Why does THOMSON TS 870 Switch transfer to generator source without a power failure?
- Ggabriel21Aug 28, 2025
If the Thomson Switch transfers to the generator source even without a utility power failure, it could be due to a few reasons: * A test mode might be activated, so check the TSC 80/TSC 80E status LED. * The utility supply voltage might be slightly below the voltage sensing setpoints. In this case, verify that the TSC 80 has the correct voltage configuration jumper setting for the system voltage, or that the TSC 80E has the correct voltage setting via software programming. * The utility power switching device may have tripped due to an overcurrent condition. Determine the cause of the alarm and rectify it before resetting the TSC 80/TSC 80E.








