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Thread: Transitioning from 1/2" EMT to 3/4" RNMC

  1. #1

    Default Transitioning from 1/2" EMT to 3/4" RNMC

    I have 1/2" EMT attached to the side of a house which comes down the wall into a weatherproof box with a receptacle. A 3/4" RNMC comes up from the ground next to the house, up the wall and into the same box using a male terminal adapter. The problem is whoever installed this didn't do it right. The weatherproox box has 3/4" hubs. The 1/2" EMT has a connecter on it inserted into the box. Just inserted. Not threaded in because it isn't the right size. What should I do to correct this? I was looking at a rigid reducing bushing which will work with an EMT fitting, but apparently they are only for use in dry locations. Should I cut the terminal adapter off the RNMC and glue on a reducer? I was looking at various reducing fittings in the Carlon catalog but I'm not quite sure I understand how they work. If I need multiple pieces, etc.

    Also, I want to make sure I am correcting some other portions of this the right way. The original installation was done with die-cast EMT set screw couplings and box fittings. I've replaced all of those with raintight fittings. How does one make RNMC entering a weatherproof box raintight? Do I glue it in or use some sort of thread sealant or anything?

    Hope this makes sense, otherwise I can draw a sketch.


  2. #2


    I would use the 3/4 to 1/2 reducer bushing. Rated for dry locations only is a joke. The threads are the same as the connector.

    If you have a LOT of water in that area, just use some teflon tape on the threads. The instructions on WP boxes tell you to use sealant on the KO plugs


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