diff --git a/src/db/repositories/circuit-device-row-move-project-command.repository.ts b/src/db/repositories/circuit-device-row-move-project-command.repository.ts
index 2c5bfc9..e1e3f5a 100644
--- a/src/db/repositories/circuit-device-row-move-project-command.repository.ts
+++ b/src/db/repositories/circuit-device-row-move-project-command.repository.ts
@@ -23,6 +23,7 @@ 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";
+import { assertCircuitsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 
 interface PersistedMoveRow {
   id: string;
@@ -171,6 +172,9 @@ export class CircuitDeviceRowMoveProjectCommandRepository
       projectId,
       destinationCircuitIds
     );
+    assertCircuitsAreNotReferencedAsFeeders(database, projectId, [
+      targetCircuit.id,
+    ]);
     const deleted = database
       .delete(circuits)
       .where(
diff --git a/src/db/repositories/circuit-group-subtree-project-command.repository.ts b/src/db/repositories/circuit-group-subtree-project-command.repository.ts
index 448cf99..9bf27a0 100644
--- a/src/db/repositories/circuit-group-subtree-project-command.repository.ts
+++ b/src/db/repositories/circuit-group-subtree-project-command.repository.ts
@@ -26,6 +26,7 @@ import { distributionBoardComponentProtectionDevices } from "../schema/distribut
 import { distributionBoardComponents } from "../schema/distribution-board-components.js";
 import { toCircuitDeviceRowInsertValues } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { assertCircuitsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 
 export class CircuitGroupSubtreeProjectCommandRepository
   implements CircuitGroupSubtreeProjectCommandStore
@@ -65,6 +66,11 @@ export class CircuitGroupSubtreeProjectCommandRepository
           "Circuit-group subtree changed before deletion."
         );
       }
+      assertCircuitsAreNotReferencedAsFeeders(
+        database,
+        projectId,
+        current.circuits.map((entry) => entry.circuit.id)
+      );
       const deleted = database
         .delete(circuitSections)
         .where(eq(circuitSections.id, current.group.id))
diff --git a/src/db/repositories/circuit-structure-project-command.repository.ts b/src/db/repositories/circuit-structure-project-command.repository.ts
index 9b8941d..e7cfcb2 100644
--- a/src/db/repositories/circuit-structure-project-command.repository.ts
+++ b/src/db/repositories/circuit-structure-project-command.repository.ts
@@ -26,6 +26,7 @@ import {
   toCircuitDeviceRowSnapshot,
 } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { assertCircuitsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 import { resolveCircuitVoltage } from "./project-voltage.persistence.js";
 import { assertEquipmentIdentifierAvailable } from "./equipment-identifier-uniqueness.persistence.js";
 
@@ -236,6 +237,8 @@ export class CircuitStructureProjectCommandRepository
       protectionDevice: protectionDevice ?? null,
     });
 
+    assertCircuitsAreNotReferencedAsFeeders(database, projectId, [circuit.id]);
+
     const result = database
       .delete(circuits)
       .where(
diff --git a/src/db/repositories/distribution-board-feeding-deletion-guard.persistence.ts b/src/db/repositories/distribution-board-feeding-deletion-guard.persistence.ts
new file mode 100644
index 0000000..679f31e
--- /dev/null
+++ b/src/db/repositories/distribution-board-feeding-deletion-guard.persistence.ts
@@ -0,0 +1,65 @@
+import { and, asc, eq, inArray } from "drizzle-orm";
+import type { AppDatabase } from "../database-context.js";
+import { distributionBoards } from "../schema/distribution-boards.js";
+
+export function assertBoardsAreNotReferencedAsFeeders(
+  database: AppDatabase,
+  projectId: string,
+  distributionBoardIds: string[]
+) {
+  if (distributionBoardIds.length === 0) return;
+  const dependent = database
+    .select({
+      name: distributionBoards.name,
+      boardNumber: distributionBoards.boardNumber,
+    })
+    .from(distributionBoards)
+    .where(
+      and(
+        eq(distributionBoards.projectId, projectId),
+        inArray(
+          distributionBoards.feedingDistributionBoardId,
+          [...new Set(distributionBoardIds)]
+        )
+      )
+    )
+    .orderBy(asc(distributionBoards.boardNumber), asc(distributionBoards.name))
+    .limit(1)
+    .get();
+  if (dependent) throwFeedingReferenceError(dependent);
+}
+
+export function assertCircuitsAreNotReferencedAsFeeders(
+  database: AppDatabase,
+  projectId: string,
+  circuitIds: string[]
+) {
+  if (circuitIds.length === 0) return;
+  const dependent = database
+    .select({
+      name: distributionBoards.name,
+      boardNumber: distributionBoards.boardNumber,
+    })
+    .from(distributionBoards)
+    .where(
+      and(
+        eq(distributionBoards.projectId, projectId),
+        inArray(
+          distributionBoards.feedingCircuitId,
+          [...new Set(circuitIds)]
+        )
+      )
+    )
+    .orderBy(asc(distributionBoards.boardNumber), asc(distributionBoards.name))
+    .limit(1)
+    .get();
+  if (dependent) throwFeedingReferenceError(dependent);
+}
+
+function throwFeedingReferenceError(dependent: {
+  name: string;
+  boardNumber: string | null;
+}): never {
+  const label = dependent.boardNumber ?? dependent.name;
+  throw new Error(`Speist ${label} – erst Einspeisung ändern.`);
+}
diff --git a/src/db/repositories/distribution-board-structure-project-command.repository.ts b/src/db/repositories/distribution-board-structure-project-command.repository.ts
index a4fba2b..9346df7 100644
--- a/src/db/repositories/distribution-board-structure-project-command.repository.ts
+++ b/src/db/repositories/distribution-board-structure-project-command.repository.ts
@@ -30,6 +30,7 @@ import { distributionBoards } from "../schema/distribution-boards.js";
 import { floors } from "../schema/floors.js";
 import { projects } from "../schema/projects.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { assertBoardsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 
 export class DistributionBoardStructureProjectCommandRepository
   implements DistributionBoardStructureProjectCommandStore
@@ -248,6 +249,8 @@ export class DistributionBoardStructureProjectCommandRepository
       );
     }
 
