diff --git a/core/lib/Drupal/Core/Config/ConfigPrefixLengthException.php b/core/lib/Drupal/Core/Config/ConfigPrefixLengthException.php
new file mode 100644
index 0000000..695a19b
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/ConfigPrefixLengthException.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+* @file
+* Contains \Drupal\Core\Config\ConfigPrefixLengthException.
+*/
+
+namespace Drupal\Core\Config;
+
+/**
+* Exception thrown when the config prefix length is exceeded
+*/
+class ConfigPrefixLengthException extends ConfigException {}
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
index 9a61693..9ea5df3 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
@@ -8,6 +8,8 @@
 namespace Drupal\Core\Config\Entity;
 
 use Drupal\Core\Entity\EntityType;
+use Drupal\Core\Config\ConfigPrefixLengthException;
+use Drupal\Component\Utility\String;
 
 /**
  * Provides an implementation of a config entity type and its metadata.
@@ -35,17 +37,24 @@ public function getControllerClasses() {
    */
   public function getConfigPrefix() {
     if (isset($this->config_prefix)) {
-      $config_prefix = $this->config_prefix;
+      $config_prefix = $this->provider . '.' . $this->config_prefix;
     }
     else {
-      $config_prefix = $this->id();
+      $config_prefix = $this->provider . '.' . $this->id();
+    }
+
+    if (drupal_strlen($config_prefix) > 83) {
+      throw new ConfigPrefixLengthException(String::format('The @config_prefix config_prefix length is larger than the maximum limit of @char_count characters', array(
+        '@config_prefix' => $config_prefix,
+        '@char_count' => 83,
+      )));
     }
     // Ensure that all configuration entities are prefixed by the module that
     // provides the configuration entity type. This ensures that default
     // configuration will be created as expected during module install and
     // dependencies can be calculated without the modules that provide the
     // entity types being installed.
-    return $this->provider . '.' . $config_prefix;
+    return $config_prefix;
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
new file mode 100644
index 0000000..0a36508
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
@@ -0,0 +1,70 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Config\Entity\ConfigEntityTypeTest.
+ */
+
+namespace Drupal\Tests\Core\Config\Entity;
+
+use Drupal\Tests\UnitTestCase;
+use Drupal\Core\Config\Entity\ConfigEntityType;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Config\Entity\ConfigEntityType
+ *
+ * @group Drupal
+ * @group Config
+ */
+class ConfigEntityTypeTest extends UnitTestCase {
+
+  /**
+   * The entity under test.
+   *
+   * @var \Drupal\Core\Config\Entity\ConfigEntityBase|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $entity;
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getInfo() {
+    return array(
+      'description' => '',
+      'name' => '\Drupal\Core\Config\Entity\ConfigEntityType unit test',
+      'group' => 'Entity',
+    );
+  }
+
+  /**
+   * Test that we get an exception if getConfigPrefix() returns a ConfigPrefixLengthException
+   *
+   * @expectedException \Drupal\Core\Config\ConfigPrefixLengthException
+   * @covers ::getConfigPrefix()
+   */
+  public function testConfigPrefixLengthExceeds() {
+    $this->entity = new ConfigEntityType(array(
+      'provider' => $this->randomName(20),
+      'config_prefix' => $this->randomName(70),
+    ));
+    $this->assertEmpty($this->entity->getConfigPrefix());
+  }
+
+  /**
+   * Test that we do not get a ConfigPrefixLengthException and that we get the expected output
+   *
+   * @covers ::getConfigPrefix()
+   */
+  public function testConfigPrefixLengthNormal() {
+    $entity_data = array(
+      'provider' => $this->randomName(20),
+      'config_prefix' => $this->randomName(40),
+    );
+    $this->entity = new ConfigEntityType($entity_data);
+    $expected_prefix = $entity_data['provider'] . '.' . $entity_data['config_prefix'];
+    $this->assertEquals($expected_prefix, $this->entity->getConfigPrefix());
+  }
+
+
+}