Derive device voltages from project settings

docs/circuit-list-editor-api.md

@@ -150,7 +150,11 @@ synchronizes linked circuit rows implicitly.
   - response:
     `{ "project": { ... }, "revision": { ... }, "history": { ... } }`
   - persistent Undo/Redo restores metadata, voltage values and the enabled
-    distribution-board supply types together
+    distribution-board supply types together; project-device and circuit
+    voltages are recalculated from the restored project settings in the same
+    transaction
+  - project-device and circuit voltage are derived values and are not accepted
+    as editable frontend fields
   - at least one of `AV`, `SV`, `EV`, `USV`, `MSR`, `SiBe` must be enabled;
     a supply type currently used by a distribution board cannot be disabled
   - unchanged values are rejected without creating a revision; a stale

docs/project-history-and-external-model-architecture.md

@@ -265,7 +265,9 @@ Completed foundation:
   snapshots in the same transaction
 - `project.update-settings` persists both project voltage defaults, its exact
   inverse, revision and history transition atomically; the project page and
-  existing PUT route require the current expected revision
+  existing PUT route require the current expected revision; the same
+  transaction derives every project-device and circuit voltage again, so
+  Undo/Redo cannot leave mixed voltage states
 - `distribution-board.insert` persists the complete generated board, circuit
   list and default-section structure with stable ids; its delete inverse
   refuses changed or populated structures and the project-page POST tracks the

docs/spec/08-current-product-backlog.md

@@ -35,21 +35,27 @@ requirements and intended sequencing, not proof of implementation.
 - Persist changes through project commands so they remain undoable after a
   restart.
 
-## Device Voltage Defaults
+## Device Voltage Derivation
 
 - Derive voltage from the selected phase type and the project settings:
   - single-phase uses the project's single-phase voltage;
   - three-phase uses the project's three-phase voltage.
-- Apply this default consistently when creating global devices, project
+- Voltage is not editable on global devices, project devices or circuits.
-  devices and manual circuit-list entries.
+  Global devices store only their phase; copying one into a project derives
-- Define explicit override behavior before implementation so a user-entered
+  the target project's voltage.
-  exceptional voltage is not silently overwritten when phase type or project
+- Project-device voltage follows its phase. Circuit voltage follows the
-  settings change.
+  section phase; an unassigned circuit is three-phase only when all assigned
+  device rows with a valid phase are three-phase.
+- Changing project voltage settings updates all project devices and circuits
+  atomically in the same persistent Undo/Redo step.
+- Database migration `0019` and snapshot schema version `5` normalize older
+  stored values. Version-four and older imports remain supported and are
+  normalized while being upgraded.
 
 ## Recommended Sequence
 
 1. Distribution-board floor and supply fields.
-2. Device voltage default and override semantics.
+2. Device voltage derivation without overrides.
 3. Snapshot-to-revision descriptions and history presentation.
 
 The Revit/CSV/IFCGUID round-trip remains a separate jointly planned phase and

src/app/projects/page.tsx

@@ -24,7 +24,6 @@ const emptyGlobalDevice: CreateGlobalDeviceInput = {
   quantity: 1,
   installedPowerPerUnitKw: 0.1,
   demandFactor: 1,
-  voltageV: 230,
   phaseCount: 1,
   powerFactor: 1,
   note: "",
@@ -49,7 +48,6 @@ export default function ProjectsPage() {
     quantity: "1",
     installedPowerPerUnitKw: "0.1",
     demandFactor: "1",
-    voltageV: "230",
     phaseCount: "1",
     powerFactor: "1",
     note: "",
@@ -153,7 +151,6 @@ export default function ProjectsPage() {
       quantity: Number(globalDeviceForm.quantity),
       installedPowerPerUnitKw: Number(globalDeviceForm.installedPowerPerUnitKw),
       demandFactor: Number(globalDeviceForm.demandFactor),
-      voltageV: toOptionalNumber(globalDeviceForm.voltageV),
       phaseCount: globalDeviceForm.phaseCount === "3" ? 3 : 1,
       powerFactor: toOptionalNumber(globalDeviceForm.powerFactor),
       note: globalDeviceForm.note.trim() || undefined,
@@ -170,7 +167,6 @@ export default function ProjectsPage() {
         quantity: String(emptyGlobalDevice.quantity),
         installedPowerPerUnitKw: String(emptyGlobalDevice.installedPowerPerUnitKw),
         demandFactor: String(emptyGlobalDevice.demandFactor),
-        voltageV: String(emptyGlobalDevice.voltageV ?? ""),
         phaseCount: String(emptyGlobalDevice.phaseCount ?? 1),
         powerFactor: String(emptyGlobalDevice.powerFactor ?? ""),
         note: emptyGlobalDevice.note ?? "",
@@ -207,7 +203,6 @@ export default function ProjectsPage() {
       quantity: device.quantity,
       installedPowerPerUnitKw: device.installedPowerPerUnitKw,
       demandFactor: device.demandFactor,
-      voltageV: device.voltageV ?? undefined,
       phaseCount: device.phaseCount ?? undefined,
       powerFactor: device.powerFactor ?? undefined,
       note: device.note ?? undefined,

src/db/migrations/0019_normalize_project_voltages.sql

@@ -0,0 +1,48 @@
+UPDATE `global_devices`
+SET `voltage_v` = NULL;
+--> statement-breakpoint
+UPDATE `project_devices` AS `pd`
+SET `voltage_v` = CASE
+  WHEN `pd`.`phase_type` = 'three_phase' THEN `p`.`three_phase_voltage_v`
+  ELSE `p`.`single_phase_voltage_v`
+END
+FROM `projects` AS `p`
+WHERE `p`.`id` = `pd`.`project_id`;
+--> statement-breakpoint
+WITH `derived_circuit_voltages` AS (
+  SELECT
+    `c`.`id` AS `circuit_id`,
+    CASE
+      WHEN `cs`.`key` = 'three_phase' THEN `p`.`three_phase_voltage_v`
+      WHEN `cs`.`key` IN ('lighting', 'single_phase') THEN `p`.`single_phase_voltage_v`
+      WHEN EXISTS (
+        SELECT 1
+        FROM `circuit_device_rows` AS `three_phase_row`
+        WHERE `three_phase_row`.`circuit_id` = `c`.`id`
+          AND `three_phase_row`.`phase_type` = 'three_phase'
+      ) AND NOT EXISTS (
+        SELECT 1
+        FROM `circuit_device_rows` AS `other_row`
+        WHERE `other_row`.`circuit_id` = `c`.`id`
+          AND `other_row`.`phase_type` = 'single_phase'
+      ) THEN `p`.`three_phase_voltage_v`
+      ELSE `p`.`single_phase_voltage_v`
+    END AS `derived_voltage`
+  FROM `circuits` AS `c`
+  INNER JOIN `circuit_lists` AS `cl`
+    ON `cl`.`id` = `c`.`circuit_list_id`
+  INNER JOIN `projects` AS `p`
+    ON `p`.`id` = `cl`.`project_id`
+  INNER JOIN `circuit_sections` AS `cs`
+    ON `cs`.`id` = `c`.`section_id`
+)
+UPDATE `circuits`
+SET `voltage` = (
+  SELECT `derived_voltage`
+  FROM `derived_circuit_voltages`
+  WHERE `circuit_id` = `circuits`.`id`
+)
+WHERE `id` IN (
+  SELECT `circuit_id`
+  FROM `derived_circuit_voltages`
+);

src/db/migrations/meta/_journal.json

@@ -134,6 +134,13 @@
       "when": 1785308458789,
       "tag": "0018_fancy_argent",
       "breakpoints": true
+    },
+    {
+      "idx": 19,
+      "version": "6",
+      "when": 1785310907349,
+      "tag": "0019_normalize_project_voltages",
+      "breakpoints": true
     }
   ]
 }

src/db/repositories/circuit-device-row-move-project-command.repository.ts

@@ -20,11 +20,14 @@ import { circuitLists } from "../schema/circuit-lists.js";
 import { circuitSections } from "../schema/circuit-sections.js";
 import { circuits } from "../schema/circuits.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { updateDerivedCircuitVoltage } from "./project-voltage.persistence.js";
+import { resolveCircuitVoltage } from "./project-voltage.persistence.js";
 
 interface PersistedMoveRow {
   id: string;
   circuitId: string;
   sortOrder: number;
+  phaseType: string | null;
 }
 
 export class CircuitDeviceRowMoveProjectCommandRepository
@@ -85,6 +88,7 @@ export class CircuitDeviceRowMoveProjectCommandRepository
       );
       this.applyMoves(database, command.payload.moves);
       this.updateReserveStates(database, circuitIds);
+      this.updateVoltages(database, projectId, circuitIds);
       return inverse;
     }
 
