US, Southern CA, NEC 2017
I need to transition from 1" PVC to 3/4" LFxC to connect to a weatherproof junction box with 3/4" NPT hubs.
My first thought was to glue on a socket x 1" NPT female fitting to the end of the PVC, and use a threaded adapter to connect to the 3/4" NPT male fitting on the end of the LFxC. I have seen plumbing versions of PVC bushings to go between 1" NPT to 3/4" NPT, but I assume using those is not allowed because they're not UL listed for conduit use.
Questions
- Does code allow use of a UL listed aluminum bushing like McMaster #7864T23 with non-aluminum fittings?
- If using LFMC instead of LFNC, the fittings I've found are steel – is there going to be a corrosion issue due to dissimilar metals?
- If I need to stay within the existing conduit types, is there a simple way to get from the 1" PVC to the 3/4" flex conduit fittings?
Best Answer
I'd get a weatherproof box with 1" hubs on it
Amazingly enough, weatherproof boxes with 1" hubs are a thing, although you may have to order one in through your nearest supply house (or online) instead of just stopping by the nearest big-box store. I would use one of those instead of trying to field-fabricate a swedged reducer down to 3/4", since you can use reducer bushings in the larger hubs much more easily than you can expand a smaller hub out to fit a larger conduit.