+    assertBoardsAreNotReferencedAsFeeders(database, projectId, [board.id]);
+
     const deleted = database
       .delete(distributionBoards)
       .where(
diff --git a/src/db/repositories/distribution-board-subtree-project-command.repository.ts b/src/db/repositories/distribution-board-subtree-project-command.repository.ts
index 5d33b75..969c287 100644
--- a/src/db/repositories/distribution-board-subtree-project-command.repository.ts
+++ b/src/db/repositories/distribution-board-subtree-project-command.repository.ts
@@ -32,6 +32,7 @@ import { projects } from "../schema/projects.js";
 import { rooms } from "../schema/rooms.js";
 import { toCircuitDeviceRowInsertValues } from "./circuit-device-row-structure.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import { assertBoardsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 
 export class DistributionBoardSubtreeProjectCommandRepository
   implements DistributionBoardSubtreeProjectCommandStore
@@ -82,6 +83,9 @@ export class DistributionBoardSubtreeProjectCommandRepository
           "Distribution-board subtree changed before deletion."
         );
       }
+      assertBoardsAreNotReferencedAsFeeders(database, projectId, [
+        current.distributionBoard.id,
+      ]);
       const deleted = database
         .delete(distributionBoards)
         .where(
diff --git a/src/db/repositories/external-object-new-circuit-project-command.repository.ts b/src/db/repositories/external-object-new-circuit-project-command.repository.ts
index bea64ff..7667a28 100644
--- a/src/db/repositories/external-object-new-circuit-project-command.repository.ts
+++ b/src/db/repositories/external-object-new-circuit-project-command.repository.ts
@@ -33,6 +33,7 @@ import {
   snapshotsEqual,
 } from "./external-object-assignment.persistence.js";
 import { assertEquipmentIdentifierAvailable } from "./equipment-identifier-uniqueness.persistence.js";
+import { assertCircuitsAreNotReferencedAsFeeders } from "./distribution-board-feeding-deletion-guard.persistence.js";
 
 export class ExternalObjectNewCircuitProjectCommandRepository
   implements ExternalObjectNewCircuitProjectCommandStore
@@ -162,6 +163,9 @@ export class ExternalObjectNewCircuitProjectCommandRepository
       objects,
       "External object changed during new-circuit assignment."
     );
+    assertCircuitsAreNotReferencedAsFeeders(database, projectId, [
+      expectedCircuit.id,
+    ]);
     const deleted = database.delete(circuits).where(and(
       eq(circuits.id, expectedCircuit.id),
       eq(circuits.circuitListId, expectedCircuit.circuitListId)
diff --git a/tests/circuit-device-row-move-project-command.repository.test.ts b/tests/circuit-device-row-move-project-command.repository.test.ts
index 0569099..8975368 100644
--- a/tests/circuit-device-row-move-project-command.repository.test.ts
+++ b/tests/circuit-device-row-move-project-command.repository.test.ts
@@ -14,6 +14,7 @@ import { circuitDeviceRows } from "../src/db/schema/circuit-device-rows.js";
 import { circuitProtectionDevices } from "../src/db/schema/circuit-protection-devices.js";
 import { circuitSections } from "../src/db/schema/circuit-sections.js";
 import { circuits } from "../src/db/schema/circuits.js";
+import { distributionBoards } from "../src/db/schema/distribution-boards.js";
 import { projectRevisions } from "../src/db/schema/project-revisions.js";
 import { projects } from "../src/db/schema/projects.js";
 import {
@@ -611,6 +612,62 @@ describe("circuit device-row move project-command repository", () => {
     }
   });
 