@@ -94,7 +98,16 @@ export class CircuitDeviceRowMoveProjectCommandRepository
     const { targetCircuit, targetCircuitAction, moves } =
       command.payload;
     const rowsById = this.loadExpectedRows(database, moves);
-    this.assertCircuitLocation(database, projectId, targetCircuit);
+    const appliedTargetCircuit = {
+      ...targetCircuit,
+      voltage: resolveCircuitVoltage(
+        database,
+        projectId,
+        targetCircuit.sectionId,
+        moves.map((move) => rowsById.get(move.rowId)?.phaseType)
+      ),
+    };
+    this.assertCircuitLocation(database, projectId, appliedTargetCircuit);
 
     if (targetCircuitAction === "create") {
       const sourceCircuitIds = [
@@ -106,13 +119,13 @@ export class CircuitDeviceRowMoveProjectCommandRepository
         sourceCircuitIds,
         targetCircuit.circuitListId
       );
-      this.assertTargetCircuitAvailable(database, targetCircuit);
+      this.assertTargetCircuitAvailable(database, appliedTargetCircuit);
-      this.insertTargetCircuit(database, targetCircuit);
+      this.insertTargetCircuit(database, appliedTargetCircuit);
 
       const inverse =
         createCircuitDeviceRowMoveWithNewCircuitProjectCommand(
           "delete",
-          targetCircuit,
+          appliedTargetCircuit,
           this.reverseMoves(moves, rowsById)
         );
       this.applyMoves(database, moves);
@@ -120,12 +133,16 @@ export class CircuitDeviceRowMoveProjectCommandRepository
         ...sourceCircuitIds,
         targetCircuit.id,
       ]);
+      this.updateVoltages(database, projectId, [
+        ...sourceCircuitIds,
+        targetCircuit.id,
+      ]);
       return inverse;
     }
 
     this.assertTargetCircuitUnchanged(
       database,
-      targetCircuit,
+      appliedTargetCircuit,
       moves.map((move) => move.rowId)
     );
     const destinationCircuitIds = [
@@ -140,7 +157,7 @@ export class CircuitDeviceRowMoveProjectCommandRepository
     const inverse =
       createCircuitDeviceRowMoveWithNewCircuitProjectCommand(
         "create",
-        targetCircuit,
+        appliedTargetCircuit,
         this.reverseMoves(moves, rowsById)
       );
     this.applyMoves(database, moves);
@@ -148,6 +165,11 @@ export class CircuitDeviceRowMoveProjectCommandRepository
       targetCircuit.id,
       ...destinationCircuitIds,
     ]);
+    this.updateVoltages(
+      database,
+      projectId,
+      destinationCircuitIds
+    );
     const deleted = database
       .delete(circuits)
       .where(
@@ -169,6 +191,16 @@ export class CircuitDeviceRowMoveProjectCommandRepository
     return inverse;
   }
 
+  private updateVoltages(
+    database: AppDatabase,
+    projectId: string,
+    circuitIds: string[]
+  ) {
+    for (const circuitId of new Set(circuitIds)) {
+      updateDerivedCircuitVoltage(database, projectId, circuitId);
+    }
+  }
+
   private loadExpectedRows(
     database: AppDatabase,
     moves: CircuitDeviceRowMoveAssignment[]
@@ -179,6 +211,7 @@ export class CircuitDeviceRowMoveProjectCommandRepository
         id: circuitDeviceRows.id,
         circuitId: circuitDeviceRows.circuitId,
         sortOrder: circuitDeviceRows.sortOrder,
+        phaseType: circuitDeviceRows.phaseType,
       })
       .from(circuitDeviceRows)
       .where(inArray(circuitDeviceRows.id, rowIds))

src/db/repositories/circuit-device-row-project-command.repository.ts

@@ -22,6 +22,7 @@ import {
   type CircuitDeviceRowPatchInput,
 } from "./circuit-device-row.persistence.js";
 import { executeProjectCommandTransactionWithAppliedForward } from "./project-command-transaction.persistence.js";
+import { updateDerivedCircuitVoltage } from "./project-voltage.persistence.js";
 
 type CircuitDeviceRow = typeof circuitDeviceRows.$inferSelect;
 
@@ -117,6 +118,13 @@ export class CircuitDeviceRowProjectCommandRepository
     if (update.changes !== 1) {
       throw new Error("Circuit device row changed before command execution.");
     }
+    if (patch.phaseType !== undefined) {
+      updateDerivedCircuitVoltage(
+        tx,
+        input.projectId,
+        current.circuitId
+      );
+    }
 
     return {
       forward: appliedForward,

src/db/repositories/circuit-device-row-structure-project-command.repository.ts

@@ -22,6 +22,7 @@ import {
   toCircuitDeviceRowSnapshot,
 } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { updateDerivedCircuitVoltage } from "./project-voltage.persistence.js";
 
 export class CircuitDeviceRowStructureProjectCommandRepository
   implements CircuitDeviceRowStructureProjectCommandStore
@@ -101,6 +102,7 @@ export class CircuitDeviceRowStructureProjectCommandRepository
     if (circuitUpdate.changes !== 1) {
       throw new Error("Circuit changed before device-row insertion.");
     }
+    updateDerivedCircuitVoltage(database, projectId, row.circuitId);
 
     return createCircuitDeviceRowDeleteProjectCommand(
       row.id,
@@ -153,6 +155,11 @@ export class CircuitDeviceRowStructureProjectCommandRepository
     if (circuitUpdate.changes !== 1) {
       throw new Error("Circuit changed before device-row deletion.");
     }
+    updateDerivedCircuitVoltage(
+      database,
+      projectId,
+      expectedCircuitId
+    );
 
     return createCircuitDeviceRowInsertProjectCommand(
       toCircuitDeviceRowSnapshot(row)

src/db/repositories/circuit-project-command.repository.ts

@@ -18,7 +18,9 @@ import {
   toCircuitPatchValues,
   type CircuitPatchPersistenceInput,
 } from "./circuit.persistence.js";
-import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { executeProjectCommandTransactionWithAppliedForward } from "./project-command-transaction.persistence.js";
+import { resolveCircuitVoltage } from "./project-voltage.persistence.js";
+import { circuitDeviceRows } from "../schema/circuit-device-rows.js";
 
 type CircuitRow = typeof circuits.$inferSelect;
 
@@ -30,7 +32,7 @@ export class CircuitProjectCommandRepository
   executeUpdate(input: ExecuteCircuitUpdateCommandInput) {
     assertCircuitUpdateProjectCommand(input.command);
 
