This isnt something you really want to have to do on a regular basis, if an account is getting locked on a regular basis you should really go find out who or what is causing this than just setting the account to never lock. But some times you have to do this. So here we go
Where do i go to check lock account on X amount of logins is enabled
/etc/default/login = Tells you how many failed logins before the account is locked.
/etc/security/policy.conf = Informs you if the policy is enabled (check for entyr LOCK_AFTER_RETRIES)
so to set an account to never become locked all you need to do is add it into /etc/user_attr e.g. (user jbloggs)
jbloggs::::lock_after_retries=no