Here is the usage policy of the EPP Sandbox

1) Be nice.  Please don't hammer the sandbox with loads of EPP requests.  Others 
   want to use it too.  If we find a registrar account abusing the system, a 
   warning will be issued.  If the activity continues we'll remove the account and 
   disallow access from that registar's IPs.  But we really don't want it to come
   to that, so please, be nice.

2) Because we don't have gigs and gigs of space, the database will be refreshed 
   every so often.  Probably around once per month.  This may change as we see 
   how much action this sandbox gets.  Refreshes will be announced on the 
   epp-rtk-devel list.

3) As fixes and upgrades are done to the EPP server, the system will be updated.
   We'll try to annouce downtimes on the epp-rtk-devel list.  Downtimes should be short. 
   If no annoucement was made and connections are refused, please wait a bit and
   try again.  If it's still down after a half hour to an hour, please send a note to
   the devel list.

4) These policies may change.  Changes will be announced on the epp-rtk-devel list.

Thanks and have fun!