-    return executeProjectCommandTransaction(
+    return executeProjectCommandTransactionWithAppliedForward(
       this.database,
       input,
       (tx) => this.applyCommand(tx, input)
@@ -71,14 +73,44 @@ export class CircuitProjectCommandRepository
       ])
     ) as CircuitPatchPersistenceInput;
     this.assertSectionInCircuitList(tx, current, patch.sectionId);
+    if (input.source === "user") {
+      if (
+        input.command.payload.changes.every(
+          (change) => change.field === "voltage"
+        )
+      ) {
+        throw new Error("Circuit voltage is derived and cannot be edited.");
+      }
+      const devicePhaseTypes = tx
+        .select({ phaseType: circuitDeviceRows.phaseType })
+        .from(circuitDeviceRows)
+        .where(eq(circuitDeviceRows.circuitId, current.id))
+        .all()
+        .map((row) => row.phaseType);
+      const derivedVoltage = resolveCircuitVoltage(
+        tx,
+        input.projectId,
+        patch.sectionId ?? current.sectionId,
+        devicePhaseTypes
+      );
+      if (derivedVoltage === current.voltage) {
+        delete patch.voltage;
+      } else {
+        patch.voltage = derivedVoltage;
+      }
+    }
     this.assertUniqueEquipmentIdentifier(
       tx,
       current,
       patch.equipmentIdentifier
     );
 
+    const appliedForward = createCircuitUpdateProjectCommand(
+      current.id,
+      patch as CircuitUpdatePatch
+    );
     const inversePatch = Object.fromEntries(
-      input.command.payload.changes.map((change) => [
+      appliedForward.payload.changes.map((change) => [
         change.field,
         getCircuitFieldValue(current, change.field),
       ])
@@ -97,7 +129,7 @@ export class CircuitProjectCommandRepository
       throw new Error("Circuit changed before command execution.");
     }
 
-    return inverse;
+    return { forward: appliedForward, inverse };
   }
 
   private assertSectionInCircuitList(

src/db/repositories/circuit-structure-project-command.repository.ts

@@ -23,6 +23,7 @@ import {
   toCircuitDeviceRowSnapshot,
 } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { resolveCircuitVoltage } from "./project-voltage.persistence.js";
 
 export class CircuitStructureProjectCommandRepository
   implements CircuitStructureProjectCommandStore
@@ -77,6 +78,19 @@ export class CircuitStructureProjectCommandRepository
     snapshot: CircuitSnapshot
   ) {
     this.assertCircuitLocation(database, projectId, snapshot);
+    if (source === "user") {
+      const derivedVoltage = resolveCircuitVoltage(
+        database,
+        projectId,
+        snapshot.sectionId,
+        snapshot.deviceRows.map((row) => row.phaseType)
+      );
+      if (snapshot.voltage !== derivedVoltage) {
+        throw new Error(
+          "Circuit voltage must match the project phase voltage."
+        );
+      }
+    }
 
     const existingCircuit = database
       .select({ id: circuits.id })

src/db/repositories/global-device.repository.ts

@@ -26,7 +26,7 @@ export class GlobalDeviceRepository {
       quantity: input.quantity,
       installedPowerPerUnitKw: input.installedPowerPerUnitKw,
       demandFactor: input.demandFactor,
-      voltageV: input.voltageV ?? null,
+      voltageV: null,
       phaseCount: input.phaseCount ?? null,
       powerFactor: input.powerFactor ?? null,
       note: input.note ?? null,
@@ -45,7 +45,7 @@ export class GlobalDeviceRepository {
         quantity: input.quantity,
         installedPowerPerUnitKw: input.installedPowerPerUnitKw,
         demandFactor: input.demandFactor,
-        voltageV: input.voltageV ?? null,
+        voltageV: null,
         phaseCount: input.phaseCount ?? null,
         powerFactor: input.powerFactor ?? null,
         note: input.note ?? null,

src/db/repositories/project-device-project-command.repository.ts

@@ -12,7 +12,8 @@ import type {
 } from "../../domain/ports/project-device-project-command.store.js";
 import type { AppDatabase } from "../database-context.js";
 import { projectDevices } from "../schema/project-devices.js";
-import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { executeProjectCommandTransactionWithAppliedForward } from "./project-command-transaction.persistence.js";
+import { resolveProjectDeviceVoltage } from "./project-voltage.persistence.js";
 
 type ProjectDeviceRow = typeof projectDevices.$inferSelect;
 
@@ -24,7 +25,7 @@ export class ProjectDeviceProjectCommandRepository
   executeUpdate(input: ExecuteProjectDeviceUpdateCommandInput) {
     assertProjectDeviceUpdateProjectCommand(input.command);
 
-    return executeProjectCommandTransaction(
+    return executeProjectCommandTransactionWithAppliedForward(
       this.database,
       input,
       (tx) => this.applyCommand(tx, input)
@@ -60,8 +61,40 @@ export class ProjectDeviceProjectCommandRepository
         change.value,
       ])
     ) as ProjectDeviceUpdatePatch;
+    if (input.source === "user") {
+      if (
+        input.command.payload.changes.every(
+          (change) => change.field === "voltageV"
+        )
+      ) {
+        throw new Error(
+          "Project-device voltage is derived and cannot be edited."
+        );
+      }
+      const targetPhaseType = patch.phaseType ?? current.phaseType;
+      if (
+        targetPhaseType !== "single_phase" &&
+        targetPhaseType !== "three_phase"
+      ) {
+        throw new Error("Project-device phase type is invalid.");
+      }
+      const derivedVoltage = resolveProjectDeviceVoltage(
+        tx,
+        input.projectId,
+        targetPhaseType
+      );
+      if (derivedVoltage === current.voltageV) {
+        delete patch.voltageV;
+      } else {
+        patch.voltageV = derivedVoltage;
+      }
+    }
+    const appliedForward = createProjectDeviceUpdateProjectCommand(
+      current.id,
+      patch
+    );
     const inversePatch = Object.fromEntries(
-      input.command.payload.changes.map((change) => [
+      appliedForward.payload.changes.map((change) => [
         change.field,
         getProjectDeviceFieldValue(current, change.field),
       ])
@@ -87,7 +120,7 @@ export class ProjectDeviceProjectCommandRepository
       );
     }
 
-    return inverse;
+    return { forward: appliedForward, inverse };
   }
 }
 

src/db/repositories/project-device-row-sync-project-command.repository.ts

@@ -16,6 +16,7 @@ import { circuitLists } from "../schema/circuit-lists.js";
 import { circuits } from "../schema/circuits.js";
 import { projectDevices } from "../schema/project-devices.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { updateDerivedCircuitVoltage } from "./project-voltage.persistence.js";
 
 type CircuitDeviceRow = typeof circuitDeviceRows.$inferSelect;
 
@@ -129,6 +130,25 @@ export class ProjectDeviceRowSyncProjectCommandRepository
         );
       }
     }
+    const affectedCircuitIds = new Set(
+      input.command.payload.rows
+        .filter(
+          (assignment) =>
+            assignment.expected.phaseType !==
+            assignment.target.phaseType
+        )
+        .map(
+          (assignment) =>
+            persistedById.get(assignment.rowId)!.circuitId
+        )
+    );
+    for (const circuitId of affectedCircuitIds) {
+      updateDerivedCircuitVoltage(
+        tx,
+        input.projectId,
+        circuitId
+      );
+    }
 
     return inverse;
   }

src/db/repositories/project-device-structure-project-command.repository.ts

@@ -28,6 +28,7 @@ import { projectDevices } from "../schema/project-devices.js";
 import { projects } from "../schema/projects.js";
 import { toCircuitDeviceRowSnapshot } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { resolveProjectDeviceVoltage } from "./project-voltage.persistence.js";
 
 const circuitDeviceRowSnapshotFields = [
   "id",
@@ -125,6 +126,19 @@ export class ProjectDeviceStructureProjectCommandRepository
     if (!project) {
       throw new Error("Project does not exist.");
     }
+    if (
+      source === "user" &&
+      snapshot.voltageV !==
+        resolveProjectDeviceVoltage(
+          database,
+          projectId,
+          snapshot.phaseType
+        )
+    ) {
+      throw new Error(
+        "Project-device voltage must match the project phase voltage."
+      );
+    }
     const existing = database
       .select({ id: projectDevices.id })
       .from(projectDevices)

