diff --git a/src/meshapi/models/install.py b/src/meshapi/models/install.py
index e50d6b62..b6f265e2 100644
--- a/src/meshapi/models/install.py
+++ b/src/meshapi/models/install.py
@@ -142,4 +142,11 @@ def save(self, *args: Any, **kwargs: Any) -> None:
             if self.install_number != original.install_number:
                 raise ValidationError("Install number is immutable")
 
+        if self._state.adding:
+            if not self.node:
+                if self.building.primary_node:
+                    self.node = self.building.primary_node
+                elif self.building.nodes:
+                    self.node = self.building.nodes.first()
+
         super().save(*args, **kwargs)
diff --git a/src/meshapi/tests/test_install.py b/src/meshapi/tests/test_install.py
index b79494f5..9178fefe 100644
--- a/src/meshapi/tests/test_install.py
+++ b/src/meshapi/tests/test_install.py
@@ -6,7 +6,7 @@
 from django.core.exceptions import ValidationError
 from django.test import TestCase
 
-from meshapi.models import Building, Install, Member
+from meshapi.models import Building, Install, Member, Node
 from meshapi.tests.sample_data import sample_building, sample_install, sample_member
 
 
@@ -43,6 +43,78 @@ def test_construct_install_no_id_yes_install_number(self):
         self.assertIsNotNone(install2.id)
         self.assertEqual(install2.install_number, 89)
 
+    def test_construct_install_building_has_node(self):
+        building_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0)
+        building_node.save()
+
+        self.building_1.primary_node = building_node
+        self.building_1.save()
+
+        install = Install(**self.sample_install_copy, install_number=45)
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, building_node)
+
+    def test_construct_install_building_has_node_without_primary(self):
+        building_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0)
+        building_node.save()
+
+        self.building_1.nodes.add(building_node)
+        self.building_1.save()
+
+        install = Install(**self.sample_install_copy, install_number=45)
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, building_node)
+
+    def test_remove_node_when_building_has_one(self):
+        building_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0)
+        building_node.save()
+
+        self.building_1.primary_node = building_node
+        self.building_1.save()
+
+        install = Install(**self.sample_install_copy, install_number=45)
+        install.node = building_node
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, building_node)
+
+        install.node = None
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, None)
+
+    def test_set_install_to_different_to_building(self):
+        building1_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0)
+        building2_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0)
+        building1_node.save()
+        building2_node.save()
+
+        self.building_1.primary_node = building1_node
+        self.building_1.save()
+
+        building2 = Building(**sample_building)
+        building2.primary_node = building2_node
+        building2.save()
+
+        install = Install(**self.sample_install_copy, install_number=45)
+        install.node = building1_node
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, building1_node)
+
+        install.building = building2
+        install.save()
+
+        install.refresh_from_db()
+        self.assertEqual(install.node, building1_node)
+
     def test_construct_install_yes_id_no_install_number(self):
         install = Install(
             id=uuid.UUID("23ef170c-f37d-44e3-aaac-93dae636c86e"),
diff --git a/src/meshapi/tests/test_nn.py b/src/meshapi/tests/test_nn.py
index f02aa894..9216659b 100644
--- a/src/meshapi/tests/test_nn.py
+++ b/src/meshapi/tests/test_nn.py
@@ -28,8 +28,8 @@ def setUp(self):
         self.admin_c.login(username="admin", password="admin_password")
 
         # Create sample data
-        member_obj = Member(**sample_member)
-        member_obj.save()
+        self.member_obj = Member(**sample_member)
+        self.member_obj.save()
 
         self.building = Building(**sample_building)
         self.building.latitude = 4
@@ -42,7 +42,7 @@ def setUp(self):
             inst["abandon_date"] = None
 
         inst["building"] = self.building
-        inst["member"] = member_obj
+        inst["member"] = self.member_obj
 
         self.install = Install(**inst)
         self.install.install_number = 10001
@@ -109,6 +109,98 @@ def test_nn_valid_install_number(self):
             f"nn incorrect for test_nn_valid_install_number. Should be {expected_nn}, but got {resp_nn}",
         )
 
