diff --git a/cini/models.py b/cini/models.py
index e32adf0..5db2e98 100644
--- a/cini/models.py
+++ b/cini/models.py
@@ -367,6 +367,7 @@ def __init__(self):
             - Móvil = ``M``
         """
         self.tipo = None
+        self.punt_frontera = False  # Si True, la 5a posició del CINI es '5' (Punt Frontera)
         self.transformadores = []  # Lista de transformadores del CT
 
     @property
@@ -403,16 +404,19 @@ def cini(self):
         if self.tension_s is not None and self.tension_s < 1:
             c.positions[4] = '5'
 
-        if self.tipo == 'I':
-            c.positions[5] = '1'
-        elif self.tipo == 'C':
-            c.positions[5] = '2'
-        elif self.tipo == 'L':
-            c.positions[5] = '3'
-        elif self.tipo == 'S':
-            c.positions[5] = '4'
-        elif self.tipo == 'M':
-            c.positions[5] = '9'
+        if self.punt_frontera:
+            c.positions[5] = '5'
+        else:
+            if self.tipo == 'I':
+                c.positions[5] = '1'
+            elif self.tipo == 'C':
+                c.positions[5] = '2'
+            elif self.tipo == 'L':
+                c.positions[5] = '3'
+            elif self.tipo == 'S':
+                c.positions[5] = '4'
+            elif self.tipo == 'M':
+                c.positions[5] = '9'
 
         if self.tension is not None:
             if self.tension <= 1:
diff --git a/spec/cts_spec.py b/spec/cts_spec.py
index ed978f1..bce949b 100644
--- a/spec/cts_spec.py
+++ b/spec/cts_spec.py
@@ -63,6 +63,12 @@
                 self.ct.tipo = 'M'
                 cini = self.ct.cini
                 expect(cini[5]).to(equal('9'))
+        with context('si es Punt Frontera'):
+            with it('sobreescriu el tipo i val 5'):
+                self.ct.punt_frontera = True
+                self.ct.tipo = 'I'
+                cini = self.ct.cini
+                expect(cini[5]).to(equal('5'))
 
     with description('la sexta posicion'):
         with before.all: