diff --git a/src/controllers/installationController.js b/src/controllers/installationController.js
index ed83eee1..287c211c 100644
--- a/src/controllers/installationController.js
+++ b/src/controllers/installationController.js
@@ -1454,10 +1454,18 @@ exports.createMasterSlaveData = async (req, reply) => {
 
 exports.masterConnectedSlaveList = async (req, reply) => {
   try {
-    const { connectedTo } = req.params;
+    const { connectedTo, customerId } = req.params;
 
-    // Step 1: Get master device details
-    const master = await Insensors.findOne({ hardwareId: connectedTo, type: 'master' }).lean();
+    if (!connectedTo) {
+      return reply.status(400).send({ success: false, message: "connectedTo is required" });
+    }
+
+    if (!customerId) {
+      return reply.status(400).send({ success: false, message: "customerId is required" });
+    }
+
+    // Step 1: Get master device details (only for this customer)
+    const master = await Insensors.findOne({ hardwareId: connectedTo, type: 'master', customerId }).lean();
     if (!master) {
       return reply.status(404).send({
         success: false,
@@ -1465,7 +1473,7 @@ exports.masterConnectedSlaveList = async (req, reply) => {
       });
     }
 
-    // Step 2: Get tank metadata for master (including height, length, width)
+    // Step 2: Get tank metadata for master
     const tankDetails = await Tank.findOne(
       { hardwareId: connectedTo },
       {
@@ -1479,14 +1487,14 @@ exports.masterConnectedSlaveList = async (req, reply) => {
 
     const masterTypeOfWater = tankDetails?.typeOfWater || null;
 
-    // Step 3: Get slave tanks connected to master
-    const slaveTanks = await Insensors.find({ connected_to: connectedTo, type: 'slave' }).lean();
+    // Step 3: Get slave tanks connected to master and belonging to this customer
+    const slaveTanks = await Insensors.find({ connected_to: connectedTo, type: 'slave', customerId }).lean();
     const slaveCount = slaveTanks.length;
 
     // Step 4: Get latest IotData for master
     const latestIotData = await IotData.findOne({ hardwareId: connectedTo }).sort({ date: -1 }).lean();
 
-    // Step 5: Fetch order to get masterName, location, googleLocation, coordinates + summary counts
+    // Step 5: Fetch order to get masterName, location, etc.
     const order = await Order.findOne({ "master_connections.hardwareId": connectedTo }).lean();
 
     let masterOrderInfo = {};
@@ -1515,7 +1523,7 @@ exports.masterConnectedSlaveList = async (req, reply) => {
       electricals = order.electricals || [];
     }
 
-    // Step 6: Prepare master object for response
+    // Step 6: Build master response object
     const masterResponse = {
       ...master,
       isMaster: true,
@@ -1543,7 +1551,7 @@ exports.masterConnectedSlaveList = async (req, reply) => {
         t.tankhardwareId === finalHardwareId || t.hardwareId === finalHardwareId
       );
 
-      // Optionally fetch tank meta for slave too (if needed)
+      // Fetch slave's tank metadata
       const slaveTankMeta = await Tank.findOne(
         { hardwareId: slave.hardwareId },
         { height: 1, length: 1, width: 1 }
@@ -1561,7 +1569,7 @@ exports.masterConnectedSlaveList = async (req, reply) => {
       };
     }));
 
-    // Step 8: Combine master and slaves into one array
+    // Step 8: Combine into one array
     const combinedData = [masterResponse, ...processedSlaves];
 
     return reply.send({
diff --git a/src/routes/installationRoute.js b/src/routes/installationRoute.js
index ed5e0b69..23da29f6 100644
--- a/src/routes/installationRoute.js
+++ b/src/routes/installationRoute.js
@@ -405,7 +405,7 @@ module.exports = function (fastify, opts, next) {
         handler: installationController.createMasterSlaveData
       });
       
-      fastify.get("/api/getmasterConnectedSlaveData/:connectedTo", {
+      fastify.get("/api/getmasterConnectedSlaveData/:connectedTo/:customerId", {
         schema: {
           description: "Get masrter connected slave data",
           tags: ["Installation"],
@@ -414,7 +414,7 @@ module.exports = function (fastify, opts, next) {
             type: "object",
             properties: {
               connectedTo: { type: "string" },
-           
+              customerId:  { type: "string" },
             },
             required: [ "connectedTo"],
           },