diff --git a/MAC/Tools/Power/st_ec_lib.py b/MAC/Tools/Power/st_ec_lib.py
index 071691e353cd7bc6b4e170ea18f68d1e7ab982cf..c21775b8f6a1fd1c2f97a269fc55c4f33c9403a3 100755
--- a/MAC/Tools/Power/st_ec_lib.py
+++ b/MAC/Tools/Power/st_ec_lib.py
@@ -1,3 +1,4 @@
+#!/usr/bin/python3 -B
 ## P.Donker ASTRON februari 2011
 ## station EC lib module