UF-B just has the added benefit of being able to be direct buried (Edited to state that this statement was wrong. Keep reading the thread to get the correct response).

It can be used in every situation where UF can be used (whereas the reverse isn't true).

So other than the fact that it's more expensive, there's no need to return it and get regular UF.

B for Burial thats all that is.... might be better.

Thanks so much. What should I do with the middle (I'm guessing neutral) wire?

That's the ground wire. If this is low voltage wiring (uses a transformer), it doesn't really matter what you do with it. Just cut it off.

If this isn't low voltage wiring, you're in over your head.

Low voltage...landscape lighting. Thank you for your help!

I stand corrected! Sorry for the misinformation. I was thinking about it afterwards and I started to question my answer myself since I thought UF stood for Underground Feeder. If it's a cable that's meant for underground, then why couldn't it be direct buried?!? If it needed to be in conduit, it wouldn't be bundled into a cable, it would be individual wires.

By the way, if you're talking about the wiring on the LOW VOLTAGE side of the transfer, UF is overkill (and often more difficult to work with). There are more flexible and cheaper low voltage landscape wire available.

Oh it has a ground? Hmm maybe we need to see what you are doing here...

Yes I have decided to return it and get the correct one no need to mix wires especially with little experience I have.