required.

67 Business Validators

Lead time checks, partner GLN existence, role-pair authorization, required fields, cross-field consistency, and document date validation. All run before dispatch.

Full Audit Trail

Every UTILMD, APERAK, MSCONS, and INVOIC is stored with correlation IDs and timestamps. Every message status transition is tracked from VALIDATED through DELIVERED.

Status Tracking

Cases progress through a defined state machine: VALIDATED, DISPATCHED, DELIVERED. Both sender and receiver see real-time status updates via SSE.

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