Set conductivity of 'pec' to infinity. This only effects printing of material properties, since the update coefficients for 'pec' are set to zero.

gprMax/materials.py

@@ -130,6 +130,7 @@ class Material(object):
             EB = (e0*self.er / G.dt) - 0.5*self.se
 
         if self.ID == 'pec':
+            self.se = float('inf')
             self.CA = 0
             self.CBx = 0
             self.CBy = 0