I currently have 100' of 10/2 UF cable running underground through 3/4" PVC conduit. I need to pull the 10/2 out, and pull in 10/3 UF (or its code equivalent) to replace it. I have 3 questions: 1) Is 10/3 UF cable always produced in a flat configuration, or does some company manufacture a round 10/3 UF option? 2) Does NY code require UF if the wire is running inside of conduit? 3) If not, what would be the best alternative to 10/3 for pulling thru 100' of 3/4" conduit? Thanks!

I don't know what the specifics are in NY, but I don't know why you would want to run UF in conduit.

I usually bury PVC (sched 80) with individual THWN wire. I have always heard that even if it's in conduit, if it's buried it's still considered a wet location. THWN is suitable for wet locations (whereas THHN is only for damp). Actually most of the wire I buy these days is marked THHN/THWN.

Not being sure if your in NYC or NY State, best to check with the appropriate code office.

I do know that NYC does not allow ANY direct bury cable, without special permission, see Section 300.5A of the NYC code amendment

And since NYC has several amendments and seems to be updating their code amendments, I am not sure exactly which code is in effect. I know NYC code is very strict, and has several amendments to exceed the NEC. Not sure if the state is as strict.

You will not find any electrician considering to pull any UF cable through any conduit of any great length, only, maybe 10 or 20 feet at the most, when a sleeve is needed, and then the conduit would be oversized. UF cable is just not built for pulling through conduit.

And, no, never have seen any UF cable not made round. Even if it was, you would damage the conduit and/or the cable no matter if it is round or flat.

Best to do as omzig suggests, install conduit and pull through individual wires.

XHHW insulation copper and aluminum wire is also available, and becoming more popular, actually is a bit smaller in OD, and takes less conduit fill. XHHW does not have the thermoplastic covering that THHN/THWN has, that usually gets wrinkled and adds to the pulling friction.

Omzig is absolutely correct, any buried conduit is to be considered as a wet location.