1 files changed, 3 insertions, 1 deletions

diff --git a/src/fns.c b/src/fns.c
index a4a3fb882a9..f0a387ecd21 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -709,7 +709,9 @@ concat (nargs, args, target_type, last_special)
                 else
                   {
                     XSETFASTINT (elt, XSTRING (this)->data[thisindex++]);
-                    if (some_multibyte && XINT (elt) >= 0200
+                    if (some_multibyte
+                        && (XINT (elt) >= 0240
+                            || ! NILP (Vnonascii_translation_table))
                         && XINT (elt) < 0400)
                       {
                         c = unibyte_char_to_multibyte (XINT (elt));