RE: Over-coupled or under-insulated?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

The sink drain pipe may be metal where you're connecting to it, but there's 
no guarantee that there's not a PVC segment or a neoprene coupler somewhere 
between the sink and the underground waste pipe.  For this reason, you 
should be connecting to the cold water pipe, which is more likely to be 
copper throughout it's length.  Hot water pipes should be avoided because 
the water heater is in between the supply pipe and the cold water entrance, 
and you don't want that in the ground path.

Gary Lau
MA, USA

  > the secondary is grounded ... to a sink drain pipe. The sink is
  > about 20 feet away.