diff --git a/kbcstorage/tables.py b/kbcstorage/tables.py
index 324c459..12d4773 100644
--- a/kbcstorage/tables.py
+++ b/kbcstorage/tables.py
@@ -506,7 +506,7 @@ def export_raw(self, table_id, limit=None, file_format='rfc',
         }
         if not isinstance(table_id, str) or table_id == '':
             raise ValueError("Invalid table_id '{}'.".format(table_id))
-        if limit is not None and limit is not isinstance(table_id, int):
+        if limit is not None and not isinstance(limit, int):
             raise ValueError("Invalid limit '{}'.".format(limit))
         if file_format not in ('rfc', 'escaped', 'raw'):
             raise ValueError("Invalid format '{}'.".format(file_format))