diff --git a/lib/git/lib.rb b/lib/git/lib.rb
index 00cc0e72..fdaf30a6 100644
--- a/lib/git/lib.rb
+++ b/lib/git/lib.rb
@@ -860,10 +860,14 @@ def meets_required_version?
 
     def command_lines(cmd, opts = [], chdir = true, redirect = '')
       cmd_op = command(cmd, opts, chdir)
-      op = cmd_op.encode("UTF-8", "binary", {
-	  	:invalid => :replace,
-		:undef => :replace
-	  })
+      if cmd_op.encoding.name != "UTF-8"
+        op = cmd_op.encode("UTF-8", "binary", {
+          :invalid => :replace,
+          :undef => :replace
+        })
+      else
+        op = cmd_op
+      end
       op.split("\n")
     end