+  it("blocks undo from removing a generated circuit used as a feeder", () => {
+    const fixture = createTestDatabase();
+    try {
+      const store = new CircuitDeviceRowMoveProjectCommandRepository(
+        fixture.context.db
+      );
+      const targetCircuit = createMoveTargetSnapshot(fixture);
+      const command = createCircuitDeviceRowMoveWithNewCircuitProjectCommand(
+        "create",
+        targetCircuit,
+        [{
+          rowId: "row-1",
+          expectedCircuitId: "circuit-1",
+          expectedSortOrder: 10,
+          targetCircuitId: targetCircuit.id,
+          targetSortOrder: 10,
+        }]
+      );
+      const moved = store.execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "user",
+        command,
+      });
+      const downstream = new DistributionBoardFixtureRepository(
+        fixture.context.db
+      ).createWithCircuitListAndDefaultSections("project-1", "UV-02");
+      fixture.context.db
+        .update(distributionBoards)
+        .set({
+          feedingDistributionBoardId: fixture.circuitListId,
+          feedingCircuitId: targetCircuit.id,
+        })
+        .where(eq(distributionBoards.id, downstream.id))
+        .run();
+
+      assert.throws(
+        () => store.execute({
+          projectId: "project-1",
+          expectedRevision: 1,
+          source: "undo",
+          historyTargetChangeSetId: moved.revision.changeSetId,
+          command: moved.inverse,
+        }),
+        /Speist UV-02 – erst Einspeisung ändern\./
+      );
+      assert.equal(getRow(fixture.context, "row-1")?.circuitId, targetCircuit.id);
+      assert.ok(
+        fixture.context.db.select().from(circuits)
+          .where(eq(circuits.id, targetCircuit.id)).get()
+      );
+    } finally {
+      fixture.context.close();
+    }
+  });
+
   it("rejects deletion when the created target changed outside history", () => {
     const fixture = createTestDatabase();
     try {
diff --git a/tests/circuit-group-subtree-project-command.repository.test.ts b/tests/circuit-group-subtree-project-command.repository.test.ts
index 05d7dcc..8494798 100644
--- a/tests/circuit-group-subtree-project-command.repository.test.ts
+++ b/tests/circuit-group-subtree-project-command.repository.test.ts
@@ -16,6 +16,7 @@ import { circuitSections } from "../src/db/schema/circuit-sections.js";
 import { circuits } from "../src/db/schema/circuits.js";
 import { distributionBoardComponentProtectionDevices } from "../src/db/schema/distribution-board-component-protection-devices.js";
 import { distributionBoardComponents } from "../src/db/schema/distribution-board-components.js";
+import { distributionBoards } from "../src/db/schema/distribution-boards.js";
 import { projectRevisions } from "../src/db/schema/project-revisions.js";
 import { projects } from "../src/db/schema/projects.js";
 import { createCircuitGroupDeleteSubtreeProjectCommand } from "../src/domain/models/circuit-group-subtree-project-command.model.js";
@@ -228,6 +229,45 @@ describe("circuit-group subtree project command", () => {
     }
   });
 
