diff --git a/src/ORM/Table.php b/src/ORM/Table.php
index 2e463235323..366a23a2e7f 100644
--- a/src/ORM/Table.php
+++ b/src/ORM/Table.php
@@ -17,6 +17,7 @@
 use ArrayObject;
 use BadMethodCallException;
 use Cake\Core\App;
+use Cake\Database\Connection;
 use Cake\Database\Schema\Table as Schema;
 use Cake\Database\Type;
 use Cake\Datasource\EntityInterface;
@@ -397,6 +398,11 @@ public function connection($conn = null)
         if ($conn === null) {
             return $this->_connection;
         }
+
+        if (!($conn instanceof Connection)) {
+            throw new RuntimeException('$conn must be an instance of \Cake\Database\Connection');
+        }
+
         return $this->_connection = $conn;
     }
 
diff --git a/tests/TestCase/ORM/TableTest.php b/tests/TestCase/ORM/TableTest.php
index a412b65a44e..e9ddb0f8126 100644
--- a/tests/TestCase/ORM/TableTest.php
+++ b/tests/TestCase/ORM/TableTest.php
@@ -185,6 +185,19 @@ public function testConnection()
         $this->assertSame($this->connection, $table->connection());
     }
 
+    /**
+     * Tests exception is thrown in connection is not instance of
+     * \Cake\Database\Connection
+     *
+     * @expectedException \RuntimeException
+     * @expectedExceptionMessage $conn must be an instance of \Cake\Database\Connection
+     * @return void
+     */
+    public function testConnectionException()
+    {
+        $table = new Table(['table' => 'users', 'connection' => 'default']);
+    }
+
     /**
      * Tests primaryKey method
      *