+    def test_nn_assign_set_all_installs_on_building_without_nns(self):
+        pre_existing_node = Node(status=Node.NodeStatus.ACTIVE, latitude=0, longitude=0, network_number=123)
+        pre_existing_node.save()
+
+        inst = sample_install.copy()
+        inst["status"] = Install.InstallStatus.REQUEST_RECEIVED
+        if inst["abandon_date"] == "":
+            inst["abandon_date"] = None
+
+        inst["building"] = self.building
+        inst["member"] = self.member_obj
+
+        install2 = Install(**inst)
+        install2.status = Install.InstallStatus.ACTIVE
+        install2.install_number = 10002
+        install2.node = pre_existing_node
+        install2.save()
+
+        install3 = Install(**inst)
+        install3.status = Install.InstallStatus.BLOCKED
+        install3.install_number = 10003
+        install3.save()
+
+        install4 = Install(**inst)
+        install4.status = Install.InstallStatus.CLOSED
+        install4.install_number = 10004
+        install4.save()
+
+        response = self.admin_c.post(
+            "/api/v1/nn-assign/",
+            {"install_number": self.install_number, "password": os.environ.get("NN_ASSIGN_PSK")},
+            content_type="application/json",
+        )
+
+        code = 201
+        self.assertEqual(
+            code,
+            response.status_code,
+            f"status code incorrect for test_nn_valid_install_number. Should be {code}, but got {response.status_code}",
+        )
+
+        resp_nn = json.loads(response.content.decode("utf-8"))["network_number"]
+        expected_nn = 101
+        self.assertEqual(
+            expected_nn,
+            resp_nn,
+            f"nn incorrect for test_nn_valid_install_number. Should be {expected_nn}, but got {resp_nn}",
+        )
+
+        node_object = Node.objects.get(network_number=expected_nn)
+        self.assertEqual(node_object.status, Node.NodeStatus.PLANNED)
+        self.assertEqual(node_object.latitude, self.building.latitude)
+        self.assertEqual(node_object.longitude, self.building.longitude)
+        self.assertEqual(node_object.install_date, datetime.date.today())
+
+        self.install.refresh_from_db()
+        self.assertEqual(self.install.node, node_object)
+        self.assertEqual(self.install.status, Install.InstallStatus.PENDING)
+
+        install2.refresh_from_db()
+        self.assertEqual(install2.node, pre_existing_node)
+        self.assertEqual(install2.status, Install.InstallStatus.ACTIVE)
+
+        install3.refresh_from_db()
+        self.assertEqual(install3.node, node_object)
+        self.assertEqual(install3.status, Install.InstallStatus.BLOCKED)
+
+        install4.refresh_from_db()
+        self.assertEqual(install4.node, node_object)
+        self.assertEqual(install4.status, Install.InstallStatus.CLOSED)
+
+        # Now test to make sure that we get 200 for dupes
+        response = self.admin_c.post(
+            "/api/v1/nn-assign/",
+            {"install_number": self.install_number, "password": os.environ.get("NN_ASSIGN_PSK")},
+            content_type="application/json",
+        )
+
+        code = 200
+        self.assertEqual(
+            code,
+            response.status_code,
+            f"status code incorrect for test_nn_valid_install_number DUPLICATE. Should be {code}, but got {response.status_code}",
+        )
+
+        resp_nn = json.loads(response.content.decode("utf-8"))["network_number"]
+        self.assertEqual(
+            expected_nn,
+            resp_nn,
+            f"nn incorrect for test_nn_valid_install_number. Should be {expected_nn}, but got {resp_nn}",
+        )
+
     def test_doesnt_change_the_status_of_active_nodes(self):
         self.install.status = Install.InstallStatus.ACTIVE
         self.install.save()
@@ -168,6 +260,62 @@ def test_building_already_has_nn(self):
         self.assertEqual(self.install.status, Install.InstallStatus.PENDING)
         self.assertEqual(node.status, Node.NodeStatus.ACTIVE)
 
+    def test_building_already_has_nn_but_another_install_is_missing_the_node(self):
+        node = Node(
+            network_number=9999,
+            status=Node.NodeStatus.ACTIVE,
+            type=Node.NodeType.STANDARD,
+            latitude=0,
+            longitude=0,
+        )
+        node.save()
+
+        self.building.primary_node = node
+        self.building.save()
+
+        inst = sample_install.copy()
+        inst["status"] = Install.InstallStatus.REQUEST_RECEIVED
+        if inst["abandon_date"] == "":
+            inst["abandon_date"] = None
+
+        inst["building"] = self.building
+        inst["member"] = self.member_obj
+
+        install2 = Install(**inst)
+        install2.status = Install.InstallStatus.PENDING
+        install2.install_number = 10002
+        install2.save()
+
+        response = self.admin_c.post(
+            "/api/v1/nn-assign/",
+            {"install_number": self.install_number, "password": os.environ.get("NN_ASSIGN_PSK")},
+            content_type="application/json",
+        )
+
+        code = 201
+        self.assertEqual(
+            code,
+            response.status_code,
+            f"status code incorrect for test_nn_valid_install_number. Should be {code}, but got {response.status_code}",
+        )
+
+        resp_nn = json.loads(response.content.decode("utf-8"))["network_number"]
+        expected_nn = 9999
+        self.assertEqual(
+            expected_nn,
+            resp_nn,
+            f"nn incorrect for test_nn_valid_install_number. Should be {expected_nn}, but got {resp_nn}",
+        )
+
+        self.install.refresh_from_db()
+        self.assertEqual(self.install.node, node)
+        self.assertEqual(self.install.status, Install.InstallStatus.PENDING)
+        self.assertEqual(node.status, Node.NodeStatus.ACTIVE)
+
+        install2.refresh_from_db()
+        self.assertEqual(install2.node, node)
+        self.assertEqual(install2.status, Install.InstallStatus.PENDING)
+
     def test_node_already_exists_no_nn(self):
         node = Node(
             status=Node.NodeStatus.PLANNED,
diff --git a/src/meshapi/views/forms.py b/src/meshapi/views/forms.py
index 0f3f5b4f..65af4721 100644
--- a/src/meshapi/views/forms.py
+++ b/src/meshapi/views/forms.py
@@ -580,6 +580,12 @@ def network_number_assignment(request: Request) -> Response:
         nn_install.status = Install.InstallStatus.PENDING
         dirty = True
 
+    other_building_installs = [install for install in nn_building.installs.all() if install != nn_install]
+    for install in other_building_installs:
+        if install.node is None:
+            dirty = True
+            install.node = nn_install.node
+
     # If nothing was changed by this request, return a 200 instead of a 201
     if not dirty:
         message = f"This Install Number ({r.install_number}) already has a "
@@ -601,6 +607,8 @@ def network_number_assignment(request: Request) -> Response:
         nn_install.node.save()
         nn_building.save()
         nn_install.save()
+        for install in other_building_installs:
+            install.save()
     except IntegrityError:
         logging.exception("NN Request failed. Could not save node number.")
         return Response(