How to connect ductile iron to copper pipe 1

[canman]

Need help. I have a 4" ductile iron pipe, class 53, for domestic water use coming from the downstream side of a backflow device. It needs to be connected to a 4" copper pipe, type K for on-site drinking water use. Specifically, what technique should be used to connect the two for cathodic protection? If you have a certain manufacturer and model of a part that would be very helpful.

Canman

 

[willis]

You need a mechanical joint transition fitting. Get the outside circumference of both pipes, and go to the link below, they have every type of fitting you need. There are other supplier's out there, probably closer to you, you just need to know what you're looking for. As far as protection from galvanic corrosion, the only part of the m.j. coupling touching both pipes is the rubber gasket, which is your protection. A question for you- Is the backflow device installed as meter protection, meaning directly after the connection to the utility's meter?

http://www.jcmindustries.com/connection_fittings.html

 

[PUMPDESIGNER]

That link from willis is a good source.
Hate to say it, but Texas can do some things right, they sure do pipe and fittings nicely.
A guy from Texas was visiting Fort Knox and the guide said that there was enough gold there to build a five foot high fence all the way around Texas.
The Texan said, "Yeh, and if we liked it we would buy it."


PUMPDESIGNER

 

[dicksewerrat]

I'd use a mech joint sleeve with mega lug retainers. Put a blind plug on the copper side, tapped out for pipe thread. Screw in a 4 inch sweat copper to 4 inch iron pipe thread adapter and silver solder the copper in. Also put a conductivity strap from the coper to the backwater fitting. this sounds more like "hire a plumber" than engr. question.