src/db/repositories/project-settings-project-command.repository.ts

@@ -15,6 +15,7 @@ import type { AppDatabase } from "../database-context.js";
 import { projects } from "../schema/projects.js";
 import { distributionBoards } from "../schema/distribution-boards.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { updateAllDerivedProjectVoltages } from "./project-voltage.persistence.js";
 
 export class ProjectSettingsProjectCommandRepository
   implements ProjectSettingsProjectCommandStore
@@ -94,6 +95,7 @@ export class ProjectSettingsProjectCommandRepository
     if (updated.changes !== 1) {
       throw new Error("Project changed before settings update.");
     }
+    updateAllDerivedProjectVoltages(tx, input.projectId);
 
     return inverse;
   }

src/db/repositories/project-snapshot.repository.ts

@@ -9,6 +9,7 @@ import {
   legacyProjectStateSnapshotSchemaVersion,
   previousProjectStateSnapshotSchemaVersion,
   projectStateSnapshotSchemaVersion,
+  supplyTypesProjectStateSnapshotSchemaVersion,
 } from "../../domain/models/project-state-snapshot.model.js";
 import type {
   CreateNamedProjectSnapshotInput,
@@ -146,6 +147,8 @@ export class ProjectSnapshotRepository implements ProjectSnapshotStore {
       stored.schemaVersion !== previousProjectStateSnapshotSchemaVersion &&
       stored.schemaVersion !==
         distributionBoardProjectStateSnapshotSchemaVersion &&
+      stored.schemaVersion !==
+        supplyTypesProjectStateSnapshotSchemaVersion &&
       stored.schemaVersion !== projectStateSnapshotSchemaVersion
     ) {
       throw new Error("Project snapshot schema version is not supported.");

src/db/repositories/project-voltage.persistence.ts

@@ -0,0 +1,154 @@
+import { and, eq } from "drizzle-orm";
+import {
+  resolveCircuitPhaseType,
+  resolveProjectVoltage,
+  type ElectricalPhaseType,
+  type ProjectVoltageSettings,
+} from "../../domain/services/project-voltage.service.js";
+import type { AppDatabase } from "../database-context.js";
+import { circuitDeviceRows } from "../schema/circuit-device-rows.js";
+import { circuitLists } from "../schema/circuit-lists.js";
+import { circuitSections } from "../schema/circuit-sections.js";
+import { circuits } from "../schema/circuits.js";
+import { projectDevices } from "../schema/project-devices.js";
+import { projects } from "../schema/projects.js";
+
+export function readProjectVoltageSettings(
+  database: AppDatabase,
+  projectId: string
+): ProjectVoltageSettings {
+  const project = database
+    .select({
+      singlePhaseVoltageV: projects.singlePhaseVoltageV,
+      threePhaseVoltageV: projects.threePhaseVoltageV,
+    })
+    .from(projects)
+    .where(eq(projects.id, projectId))
+    .get();
+  if (!project) {
+    throw new Error("Project not found.");
+  }
+  return project;
+}
+
+export function resolveProjectDeviceVoltage(
+  database: AppDatabase,
+  projectId: string,
+  phaseType: ElectricalPhaseType
+) {
+  return resolveProjectVoltage(
+    phaseType,
+    readProjectVoltageSettings(database, projectId)
+  );
+}
+
+export function resolveCircuitVoltage(
+  database: AppDatabase,
+  projectId: string,
+  sectionId: string,
+  devicePhaseTypes: ReadonlyArray<string | null | undefined> = []
+) {
+  const section = database
+    .select({ key: circuitSections.key })
+    .from(circuitSections)
+    .innerJoin(
+      circuitLists,
+      eq(circuitLists.id, circuitSections.circuitListId)
+    )
+    .where(
+      and(
+        eq(circuitSections.id, sectionId),
+        eq(circuitLists.projectId, projectId)
+      )
+    )
+    .get();
+  if (!section) {
+    throw new Error("Circuit section does not belong to project.");
+  }
+  return resolveProjectVoltage(
+    resolveCircuitPhaseType(section.key, devicePhaseTypes),
+    readProjectVoltageSettings(database, projectId)
+  );
+}
+
+export function updateDerivedCircuitVoltage(
+  database: AppDatabase,
+  projectId: string,
+  circuitId: string
+) {
+  const circuit = database
+    .select({
+      id: circuits.id,
+      sectionId: circuits.sectionId,
+    })
+    .from(circuits)
+    .innerJoin(circuitLists, eq(circuitLists.id, circuits.circuitListId))
+    .where(
+      and(
+        eq(circuits.id, circuitId),
+        eq(circuitLists.projectId, projectId)
+      )
+    )
+    .get();
+  if (!circuit) {
+    throw new Error("Circuit does not belong to project.");
+  }
+  const devicePhaseTypes = database
+    .select({ phaseType: circuitDeviceRows.phaseType })
+    .from(circuitDeviceRows)
+    .where(eq(circuitDeviceRows.circuitId, circuitId))
+    .all()
+    .map((row) => row.phaseType);
+  const voltage = resolveCircuitVoltage(
+    database,
+    projectId,
+    circuit.sectionId,
+    devicePhaseTypes
+  );
+  database
+    .update(circuits)
+    .set({ voltage })
+    .where(eq(circuits.id, circuitId))
+    .run();
+  return voltage;
+}
+
+export function updateAllDerivedProjectVoltages(
+  database: AppDatabase,
+  projectId: string
+) {
+  const settings = readProjectVoltageSettings(database, projectId);
+  const devices = database
+    .select({
+      id: projectDevices.id,
+      phaseType: projectDevices.phaseType,
+    })
+    .from(projectDevices)
+    .where(eq(projectDevices.projectId, projectId))
+    .all();
+  for (const device of devices) {
+    if (
+      device.phaseType !== "single_phase" &&
+      device.phaseType !== "three_phase"
+    ) {
+      throw new Error("Persisted project-device phase type is invalid.");
+    }
+    database
+      .update(projectDevices)
+      .set({
+        voltageV: resolveProjectVoltage(device.phaseType, settings),
+      })
+      .where(eq(projectDevices.id, device.id))
+      .run();
+  }
+
+  const projectCircuits = database
+    .select({ id: circuits.id })
+    .from(circuits)
+    .innerJoin(circuitLists, eq(circuitLists.id, circuits.circuitListId))
+    .where(eq(circuitLists.projectId, projectId))
+    .all();
+  for (const circuit of projectCircuits) {
+    updateDerivedCircuitVoltage(database, projectId, circuit.id);
+  }
+}

src/domain/models/circuit-tree.model.ts

@@ -58,6 +58,8 @@ export interface CircuitTreeSectionBlock {
 export interface CircuitTreeResponse {
   circuitListId: string;
   currentRevision: number;
+  singlePhaseVoltageV: number;
+  threePhaseVoltageV: number;
   sections: CircuitTreeSectionBlock[];
 }
 

src/domain/models/project-state-snapshot.model.ts

@@ -3,11 +3,16 @@ import {
   defaultDistributionBoardSupplyTypes,
   distributionBoardSupplyTypes,
 } from "../../shared/constants/distribution-board.js";
+import {
+  resolveCircuitPhaseType,
+  resolveProjectVoltage,
+} from "../services/project-voltage.service.js";
 
 export const legacyProjectStateSnapshotSchemaVersion = 1 as const;
 export const previousProjectStateSnapshotSchemaVersion = 2 as const;
 export const distributionBoardProjectStateSnapshotSchemaVersion = 3 as const;
-export const projectStateSnapshotSchemaVersion = 4 as const;
+export const supplyTypesProjectStateSnapshotSchemaVersion = 4 as const;
+export const projectStateSnapshotSchemaVersion = 5 as const;
 
 const idSchema = z.string().trim().min(1);
 const nullableStringSchema = z.string().nullable();
@@ -198,15 +203,20 @@ const distributionBoardProjectStateSnapshotSchema = z
   })
   .strict();
 
