Government-mandated payroll taxes include Medicare taxes, Social Security taxes and federal income taxes are mandatory deductions. Voluntary deductions are amounts paid for items such as 401(k) plans, insurance plans and sometimes union and uniform dues. Child support payments can be automatically withheld from an employee’s payroll check, as well as garnishments that are court-ordered. These are considered “involuntary” deductions.
The 30x MW applies when deducting garnishments from an employee’s pay: https://www.dol.gov/whd/regs/compliance/whdfs30.pdf
If your main concern is a very minimal paycheck after taxes and health insurance or other “voluntary” deductions, then you likely have no real concern. When a deduction goes to the benefit of the worker and is not a court-ordered garnishment, the 30x MW does not apply.
February 2018