"Sacramento Dave" wrote in message
. net...

"chickenwing" wrote in message
oups.com...
how come I wasn't told about this

This is a dielectric union. This device electrically separates the
water heater from the household piping.


http://www.hammerzone.com/archives/p.../union_de/intr
o.htm


They make a Dielectric Nipple. I think that's a better choice

http://acmehardware.com/pd-5338579-D...ic-Nipple.aspx


This is not a Dielectric fitting.
This is just a nipple with a plastic sleeve, that will not insulate from the
current.
You can check this easily with a DMM. Simple continuity test.
Granted I am sure it would not corrode nearly as quickly, as a unlined
nipple. But as soon as water gets between the sleeve and the nipple. There
is a space between the plastic and the nipple from molding. Plastic shrinks
as it cools from the molding process. It will start corroding.

Rick R.