-export const projectStateSnapshotSchema = z
+const supplyTypesProjectStateSnapshotSchema = z
   .object({
-    schemaVersion: z.literal(projectStateSnapshotSchemaVersion),
+    schemaVersion: z.literal(supplyTypesProjectStateSnapshotSchemaVersion),
     project: currentProjectSchema,
     distributionBoards: z.array(distributionBoardSchema),
     ...commonProjectStateSnapshotContents,
   })
   .strict();
 
+export const projectStateSnapshotSchema =
+  supplyTypesProjectStateSnapshotSchema.extend({
+    schemaVersion: z.literal(projectStateSnapshotSchemaVersion),
+  });
+
 export type ProjectStateSnapshot = z.infer<
   typeof projectStateSnapshotSchema
 >;
@@ -217,23 +227,33 @@ export function parseProjectStateSnapshot(
   const version = isPlainObject(value) ? value.schemaVersion : undefined;
   const snapshot =
     version === legacyProjectStateSnapshotSchemaVersion
-      ? upgradeDistributionBoardProjectStateSnapshot(
+      ? upgradeSupplyTypesProjectStateSnapshot(
+          upgradeDistributionBoardProjectStateSnapshot(
             upgradePreviousProjectStateSnapshot(
               upgradeLegacyProjectStateSnapshot(
                 legacyProjectStateSnapshotSchema.parse(value)
               )
             )
           )
+        )
       : version === previousProjectStateSnapshotSchemaVersion
-        ? upgradeDistributionBoardProjectStateSnapshot(
+        ? upgradeSupplyTypesProjectStateSnapshot(
+            upgradeDistributionBoardProjectStateSnapshot(
               upgradePreviousProjectStateSnapshot(
                 previousProjectStateSnapshotSchema.parse(value)
               )
             )
+          )
         : version === distributionBoardProjectStateSnapshotSchemaVersion
-          ? upgradeDistributionBoardProjectStateSnapshot(
+          ? upgradeSupplyTypesProjectStateSnapshot(
+              upgradeDistributionBoardProjectStateSnapshot(
                 distributionBoardProjectStateSnapshotSchema.parse(value)
               )
+            )
+          : version === supplyTypesProjectStateSnapshotSchemaVersion
+            ? upgradeSupplyTypesProjectStateSnapshot(
+                supplyTypesProjectStateSnapshotSchema.parse(value)
+              )
           : projectStateSnapshotSchema.parse(value);
   assertProjectStateSnapshotRelations(snapshot);
   return snapshot;
@@ -271,10 +291,10 @@ function upgradePreviousProjectStateSnapshot(
 
 function upgradeDistributionBoardProjectStateSnapshot(
   snapshot: z.infer<typeof distributionBoardProjectStateSnapshotSchema>
-): ProjectStateSnapshot {
+): z.infer<typeof supplyTypesProjectStateSnapshotSchema> {
   return {
     ...snapshot,
-    schemaVersion: projectStateSnapshotSchemaVersion,
+    schemaVersion: supplyTypesProjectStateSnapshotSchemaVersion,
     project: {
       ...snapshot.project,
       enabledDistributionBoardSupplyTypes: [
@@ -284,6 +304,37 @@ function upgradeDistributionBoardProjectStateSnapshot(
   };
 }
 
+function upgradeSupplyTypesProjectStateSnapshot(
+  snapshot: z.infer<typeof supplyTypesProjectStateSnapshotSchema>
+): ProjectStateSnapshot {
+  const settings = snapshot.project;
+  const sectionById = new Map(
+    snapshot.circuitSections.map((section) => [section.id, section])
+  );
+  return {
+    ...snapshot,
+    schemaVersion: projectStateSnapshotSchemaVersion,
+    projectDevices: snapshot.projectDevices.map((device) => ({
+      ...device,
+      voltageV: resolveProjectVoltage(device.phaseType, settings),
+    })),
+    circuits: snapshot.circuits.map((circuit) => {
+      const section = sectionById.get(circuit.sectionId);
+      if (!section) {
+        return circuit;
+      }
+      const phaseType = resolveCircuitPhaseType(
+        section.key,
+        circuit.deviceRows.map((row) => row.phaseType)
+      );
+      return {
+        ...circuit,
+        voltage: resolveProjectVoltage(phaseType, settings),
+      };
+    }),
+  };
+}
+
 function isPlainObject(value: unknown): value is Record<string, unknown> {
   return value !== null && typeof value === "object" && !Array.isArray(value);
 }
@@ -364,6 +415,14 @@ function assertProjectStateSnapshotRelations(
   }
   for (const device of snapshot.projectDevices) {
     assertProjectOwnership(device.projectId, projectId, "project device");
+    if (
+      device.voltageV !==
+      resolveProjectVoltage(device.phaseType, snapshot.project)
+    ) {
+      throw new Error(
+        "Snapshot project device voltage must match project settings."
+      );
+    }
   }
   for (const floor of snapshot.floors) {
     assertProjectOwnership(floor.projectId, projectId, "floor");
@@ -394,6 +453,18 @@ function assertProjectStateSnapshotRelations(
         "Snapshot circuit reserve state must match its device rows."
       );
     }
+    const expectedVoltage = resolveProjectVoltage(
+      resolveCircuitPhaseType(
+        section.key,
+        circuit.deviceRows.map((row) => row.phaseType)
+      ),
+      snapshot.project
+    );
+    if (circuit.voltage !== expectedVoltage) {
+      throw new Error(
+        "Snapshot circuit voltage must match project settings."
+      );
+    }
     for (const row of circuit.deviceRows) {
       if (row.circuitId !== circuit.id) {
         throw new Error(

src/domain/services/project-voltage.service.ts

@@ -0,0 +1,35 @@
+export type ElectricalPhaseType = "single_phase" | "three_phase";
+
+export interface ProjectVoltageSettings {
+  singlePhaseVoltageV: number;
+  threePhaseVoltageV: number;
+}
+
+export function resolveProjectVoltage(
+  phaseType: ElectricalPhaseType,
+  settings: ProjectVoltageSettings
+) {
+  return phaseType === "three_phase"
+    ? settings.threePhaseVoltageV
+    : settings.singlePhaseVoltageV;
+}
+
+export function resolveCircuitPhaseType(
+  sectionKey: string,
+  devicePhaseTypes: ReadonlyArray<string | null | undefined> = []
+): ElectricalPhaseType {
+  if (sectionKey === "three_phase") {
+    return "three_phase";
+  }
+  if (sectionKey === "lighting" || sectionKey === "single_phase") {
+    return "single_phase";
+  }
+  const assignedPhaseTypes = devicePhaseTypes.filter(
+    (phaseType): phaseType is ElectricalPhaseType =>
+      phaseType === "single_phase" || phaseType === "three_phase"
+  );
+  return assignedPhaseTypes.length > 0 &&
+    assignedPhaseTypes.every((phaseType) => phaseType === "three_phase")
+    ? "three_phase"
+    : "single_phase";
+}

src/frontend/components/circuit-tree-editor.tsx

@@ -5,6 +5,10 @@ import {
   inferProjectDeviceSectionKey,
   isProjectDevicePlacementValid,
 } from "../../domain/services/project-device-placement.service";
+import {
+  resolveCircuitPhaseType,
+  resolveProjectVoltage,
+} from "../../domain/services/project-voltage.service";
 import {
   getInsertionSortOrder,
   resolveGridInsertionIntent,
@@ -819,6 +823,19 @@ export function CircuitTreeEditor(props: { projectId: string; circuitListId: str
     values: CreateCircuitInputDto,
     deviceRowValues: CreateCircuitDeviceRowInputDto[] = []
   ) {
+    const section = data?.sections.find(
+      (entry) => entry.id === values.sectionId
+    );
+    if (!section || !data) {
+      throw new Error("Bereich wurde nicht gefunden.");
+    }
+    const voltage = resolveProjectVoltage(
+      resolveCircuitPhaseType(
+        section.key,
+        deviceRowValues.map((row) => row.phaseType)
+      ),
+      data
+    );
     const circuitId = crypto.randomUUID();
     const deviceRows = deviceRowValues.map((row, index) =>
       createDeviceRowSnapshot(circuitId, row, (index + 1) * 10)
@@ -826,7 +843,7 @@ export function CircuitTreeEditor(props: { projectId: string; circuitListId: str
     return buildCircuitInsertSnapshot({
       id: circuitId,
       circuitListId,
-      values,
+      values: { ...values, voltage },
       deviceRows,
     });
   }

src/frontend/components/project-device-modal.tsx

@@ -47,7 +47,6 @@ export function ProjectDeviceModal({
       simultaneityFactor: Number(values.simultaneityFactor),
       cosPhi: optionalNumber(values.cosPhi),
       remark: optionalString(values.remark),
-      voltageV: optionalNumber(values.voltageV),
     });
   }
 
