Worth mentioning to whoever bought the MES nixie clock, in case they aren't aware...
The clock is, by default, a live chassis. Ideally it should be doubly isolated for safety - just be careful with it. Mike has a big red warning about this on his site...
"Warning! As this design uses a transformerless power supply, the whole circuit is at mains potential. Disconnect before making any adjustments etc. If you need to use an oscilloscope or other grounded instrument for debugging, the circuit MUST be operated through an isolating transformer. The finished design MUST be enclosed in a suitably insulated case, and if pushbuttons are used instead of reed switches for time-setting, they must have mains rated insulation."