diff --git a/reframe/core/config.py b/reframe/core/config.py
index ad1a1a8a50..50bc6060e2 100644
--- a/reframe/core/config.py
+++ b/reframe/core/config.py
@@ -528,6 +528,9 @@ def handler_list(handler_config):
                 f"by ReFrame based on '{filename}'.\n#\n\n"
                 f"site_configuration = {util.ppretty(converted)}\n")
 
+    contents = '\n'.join(l if len(l) < 80 else f'{l}  # noqa: E501'
+                         for l in contents.split('\n'))
+
     if newfilename:
         with open(newfilename, 'w') as fp:
             if newfilename.endswith('.json'):