@@ -182,13 +181,6 @@ export function ProjectDeviceModal({
           step="0.01"
           value={values.cosPhi}
         />
-        <NumberField
-          id="device-voltage"
-          label="Spannung [V]"
-          min="1"
-          onChange={(value) => update("voltageV", value)}
-          value={values.voltageV}
-        />
         <div className="col-12">
           <label className="form-label" htmlFor="device-remark">
             Bemerkung
@@ -272,7 +264,6 @@ function toFormValues(device?: ProjectDeviceDto) {
     simultaneityFactor: String(device?.simultaneityFactor ?? 1),
     cosPhi: String(device?.cosPhi ?? 1),
     remark: device?.remark ?? "",
-    voltageV: String(device?.voltageV ?? ""),
   };
 }
 

src/frontend/types.ts

@@ -187,7 +187,6 @@ export interface CreateGlobalDeviceInput {
   quantity: number;
   installedPowerPerUnitKw: number;
   demandFactor: number;
-  voltageV?: number;
   phaseCount?: 1 | 3;
   powerFactor?: number;
   note?: string;
@@ -205,7 +204,6 @@ export interface CreateProjectDeviceInput {
   simultaneityFactor: number;
   cosPhi?: number;
   remark?: string;
-  voltageV?: number;
 }
 
 export interface ProjectDeviceSyncDifferenceDto {
@@ -314,6 +312,8 @@ export interface CircuitTreeMigrationReportDto {
 export interface CircuitTreeResponseDto {
   circuitListId: string;
   currentRevision: number;
+  singlePhaseVoltageV: number;
+  threePhaseVoltageV: number;
   sections: CircuitTreeSectionDto[];
   migrationReport?: CircuitTreeMigrationReportDto;
 }

src/frontend/utils/circuit-grid-model.ts

@@ -161,7 +161,6 @@ const circuitFieldKeys = new Set<CellKey>([
   "cableSummary",
   "rcdAssignment",
   "terminalDesignation",
-  "voltage",
   "controlRequirement",
   "status",
   "isReserve",
@@ -393,6 +392,7 @@ export function compareSortValues(left: GridValue, right: GridValue): number {
 
 export function getCellKind(rowType: RowType, key: CellKey): CellKind {
   if (key === "rowTotalPower" || key === "circuitTotalPower") return "computed";
+  if (key === "voltage") return "readonly";
   if (rowType === "section") return "readonly";
   if (rowType === "placeholder") {
     if (deviceFieldKeys.has(key)) return "deviceField";

src/frontend/utils/circuit-grid-projection.ts

@@ -149,6 +149,8 @@ function makeVisibleGridRow(
       value = circuit.circuitTotalPower;
     } else if (column.key === "circuitTotalPower" && circuit) {
       value = circuit.circuitTotalPower;
+    } else if (column.key === "voltage" && circuit) {
+      value = circuit.voltage;
     }
 
     return { cellKey: column.key, editable, kind, value };

src/server/controllers/circuit-tree.controller.ts

@@ -55,6 +55,8 @@ export async function getCircuitTree(req: Request, res: Response) {
     const tree: CircuitTreeResponse = {
       circuitListId,
       currentRevision: project.currentRevision,
+      singlePhaseVoltageV: project.singlePhaseVoltageV,
+      threePhaseVoltageV: project.threePhaseVoltageV,
       sections: sections.map((section) => ({
         id: section.id,
         key: section.key,
@@ -127,6 +129,8 @@ export async function getCircuitTree(req: Request, res: Response) {
       return res.json({
         circuitListId,
         currentRevision: project.currentRevision,
+        singlePhaseVoltageV: project.singlePhaseVoltageV,
+        threePhaseVoltageV: project.threePhaseVoltageV,
         sections: [],
         warning:
           "Circuit-first tables are not available yet. Run database migrations (including 0008_circuit_first_model).",

src/server/controllers/global-device.controller.ts

@@ -70,7 +70,6 @@ export async function copyProjectDeviceToGlobal(req: Request, res: Response) {
     quantity: source.quantity,
     installedPowerPerUnitKw: source.powerPerUnit,
     demandFactor: source.simultaneityFactor,
-    voltageV: source.voltageV ?? undefined,
     phaseCount: source.phaseType === "three_phase" ? 3 : 1,
     powerFactor: source.cosPhi ?? undefined,
     note: source.remark ?? undefined,

src/server/controllers/project-device.controller.ts

@@ -11,6 +11,7 @@ import { projectCommandService } from "../composition/project-command-stores.js"
 import {
   globalDeviceRepository,
   projectDeviceRepository,
+  projectRepository,
 } from "../composition/application-repositories.js";
 import {
   createProjectDeviceCommandSchema,
@@ -21,6 +22,7 @@ import {
 } from "../../shared/validation/project-device.schemas.js";
 import type { CreateProjectDeviceInput } from "../../shared/validation/project-device.schemas.js";
 import { respondWithProjectCommandError } from "./project-command.controller.js";
+import { resolveProjectVoltage } from "../../domain/services/project-voltage.service.js";
 
 export async function listProjectDevicesByProject(req: Request, res: Response) {
   const { projectId } = req.params;
@@ -41,9 +43,18 @@ export async function createProjectDevice(req: Request, res: Response) {
     return res.status(400).json({ error: parsed.error.flatten() });
   }
   const { expectedRevision, ...input } = parsed.data;
-  const projectDevice = toProjectDeviceSnapshot(projectId, randomUUID(), input);
 
   try {
+    const project = await projectRepository.findById(projectId);
+    if (!project) {
+      return res.status(404).json({ error: "Project not found" });
+    }
+    const projectDevice = toProjectDeviceSnapshot(
+      projectId,
+      randomUUID(),
+      input,
+      project
+    );
     const result = projectCommandService.executeUser({
       projectId,
       expectedRevision,
@@ -73,13 +84,17 @@ export async function updateProjectDevice(req: Request, res: Response) {
   const { expectedRevision, ...input } = parsed.data;
 
   try {
+    const project = await projectRepository.findById(projectId);
+    if (!project) {
+      return res.status(404).json({ error: "Project not found" });
+    }
     const result = projectCommandService.executeUser({
       projectId,
       expectedRevision,
       description: "Projektgerät bearbeiten",
       command: createProjectDeviceUpdateProjectCommand(
         projectDeviceId,
-        toProjectDeviceValues(input)
+        toProjectDeviceValues(input, project)
       ),
     });
     // Linked rows are synchronized only through the explicit review flow.
@@ -133,6 +148,10 @@ export async function copyGlobalDeviceToProject(req: Request, res: Response) {
   if (!source) {
     return res.status(404).json({ error: "Global device not found" });
   }
+  const project = await projectRepository.findById(projectId);
+  if (!project) {
+    return res.status(404).json({ error: "Project not found" });
+  }
 
   const projectDevice = toProjectDeviceSnapshot(projectId, randomUUID(), {
     name: source.name,
@@ -144,8 +163,7 @@ export async function copyGlobalDeviceToProject(req: Request, res: Response) {
     simultaneityFactor: source.demandFactor,
     cosPhi: source.powerFactor ?? undefined,
     remark: source.note ?? undefined,
-    voltageV: source.voltageV ?? undefined,
+  }, project);
-  });
 
   try {
     const result = projectCommandService.executeUser({
@@ -167,16 +185,26 @@ export async function copyGlobalDeviceToProject(req: Request, res: Response) {
 function toProjectDeviceSnapshot(
   projectId: string,
   id: string,
-  input: CreateProjectDeviceInput
+  input: CreateProjectDeviceInput,
+  project: {
+    singlePhaseVoltageV: number;
+    threePhaseVoltageV: number;
+  }
 ): ProjectDeviceSnapshot {
   return {
     id,
     projectId,
-    ...toProjectDeviceValues(input),
+    ...toProjectDeviceValues(input, project),
   };
 }
 
