I'm working on a residential wiring project. I'm trying to figure out how to connect a 1/2" flexible aluminum conduit to a 3/4" knockout on a junction box. The existing junction box is situated such that the knockout facing the direction the conduit will run is 3/4". For convenience, I'd like to use the 3/4" knockout. The conduit will hold only two conductors plus ground, so 1/2" conduit is plenty large, and that's the conduit I have on hand. Is there a name for an off the shelf fitting that does this?

  • 4
    There are reducing washers that are code legal like these: acehardware.com/departments/lighting-and-electrical/… Jan 14 at 7:26
  • Just an installation note, two reducing washers are used at each KO, one inside the box, one outside, both the same direction. Jan 14 at 14:36
  • "Questions seeking product or service recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve." While you've specified the problem, asking for specific product recommendations is explicitly off-topic. What's available for sale today may be discontinued tomorrow, and we look to have answers that can stand the test of time. VtC.
    – FreeMan
    Jan 14 at 14:38
  • OTOH, there are junction boxes with 1/2" knockouts and there are tools to make your own knockout of whatever size you desire. It may be easier to simply replace the box with one that fits your conduit. AIUI, the knockout punch sets are rather pricey and are really only in the domain of professional electricians. You might find one in the neighborhood who would let you borrow his or do the job for a few bucks/6-pack.
    – FreeMan
    Jan 14 at 14:40
  • 2
    @GeorgeAnderson You should write that up as an answer. Jan 14 at 15:39

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