The state of South Carolina employs both criminal and administrative penalties for drivers convicted of a first DUI in South Carolina. Criminal penalties are assessed in a varying manner, based on the BAC of the driver at the time of arrest, with more severe penalties assessed in light of higher BAC.
The key to determining whether you have committed a second DUI in South Carolina is the ten year look-back period (also known as "wash out period"). In other words, a DUI offense only becomes a "second" offense if it was committed within ten years of another South Carolina DUI. Sentencing is also based on the circumstances of the arrest.