-function toProjectDeviceValues(input: CreateProjectDeviceInput) {
+function toProjectDeviceValues(
+  input: CreateProjectDeviceInput,
+  project: {
+    singlePhaseVoltageV: number;
+    threePhaseVoltageV: number;
+  }
+) {
   return {
     name: input.name,
     displayName: input.displayName,
@@ -189,7 +217,7 @@ function toProjectDeviceValues(input: CreateProjectDeviceInput) {
     simultaneityFactor: input.simultaneityFactor,
     cosPhi: input.cosPhi ?? null,
     remark: input.remark ?? null,
-    voltageV: input.voltageV ?? null,
+    voltageV: resolveProjectVoltage(input.phaseType, project),
   };
 }
 

src/shared/validation/global-device.schemas.ts

@@ -7,11 +7,10 @@ export const createGlobalDeviceSchema = z.object({
   quantity: z.number().min(0),
   installedPowerPerUnitKw: z.number().min(0),
   demandFactor: z.number().min(0).max(1),
-  voltageV: z.number().positive().optional(),
   phaseCount: z.union([z.literal(1), z.literal(3)]).optional(),
   powerFactor: z.number().min(0).max(1).optional(),
   note: z.string().optional(),
-});
+}).strict();
 
 export const updateGlobalDeviceSchema = createGlobalDeviceSchema;
 

src/shared/validation/project-device.schemas.ts

@@ -14,9 +14,7 @@ export const createProjectDeviceSchema = z.object({
   simultaneityFactor: z.number().min(0).max(1),
   cosPhi: z.number().min(0).max(1).optional(),
   remark: z.string().optional(),
-  // Transitional metadata used when importing from the legacy global-device library.
+}).strict();
-  voltageV: z.number().positive().optional(),
-});
 
 export const updateProjectDeviceSchema = createProjectDeviceSchema;
 

tests/circuit-power-calculation.test.ts

@@ -4,6 +4,10 @@ import {
   calculateCircuitTotalPower,
   calculateRowTotalPower,
 } from "../src/domain/calculations/circuit-power-calculation.js";
+import {
+  resolveCircuitPhaseType,
+  resolveProjectVoltage,
+} from "../src/domain/services/project-voltage.service.js";
 
 describe("circuit power calculation", () => {
   it("calculates row and circuit totals from device rows", () => {
@@ -16,3 +20,28 @@ describe("circuit power calculation", () => {
   });
 });
 
+describe("project voltage derivation", () => {
+  const settings = {
+    singlePhaseVoltageV: 240,
+    threePhaseVoltageV: 415,
+  };
+
+  it("derives device voltage exclusively from phase and project settings", () => {
+    assert.equal(resolveProjectVoltage("single_phase", settings), 240);
+    assert.equal(resolveProjectVoltage("three_phase", settings), 415);
+  });
+
+  it("uses section phase and handles unassigned circuits conservatively", () => {
+    assert.equal(resolveCircuitPhaseType("lighting", ["three_phase"]), "single_phase");
+    assert.equal(resolveCircuitPhaseType("single_phase", ["three_phase"]), "single_phase");
+    assert.equal(resolveCircuitPhaseType("three_phase", ["single_phase"]), "three_phase");
+    assert.equal(resolveCircuitPhaseType("unassigned", ["three_phase"]), "three_phase");
+    assert.equal(
+      resolveCircuitPhaseType("unassigned", ["three_phase", "single_phase"]),
+      "single_phase"
+    );
+    assert.equal(resolveCircuitPhaseType("unassigned", []), "single_phase");
+    assert.equal(resolveCircuitPhaseType("unassigned", [null]), "single_phase");
+  });
+});
+

tests/circuit-project-command.repository.test.ts

@@ -129,7 +129,7 @@ describe("circuit project-command repository", () => {
       const circuit = getCircuit(fixture.context);
       assert.equal(circuit.displayName, null);
       assert.equal(circuit.protectionRatedCurrent, 16);
-      assert.equal(circuit.voltage, 400);
+      assert.equal(circuit.voltage, 230);
       assert.equal(circuit.controlRequirement, "DALI");
       assert.equal(circuit.isReserve, 1);
       assert.equal(executed.revision.revisionNumber, 1);
@@ -138,7 +138,6 @@ describe("circuit project-command repository", () => {
         changes: [
           { field: "displayName", value: "Licht Bestand" },
           { field: "protectionRatedCurrent", value: 10 },
-          { field: "voltage", value: 230 },
           { field: "controlRequirement", value: "none" },
           { field: "isReserve", value: false },
         ],
@@ -149,7 +148,15 @@ describe("circuit project-command repository", () => {
         .from(projectChangeSets)
         .get();
       assert.ok(changeSet);
-      assert.deepEqual(deserializeProjectCommand(changeSet.forwardPayloadJson), command);
+      assert.deepEqual(
+        deserializeProjectCommand(changeSet.forwardPayloadJson),
+        createCircuitUpdateProjectCommand("circuit-1", {
+          displayName: null,
+          protectionRatedCurrent: 16,
+          controlRequirement: "DALI",
+          isReserve: true,
+        })
+      );
       assert.deepEqual(
         deserializeProjectCommand(changeSet.inversePayloadJson),
         executed.inverse

tests/project-device-schema.test.ts

@@ -41,6 +41,20 @@ describe("project device circuit-first schema", () => {
     assert.equal(result.success, false);
   });
 
+  it("rejects manually supplied device voltages", () => {
+    const result = createProjectDeviceSchema.safeParse({
+      name: "Pumpe",
+      displayName: "Pumpe",
+      phaseType: "three_phase",
+      quantity: 1,
+      powerPerUnit: 2,
+      simultaneityFactor: 1,
+      voltageV: 500,
+    });
+
+    assert.equal(result.success, false);
+  });
+
   it("requires a project revision for create and update commands", () => {
     const device = {
       name: "E-Line Pro",

tests/project-settings-project-command.repository.test.ts

@@ -12,6 +12,11 @@ import { ProjectSettingsProjectCommandRepository } from "../src/db/repositories/
 import { projectRevisions } from "../src/db/schema/project-revisions.js";
 import { projects } from "../src/db/schema/projects.js";
 import { distributionBoards } from "../src/db/schema/distribution-boards.js";
+import { circuitLists } from "../src/db/schema/circuit-lists.js";
+import { circuitSections } from "../src/db/schema/circuit-sections.js";
+import { circuits } from "../src/db/schema/circuits.js";
+import { projectDevices } from "../src/db/schema/project-devices.js";
+import { DistributionBoardFixtureRepository } from "./support/distribution-board-fixture.js";
 import { ProjectRevisionConflictError } from "../src/domain/errors/project-revision-conflict.error.js";
 import { createProjectSettingsUpdateProjectCommand } from "../src/domain/models/project-settings-project-command.model.js";
 import { updateProjectSettings } from "../src/frontend/utils/api.js";
@@ -78,6 +83,86 @@ function settings(
   };
 }
 
