If I remember what I read correctly, NC CSE automatically goes after the NCP when they are $500 behind or a total of 3 months, whichever comes first. Technically they can go after you if you are 30 days behind but they usually follow the $500 or 3 month thing. The things I've read are kind of contradictory and confusing there. I do know that they usually go after someone after 2 or 3 months have passed.
They will also intercept taxes at this amount, $500 with the federal IRS, if there is no public assistance involved. If there is the amount is $150. The state will intercept if you owe $50.
Yes NC is extremely hard on NCPs falling behind. They will automatically put you in jail, no matter what your reason is for being behind. They don't care if you were on your death bed! They will automatically sentence you to 30 days or until you purge yourself with the full amount you owe. NC can also bring you right back to the judge, if you haven't paid at the end of 30 days, and order you right back without even seeing the light of day. They can continue to do this for up to a year. If you are found in criminal contempt the sentence can be for 90 days and they can keep it going for up to a year.
Arrears for child support do not accrue while in jail. In other words, if someone is in jail, they are not required to pay support during that time.