RE: Over-coupled or under-insulated?

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

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

At 12:45 PM 3/18/2003 -0700, you wrote:
>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.


Especially since there is almost certainly a galvanic isolation coupling at 
the hot water heater.


>Gary Lau
>MA, USA
>
>  > the secondary is grounded ... to a sink drain pipe. The sink is
>  > about 20 feet away.