diff --git a/core/lib/Drupal/Core/Config/ConfigCachePrimeSubscriber.php b/core/lib/Drupal/Core/Config/ConfigCachePrimeSubscriber.php
index fd5d2bd..4b38d30 100644
--- a/core/lib/Drupal/Core/Config/ConfigCachePrimeSubscriber.php
+++ b/core/lib/Drupal/Core/Config/ConfigCachePrimeSubscriber.php
@@ -32,8 +32,8 @@ public function onConfigCachePrimeGetSettingsNames(ConfigCachePrimeEvent $event)
   /**
    * {@inheritdoc}
    */
-  static function getSubscribedEvents() {
-    $events['config.prime.cache'][] = array('onConfigCachePrimeGetSettingsNames');
+  public static function getSubscribedEvents() {
+    $events[ConfigEvents::PRIME][] = array('onConfigCachePrimeGetSettingsNames');
     return $events;
   }
 
diff --git a/core/lib/Drupal/Core/Config/ConfigEvents.php b/core/lib/Drupal/Core/Config/ConfigEvents.php
index 0b0bb3a..bcc95bc 100644
--- a/core/lib/Drupal/Core/Config/ConfigEvents.php
+++ b/core/lib/Drupal/Core/Config/ConfigEvents.php
@@ -57,4 +57,11 @@
    */
   const IMPORT = 'config.importer.import';
 
+  /**
+   * Name of event fired when config cache is primed.
+   * @see \Drupal\Core\Config\ConfigFactory::getCachePrimeNames().
+   * @see \Drupal\Core\Config\ConfigCachePrimeSubscriber::getSubscribedEvents().
+   */
+  const PRIME = 'config.prime.cache';
+
 }
diff --git a/core/lib/Drupal/Core/Config/ConfigFactory.php b/core/lib/Drupal/Core/Config/ConfigFactory.php
index 7d9f541..51d0680 100644
--- a/core/lib/Drupal/Core/Config/ConfigFactory.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactory.php
@@ -158,7 +158,7 @@ public function get($name) {
    */
   public function loadMultiple(array $names) {
     if (!$this->isCachePrimed) {
-      $names = array_unique($names + $this->getCachePrimeNames());
+      $names = array_unique(array_merge($names, $this->getCachePrimeNames()));
     }
 
     $list = array();
@@ -251,7 +251,7 @@ protected function getCachePrimeNames() {
     // dispatching the event to avoid unintended recursion.
     $this->isCachePrimed = TRUE;
     $config_cache_prime_event = new ConfigCachePrimeEvent();
-    $this->eventDispatcher->dispatch('config.cache.prime', $config_cache_prime_event);
+    $this->eventDispatcher->dispatch(ConfigEvents::PRIME, $config_cache_prime_event);
     return $config_cache_prime_event->getNames();
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Config/ConfigFactoryTest.php b/core/tests/Drupal/Tests/Core/Config/ConfigFactoryTest.php
new file mode 100644
index 0000000..8f2a1ec
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Config/ConfigFactoryTest.php
@@ -0,0 +1,67 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Tests\Core\Config\ConfigFactoryTest
+ */
+
+namespace Drupal\Tests\Core\Config;
+use Drupal\Core\Config\ConfigFactory;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests the ConfigFactory.
+ *
+ * @group Config
+ */
+class ConfigFactoryTest extends UnitTestCase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getInfo() {
+    return array(
+      'name' => 'Config factoryt test',
+      'description' => 'Tests the Config factory.',
+      'group' => 'Configuration',
+    );
+  }
+
+  /**
+   * Tests loading multiple with prime config names.
+   */
+  public function testLoadMultipleWithCachePrimeNames() {
+
+    $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
+
+    $config_data = array('test1' => array('config1'), 'prime1' => array('config2'));
+    $storage->expects($this->once())
+      ->method('readMultiple')
+      ->with(array('test1', 'prime1', 'prime2', 'language1'))
+      ->will($this->returnValue($config_data));
+
+    $event_dispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+    $typed_config_manager = $this->getMockBuilder('\Drupal\Core\Config\TypedConfigManager')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $config_factory = new TestConfigFactory($storage, $event_dispatcher, $typed_config_manager);
+
+    $names = ['test1'];
+
+    $configs = $config_factory->loadMultiple($names);
+
+  }
+
+}
+
+class TestConfigFactory extends ConfigFactory {
+
+  protected function getCachePrimeNames() {
+    return array('prime1', 'prime2');
+  }
+
+  public function getLanguageConfigNames(array $names) {
+    return array('language1');
+  }
+}