The law is you have to take it before the 8th hour period... So if you are pulled over by one of our finest, and you have over 8 hours without showing a thirty minute break. You will get a costly ticket. Pretty cut and dry... They will be trying to make that easy money...
Well, kinda. The regulations state you cannot drive after having 8 hours since your last break of 30 minutes or more. You can still be on duty for however long need be.
May drive only if 8 hours or less have passed since end of driver’s last off-duty
or sleeper berth period of at least 30 minutes.