In WebCP you can select SSL Redirect to either No Redirect or Redirect to HTTPS.
No Redirect: In this mode there is no redirect to SSL. If your domain is example.com then with SSL No Redirect set both http://example.com as well as https://example.com will work without a redirect.
Redirect to HTTPS: In this mode an SSL redirect is enforced. This means that if a visitor visits http://example.com then it will automatically be 301 redirected to https://example.com.