+function seedDerivedVoltageRecords(context: DatabaseContext) {
+  context.db.insert(projectDevices).values([
+    {
+      id: "device-single",
+      projectId: "project-1",
+      name: "Leuchte",
+      displayName: "Leuchte",
+      phaseType: "single_phase",
+      quantity: 1,
+      powerPerUnit: 0.1,
+      simultaneityFactor: 1,
+      voltageV: 230,
+    },
+    {
+      id: "device-three",
+      projectId: "project-1",
+      name: "Pumpe",
+      displayName: "Pumpe",
+      phaseType: "three_phase",
+      quantity: 1,
+      powerPerUnit: 2,
+      simultaneityFactor: 1,
+      voltageV: 400,
+    },
+  ]).run();
+  const board = new DistributionBoardFixtureRepository(
+    context.db
+  ).createWithCircuitListAndDefaultSections("project-1", "UV-01");
+  const list = context.db
+    .select()
+    .from(circuitLists)
+    .where(eq(circuitLists.distributionBoardId, board.id))
+    .get();
+  assert.ok(list);
+  const sections = context.db
+    .select()
+    .from(circuitSections)
+    .where(eq(circuitSections.circuitListId, list.id))
+    .all();
+  const singleSection = sections.find((section) => section.key === "single_phase");
+  const threeSection = sections.find((section) => section.key === "three_phase");
+  assert.ok(singleSection);
+  assert.ok(threeSection);
+  context.db.insert(circuits).values([
+    {
+      id: "circuit-single",
+      circuitListId: list.id,
+      sectionId: singleSection.id,
+      equipmentIdentifier: "-2F1",
+      sortOrder: 10,
+      voltage: 230,
+      isReserve: 1,
+    },
+    {
+      id: "circuit-three",
+      circuitListId: list.id,
+      sectionId: threeSection.id,
+      equipmentIdentifier: "-3F1",
+      sortOrder: 10,
+      voltage: 400,
+      isReserve: 1,
+    },
+  ]).run();
+}
+
+function getDerivedVoltages(context: DatabaseContext) {
+  return {
+    devices: context.db
+      .select({ id: projectDevices.id, voltageV: projectDevices.voltageV })
+      .from(projectDevices)
+      .all()
+      .sort((left, right) => left.id.localeCompare(right.id)),
+    circuits: context.db
+      .select({ id: circuits.id, voltage: circuits.voltage })
+      .from(circuits)
+      .all()
+      .sort((left, right) => left.id.localeCompare(right.id)),
+  };
+}
+
 describe("project settings project-command repository", () => {
   it("validates settings commands and sends the expected revision from the frontend", async () => {
     assert.throws(
@@ -137,6 +222,7 @@ describe("project settings project-command repository", () => {
   it("updates both voltages and supports persisted undo and redo", () => {
     const context = createTestDatabase();
     try {
+      seedDerivedVoltageRecords(context);
       const repository = new ProjectSettingsProjectCommandRepository(
         context.db
       );
@@ -171,6 +257,16 @@ describe("project settings project-command repository", () => {
         }),
         currentRevision: 1,
       });
+      assert.deepEqual(getDerivedVoltages(context), {
+        devices: [
+          { id: "device-single", voltageV: 240 },
+          { id: "device-three", voltageV: 415 },
+        ],
+        circuits: [
+          { id: "circuit-single", voltage: 240 },
+          { id: "circuit-three", voltage: 415 },
+        ],
+      });
       assert.deepEqual(forward.inverse.payload, {
         name: "Testprojekt",
         internalProjectNumber: "INT-1",
@@ -216,6 +312,16 @@ describe("project settings project-command repository", () => {
         ],
         currentRevision: 2,
       });
+      assert.deepEqual(getDerivedVoltages(context), {
+        devices: [
+          { id: "device-single", voltageV: 230 },
+          { id: "device-three", voltageV: 400 },
+        ],
+        circuits: [
+          { id: "circuit-single", voltage: 230 },
+          { id: "circuit-three", voltage: 400 },
+        ],
+      });
 
       const redoStep = history.getNextCommand("project-1", "redo");
       assert.ok(redoStep);
@@ -244,6 +350,16 @@ describe("project settings project-command repository", () => {
         ],
         currentRevision: 3,
       });
+      assert.deepEqual(getDerivedVoltages(context), {
+        devices: [
+          { id: "device-single", voltageV: 240 },
+          { id: "device-three", voltageV: 415 },
+        ],
+        circuits: [
+          { id: "circuit-single", voltage: 240 },
+          { id: "circuit-three", voltage: 415 },
+        ],
+      });
     } finally {
       context.close();
     }

tests/project-state-restore-command.repository.test.ts

@@ -101,6 +101,7 @@ function createTestDatabase(): DatabaseContext {
       quantity: 1,
       powerPerUnit: 2.5,
       simultaneityFactor: 0.8,
+      voltageV: 400,
     })
     .run();
   context.db
@@ -112,6 +113,7 @@ function createTestDatabase(): DatabaseContext {
       equipmentIdentifier: "-1F1",
       displayName: "Ausgang",
       sortOrder: 10,
+      voltage: 230,
       isReserve: 0,
     })
     .run();
@@ -165,7 +167,10 @@ function changeCompleteProjectState(context: DatabaseContext) {
     .run();
   context.db
     .update(circuits)
-    .set({ displayName: "Geänderter Stromkreis" })
+    .set({
+      displayName: "Geänderter Stromkreis",
+      voltage: 240,
+    })
     .where(eq(circuits.id, "circuit-1"))
     .run();
   context.db
@@ -198,8 +203,14 @@ function changeCompleteProjectState(context: DatabaseContext) {
       quantity: 2,
       powerPerUnit: 0.05,
       simultaneityFactor: 1,
+      voltageV: 240,
     })
     .run();
+  context.db
+    .update(projectDevices)
+    .set({ voltageV: 415 })
+    .where(eq(projectDevices.id, "device-1"))
+    .run();
   new DistributionBoardFixtureRepository(
     context.db
   ).createWithCircuitListAndDefaultSections("project-1", "UV-02");

tests/project-state-snapshot.test.ts

@@ -128,6 +128,36 @@ describe("project state snapshot model", () => {
     ]);
   });
 
+  it("normalizes version-four device voltages to project settings", () => {
+    const previous = {
+      ...minimalSnapshot(),
+      schemaVersion: 4 as const,
+      projectDevices: [
+        {
+          id: "device-1",
+          projectId: "project-1",
+          name: "Pumpe",
+          displayName: "Pumpe",
+          phaseType: "three_phase" as const,
+          connectionKind: null,
+          costGroup: null,
+          category: null,
+          quantity: 1,
+          powerPerUnit: 2,
+          simultaneityFactor: 1,
+          cosPhi: null,
+          remark: null,
+          voltageV: 500,
+        },
+      ],
+    };
+
+    const snapshot = parseProjectStateSnapshot(previous);
+
+    assert.equal(snapshot.schemaVersion, projectStateSnapshotSchemaVersion);
+    assert.equal(snapshot.projectDevices[0]?.voltageV, 400);
+  });
+
   it("rejects duplicate ids and cross-project ownership", () => {
     assert.throws(
       () =>

tests/project-version-history.test.ts

@@ -156,11 +156,11 @@ describe("project device modal presentation", () => {
       "Anzahl",
       "Leistung je Stück [kW]",
       "Gleichzeitigkeitsfaktor",
-      "Spannung [V]",
       "Bemerkung",
     ]) {
       assert.match(markup, new RegExp(label.replace("[", "\\[").replace("]", "\\]")));
     }
+    assert.doesNotMatch(markup, /Spannung \[V\]/);
   });
 });