Southwire 12 to 3 UF-B Direct Burial Cable Review (2026): The

Why you should trust this review

I bought a coil of this cable myself for a landscape lighting circuit at my own house. Southwire did not send it, did not know I was writing about it, and had no say in what I report. I ran roughly 100 feet of it into a trench across my yard, made every connection, and lived with the result through the first month of soil settlement. That is the only kind of research that tells you anything about a direct-burial cable, because the whole question is whether it survives being buried and forgotten.

I have wired enough outdoor projects to know that the cheap route almost always costs more in the end. A generic underground cable that fails its first wet season means digging the trench again, and a trench is the expensive part. So when I evaluate UF-B, I am asking whether it earns its keep over the life of the install, not whether it saves a few dollars at the register. Everything here is from putting this exact cable in the ground.

How we evaluated

I installed about 100 feet of the 12/3 UF-B for a low-voltage landscape lighting circuit, trenching to code depth and routing the cable through a run that included two turns and a transition up out of the soil to a junction. I tested how the cable behaved when pulling it through tight bends, how the jacket stripped for terminations, and whether the gray UV-resistant jacket showed any damage from contact with soil and rock. After backfilling, I checked the circuit through the first month as the trench settled, watching for any sign of a compromised connection or moisture intrusion. I also weighed a length to confirm the heft and compared its stiffness to the indoor NM-B I keep on hand.

Direct burial rating and code compliance

The reason you buy UF-B over Romex is that you can put it directly in the ground without running it inside conduit. This cable is rated and listed for exactly that, and the solid molded jacket around the conductors is what makes the difference. Unlike indoor NM-B, where the conductors sit loose inside a paper-wrapped jacket, the UF-B insulation is bonded tight, so soil moisture has nowhere to wick in. My inspector accepted it without comment, which is the practical test that matters. Southwire is a name building departments recognize, and that alone removes friction from a permitted job.

The 12-gauge copper with ground handles a 20-amp circuit, which covers most outdoor outlets and dedicated lighting runs. If your project is lighter, a 14-gauge UF-B saves money, but I would rather have the headroom on an outdoor circuit I am only going to bury once.

Material durability and jacket toughness

The gray jacket is built for UV exposure and ground contact, and after a month underground my run showed no degradation at the points where I could inspect it. The jacket shrugged off contact with rocky backfill, and I had no concern about it abrading through. This is the part of a direct-burial cable you are really paying for, and Southwire delivers a jacket that feels genuinely robust rather than thin and brittle the way bargain cable often does. The one caution I will repeat: UF-B resists soil contact, not impact from above. A weed trimmer or a careless shovel will still damage it, so burial depth and routing matter.

Connection ease and flexibility

Stripping the UF-B jacket takes more effort than indoor Romex because the insulation is bonded so tightly to the conductors. It is not difficult, but plan on a sharper blade and a slower hand to avoid nicking copper. Once stripped, the connections are completely standard and went together without trouble. The trade-off for that tough jacket is stiffness. This cable is noticeably less flexible than NM-B, and pulling it through tight bends or a packed conduit sleeve takes muscle. At roughly 8 pounds per 100 feet, a full coil is heavy to wrestle into a trench. None of that is a flaw, it is just the nature of a cable engineered to survive in the ground, and it is worth knowing before you order.

Who should buy the Southwire 12/3 UF-B cable?

Buy it if you are doing any outdoor electrical work that requires direct burial: landscape lighting, a detached structure feed, an outdoor outlet, or a run that transitions below grade. The 20-amp capacity gives you flexibility, the brand sails through inspection, and the jacket is built to last underground. It is the safe, code-honest choice for a job you only want to do once.

Skip the 12-gauge if your project is genuinely low-power, like a small landscape transformer run, where 14/3 UF-B costs less and does the job. And skip UF-B entirely for indoor dry-location wiring, where it is overkill and standard NM-B is cheaper and easier to pull.

The verdict

After burying 100 feet of it for landscape lighting, the Southwire 12/3 UF-B is the direct-burial cable I would put in any outdoor or below-grade run. The UF-B rating earns its keep by eliminating conduit, the 12-gauge copper handles a real 20-amp circuit, and the brand carries the inspector confidence that smooths a permitted job. It is heavier and stiffer than indoor cable, and the tight-bonded jacket asks for a more careful strip, but those are the costs of a cable built to survive in soil. For outdoor work where reliability over the long haul is the whole game, this is the cable I trust and the one I will buy again.