Are these proper connections?

I’m used to seeing large, chunky dialectric connectors that look like a large nut (with flat sides for wrench tightening).

But I have heard there are other types of dialectric connectors for connecting steel to copper.

Are these connections fitted with proper connectors that will resist galvanic reaction?



Hi to all,

Jeff, in a word no. PTFE (Teflon) tape does not meet the requirements of a dialect connection.



Hi Gerry,

Thanks… I wasn’t really wondering about the teflon tape. We both know that won’t work.

I was questioning whether the steel connectors (90 degrees in first picture and cylindrical/straight in the second picture) between the steel and copper might have some sort of “seperator” inside them to keep the two metals from coming in contact…like a normal dialictric connector does.

What do you think?


As a plumber I would have cut the elbows out and used PVC with no hub connectors. Why they used expensive copper is beyond me. Let along the extra time it would take to do it that way. It is not the best way to go but I’ve seen something like this hold up for years.

DWV copper is thicker and will last years. As a side note. When you see old copper drain runs they will rot out the bottom. They usually start as a channel in the bottom of the copper and eventually eat through.

Okay, but do you think they have separated the copper from the steel inside?

Yes… but, it is not totally unacceptable. Like I said, I’ve seen these last for years without ill effect. Electrolysis seems to be worse on the hot side of potable water lines. If I were to say gig this or no gig this I would have to say no. Any metal material will eventually degrade. You can not put a time line on when it will start or if it even will. Just because you have a connection with two dissimilar metals does not always mean it will degrade one or the other. Just copper it’s self, depending on the water, will develop problems. I worked at a McDonalds that had at least twenty-five patches in the copper before they finally got smart and replaced it all with pex.

If that’s a brass nipple between the steel and copper piping it will act like a dialectric insulator.

Are you saying that brass will not have a galvanic reaction with either steel or copper?

How do you tell the difference between copper and brass?

The transition should be ok, the brass should work as a dielectric nipple between the galv. and the copper. It appears this repair was done with a little thought.

My personnel opinion is that they went through a lot of work and expense to do this project when it could have been done with PVC. A brass nipple that size is expensive. Copper that size is also expensive. All the work to sweat on the female adapters and all is a waste of time.

As far as a way to separate the two metals I would not use a dielectric union in DWV. Sure way to cause a blockage. I don’t know of any material that will completely separate the two materials and still make a water tight connection.