At present four U.S. states - North Carolina, Pennsylvania, South Carolina and Texas - do not allow wage garnishment at all except for debts related to taxes, child support, federally guaranteed...
Read this:
http://www.dol.gov/esa/whd/regs/compliance/whdfs30.pdf
We had our entire paycheck garnished this week and by FEDERAL LAW they should have only received 25% MAXIMUM!! Off to an attorney...