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Dielectric Fitting

The definition of dielectric is non-conductor or insulator.

So, by definition, the answer is that you cannot use a brass (or bronze or any other metal) valve to take the place of a dielectric union. This is not to say that it has not been done.

I have seen it argued that, if you use teflon tape on the male threads, you are, in effect creating a non-conductive situation and the effects of electrolysis would be greatly reduced if not elimated. Unfortunately, this argument, IMHO, fails to hold water (or anything else) given the fact that the teflon tape gets ripped at the peak of every thread, eliminating the insulation or dielectric effect.

Hope this helps.


  • Jerry Endler
    Jerry Endler Member Posts: 2
    Brass Valves Acting as a Dielectric Union

    Is it true that it's standard practice to use a brass valve to act as a dielectric union (specifically between steel pipe and copper tubing)in place of a true dielectric union?

    Contractor is attempting justify his installation with lots of arm waving ...
  • Jerry Endler
    Jerry Endler Member Posts: 2

    It continues to amaze me what passes for 'well, we've always done it that way!' reasons for doing something wrong.

    Thanks for your input ...
  • don_163
    don_163 Member Posts: 67
    I think

    it also would matter if its a open or closed system.

    I would not even sweat it..no pun intended if it was a closed system.

  • Marty
    Marty Member Posts: 109

    Agree especially if its a closed loop. Would use brass nipples or valves in my own house before a dielectric.
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