Numerous ballast manufacturers have received and verified reports of incorrect applications of shunted bi-pin lampholders (tombstones) used with rapid-start (RS), programmed start (PS), and dimming ballasts. These incorrect applications have occurred in both new luminaires and field lamp and ballast retrofits. For the purposes of this discussion, ballasts operating T8 rapid start lamps can be divided into two classifications; rapid-start and instant-start.