Here are some of my attempts :)
In my case, it worked fine:
wget -O /dev/null http://example.com/cron/my-cron.php >/dev/null
Also, everything works fine (I think this is better if we have "https: //" in the url):
/usr/bin/php -q /home/user/public_html/cron/my-cron.php >/dev/null
Other:
curl -s http://example.com/cron/my-cron.php >/dev/null 2>&1
If you do not want to receive a notification email about a specific cron job, add the following line to the command: >/dev/null 2>&1
Link: http://docs.cpanel.net/twiki/bin/view/AllDocumentation/CpanelDocs/CronJobs