+  it("blocks deleting a group containing a feeding circuit", () => {
+    const context = createTestDatabase();
+    try {
+      const list = context.db.select().from(circuitLists).get()!;
+      const downstream = new DistributionBoardFixtureRepository(
+        context.db
+      ).createWithCircuitListAndDefaultSections("project-1", "Unterverteiler");
+      context.db
+        .update(distributionBoards)
+        .set({
+          feedingDistributionBoardId: list.distributionBoardId,
+          feedingCircuitId: "subtree-circuit",
+        })
+        .where(eq(distributionBoards.id, downstream.id))
+        .run();
+      const repository =
+        new CircuitGroupSubtreeProjectCommandRepository(context.db);
+      const groupId = context.db
+        .select()
+        .from(circuits)
+        .where(eq(circuits.id, "subtree-circuit"))
+        .get()!.sectionId;
+      const snapshot = repository.capture("project-1", groupId);
+
+      assert.throws(
+        () => repository.execute({
+          projectId: "project-1",
+          expectedRevision: 0,
+          source: "user",
+          command: createCircuitGroupDeleteSubtreeProjectCommand(snapshot),
+        }),
+        /Speist Unterverteiler – erst Einspeisung ändern\./
+      );
+      assert.deepEqual(repository.capture("project-1", groupId), snapshot);
+    } finally {
+      context.close();
+    }
+  });
+
   it("rolls back a cascaded deletion when history persistence fails", () => {
     const context = createTestDatabase();
     try {
diff --git a/tests/circuit-structure-project-command.repository.test.ts b/tests/circuit-structure-project-command.repository.test.ts
index 4c05554..8985ad0 100644
--- a/tests/circuit-structure-project-command.repository.test.ts
+++ b/tests/circuit-structure-project-command.repository.test.ts
@@ -14,6 +14,7 @@ import { circuitDeviceRows } from "../src/db/schema/circuit-device-rows.js";
 import { circuitProtectionDevices } from "../src/db/schema/circuit-protection-devices.js";
 import { circuitSections } from "../src/db/schema/circuit-sections.js";
 import { circuits } from "../src/db/schema/circuits.js";
+import { distributionBoards } from "../src/db/schema/distribution-boards.js";
 import { projectDevices } from "../src/db/schema/project-devices.js";
 import { projectRevisions } from "../src/db/schema/project-revisions.js";
 import { projects } from "../src/db/schema/projects.js";
@@ -442,6 +443,48 @@ describe("circuit structure project-command repository", () => {
     }
   });
 
+  it("blocks deleting a circuit that feeds a distribution board", () => {
+    const fixture = createTestDatabase();
+    try {
+      const downstream = new DistributionBoardFixtureRepository(
+        fixture.context.db
+      ).createWithCircuitListAndDefaultSections("project-1", "UV Unterverteiler");
+      fixture.context.db
+        .update(distributionBoards)
+        .set({
+          boardNumber: "UV-02",
+          feedingDistributionBoardId: fixture.circuitListId,
+          feedingCircuitId: "circuit-existing",
+        })
+        .where(eq(distributionBoards.id, downstream.id))
+        .run();
+
+      const store = new CircuitStructureProjectCommandRepository(
+        fixture.context.db
+      );
+      assert.throws(
+        () =>
+          store.execute({
+            projectId: "project-1",
+            expectedRevision: 0,
+            source: "user",
+            command: createCircuitDeleteProjectCommand(
+              "circuit-existing",
+              fixture.circuitListId
+            ),
+          }),
+        /Speist UV-02 – erst Einspeisung ändern\./
+      );
+      assert.ok(getCircuit(fixture.context, "circuit-existing"));
+      assert.equal(
+        fixture.context.db.select().from(projectRevisions).all().length,
+        0
+      );
+    } finally {
+      fixture.context.close();
+    }
+  });
+
   it("rolls back insert and delete for late history failures", () => {
     const fixture = createTestDatabase();
     try {
diff --git a/tests/distribution-board-structure-project-command.repository.test.ts b/tests/distribution-board-structure-project-command.repository.test.ts
index e6aff4b..a02f005 100644
--- a/tests/distribution-board-structure-project-command.repository.test.ts
+++ b/tests/distribution-board-structure-project-command.repository.test.ts
@@ -219,6 +219,54 @@ describe("distribution-board structure project command", () => {
     }
   });
 
+  it("blocks undo from removing an empty board used as a feeder", () => {
+    const context = createTestDatabase();
+    try {
+      const repository =
+        new DistributionBoardStructureProjectCommandRepository(context.db);
+      const upstream = createDistributionBoardStructureSnapshot(
+        "project-1",
+        "NSHV"
+      );
+      const inserted = repository.execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "user",
+        command: createDistributionBoardInsertProjectCommand(upstream),
+      });
+      const downstream = createDistributionBoardStructureSnapshot(
+        "project-1",
+        "UV-01"
+      );
+      context.db.insert(distributionBoards).values({
+        ...downstream.distributionBoard,
+        boardNumber: "UV-01",
+        feedingDistributionBoardId: upstream.distributionBoard.id,
+      }).run();
+      context.db.insert(circuitLists).values(downstream.circuitList).run();
+      context.db.insert(circuitSections).values(downstream.sections).run();
+      context.db.insert(distributionBoardComponents)
+        .values(downstream.components).run();
+
+      assert.throws(
+        () => repository.execute({
+          projectId: "project-1",
+          expectedRevision: 1,
+          source: "undo",
+          historyTargetChangeSetId: inserted.revision.changeSetId,
+          command: inserted.inverse,
+        }),
+        /Speist UV-01 – erst Einspeisung ändern\./
+      );
+      assert.ok(
+        context.db.select().from(distributionBoards)
+          .where(eq(distributionBoards.id, upstream.distributionBoard.id)).get()
+      );
+    } finally {
+      context.close();
+    }
+  });
+
   it("allows only supply types enabled in the project", () => {
     const context = createTestDatabase();
     try {
diff --git a/tests/distribution-board-subtree-project-command.repository.test.ts b/tests/distribution-board-subtree-project-command.repository.test.ts
index 7975f2b..6508b9b 100644
--- a/tests/distribution-board-subtree-project-command.repository.test.ts
+++ b/tests/distribution-board-subtree-project-command.repository.test.ts
@@ -291,6 +291,43 @@ describe("distribution-board subtree project command", () => {
     }
   });
 
