diff --git a/dotnet/IEC61850forCSharp/IsoConnectionParameters.cs b/dotnet/IEC61850forCSharp/IsoConnectionParameters.cs
index 9192eff3..759e7f53 100644
--- a/dotnet/IEC61850forCSharp/IsoConnectionParameters.cs
+++ b/dotnet/IEC61850forCSharp/IsoConnectionParameters.cs
@@ -142,6 +142,9 @@ namespace IEC61850
                 for (int i = 0; i < tSelector.Length; i++) 
                     nativeTSelector.value[i] = tSelector[i];
 
+				if (sSelector.Length > 16)
+					throw new ArgumentOutOfRangeException("sSelector", "maximum size (16) exceeded");
+
 				NativeSSelector nativeSSelector;
 				nativeSSelector.size = (byte) sSelector.Length;
 				nativeSSelector.value = new byte[16];
@@ -190,6 +193,9 @@ namespace IEC61850
                 for (int i = 0; i < tSelector.Length; i++) 
                     nativeTSelector.value[i] = tSelector[i];
 
+				if (sSelector.Length > 16)
+					throw new ArgumentOutOfRangeException("sSelector", "maximum size (16) exceeded");
+
 				NativeSSelector nativeSSelector;
 				nativeSSelector.size = (byte) sSelector.Length;
 				nativeSSelector.value = new byte[16];