Where is this Mysterious AC Voltage Coming from?

On our utility room sink basin:

I believe it is made of ceramic-coated metal, sits on top of a metal stand and is drained via PVC pipe. The metal stand is on top of dry linoleum flooring - both the sink and the stand are stand-alone and definitely NOT touching anything else surrounding them, including the faucet that comes out of the wall (which has 0vac to ground).

Here's what I do know:
From house ground to the metal sink drain I read a steady 45vac.
From house ground to the metal stand I read a steady 52vac.
From house "hot" (118vac) to the metal stand I read a steady 171vac!!!
From house ground to PVC drain pipe is 0vac
From house ground to kitchen sink drain is 0vac

The fact that the stray and mysterious 52vac is in addition to the house "hot" informs me that it must come from another phase (only stove/dryer and h2o heater on 220vac) - HELP anyone???!!!!

Thanks in advance!
Quint