+  it("blocks deleting a board subtree that feeds another board", () => {
+    const context = createTestDatabase();
+    try {
+      const upstream = createPopulatedBoard(context);
+      const downstream = new DistributionBoardFixtureRepository(
+        context.db
+      ).createWithCircuitListAndDefaultSections("project-1", "Unterverteiler");
+      context.db
+        .update(distributionBoards)
+        .set({
+          boardNumber: "UV-03",
+          feedingDistributionBoardId: upstream.id,
+        })
+        .where(eq(distributionBoards.id, downstream.id))
+        .run();
+      const repository =
+        new DistributionBoardSubtreeProjectCommandRepository(context.db);
+      const snapshot = repository.capture("project-1", upstream.id);
+
+      assert.throws(
+        () =>
+          repository.execute({
+            projectId: "project-1",
+            expectedRevision: 0,
+            source: "user",
+            command:
+              createDistributionBoardDeleteSubtreeProjectCommand(snapshot),
+          }),
+        /Speist UV-03 – erst Einspeisung ändern\./
+      );
+      assert.deepEqual(repository.capture("project-1", upstream.id), snapshot);
+      assert.equal(context.db.select().from(projectRevisions).all().length, 0);
+    } finally {
+      context.close();
+    }
+  });
+
   it("rolls back a cascaded deletion when history persistence fails", () => {
     const context = createTestDatabase();
     try {
diff --git a/tests/external-object-row-assignment-project-command.repository.test.ts b/tests/external-object-row-assignment-project-command.repository.test.ts
index da8551e..35579eb 100644
--- a/tests/external-object-row-assignment-project-command.repository.test.ts
+++ b/tests/external-object-row-assignment-project-command.repository.test.ts
@@ -533,6 +533,61 @@ describe("external object new-circuit project command", () => {
     }
   });
 
+  it("blocks history removal when the generated circuit became a feeder", () => {
+    const context = createFixture(null);
+    try {
+      const object = objectSnapshot(null);
+      const circuit = newExternalCircuit(context.db);
+      const command = createExternalObjectNewCircuitProjectCommand(
+        externalObjectAssignToNewCircuitCommandType,
+        {
+          circuit,
+          objects: [{
+            expected: object,
+            target: { ...object, circuitDeviceRowId: "row-new" },
+          }],
+          confirmedConflictObjectIds: [],
+        }
+      );
+      const repository = new ExternalObjectNewCircuitProjectCommandRepository(context.db);
+      const inserted = repository.execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "user",
+        command,
+      });
+      context.db.insert(distributionBoards).values({
+        id: "board-2",
+        projectId: "project-1",
+        name: "Unterverteiler",
+        boardNumber: "UV-02",
+        feedingDistributionBoardId: "board-1",
+        feedingCircuitId: circuit.id,
+      }).run();
+
+      assert.throws(
+        () => repository.execute({
+          projectId: "project-1",
+          expectedRevision: 1,
+          source: "undo",
+          historyTargetChangeSetId: inserted.revision.changeSetId,
+          command: inserted.inverse,
+        }),
+        /Speist UV-02 – erst Einspeisung ändern\./
+      );
+      assert.ok(
+        context.db.select().from(circuits)
+          .where(eq(circuits.id, circuit.id)).get()
+      );
+      assert.equal(
+        context.db.select().from(externalModelObjects).get()!.circuitDeviceRowId,
+        "row-new"
+      );
+    } finally {
+      context.close();
+    }
+  });
+
   it("rolls back the complete circuit subtree when history persistence fails", () => {
     const context = createFixture(null);
     try {