By default the SSL usage is disabled. The SSL protocol can be turned on/off through the UseSSL parameter of the Custom string property of the connection.

In order to enable it, you would need to add a parameter to the Custom string with the following value: "UseSSL=true", and you would need to set the "ClientCertificate" and the "ClientKey" file names. The latest two can be either a relative file name or a fully qualified file name (including the full path to the certificate file).

Example:

SQLConnection.Params.Add('Custom string=UseSSL=true,
  "ClientCertificate=c:\ssl\client-cert.pem",
  "ClientKey=c:\ssl\client-key.pem"');