diff --git a/src/Owner.py b/src/Owner.py
index 641efd4d8..54ed76e49 100644
--- a/src/Owner.py
+++ b/src/Owner.py
@@ -72,6 +72,7 @@ def loadPluginModule(name):
 def loadPluginClass(irc, module):
     """Loads the plugin Class from the given module into the given irc."""
     callback = module.Class()
+    assert not irc.getCallback(callback.name())
     irc.addCallback(callback)
     if hasattr(callback, 'configure'):
         callback.configure(irc)
@@ -285,10 +286,9 @@ class Owner(privmsgs.CapabilityCheckingPrivmsg):
         the end.
         """
         name = privmsgs.getArgs(args)
-        for cb in irc.callbacks:
-            if cb.name() == name:
-                irc.error(msg, 'That module is already loaded.')
-                return
+        if irc.getCallback(name):
+            irc.error(msg, 'That module is already loaded.')
+            return
         try:
             module = loadPluginModule(name)
         except ImportError, e:
diff --git a/test/test_Owner.py b/test/test_Owner.py
index 521c05305..0b63b7807 100644
--- a/test/test_Owner.py
+++ b/test/test_Owner.py
@@ -83,6 +83,7 @@ class OwnerTestCase(PluginTestCase, PluginDocumentation):
 
     def testLoad(self):
         self.assertError('load Owner')
+        self.assertError('load owner')
         self.assertNotError('load Misc')
         self.assertNotError('list Owner')