Southwire Armor lite Type Mc Aluminum Armored Cable, 12/3, 600 Volts, 250 Ft. Coil

What I used it for

I ran this Southwire 12/3 MC cable through a small workshop buildout and a couple of office branch circuits, all in metallic cable tray and EMT with set-screw MC connectors. The 250-foot coil was the right size for a few homeruns, a couple of multiwire branch circuits, and some drops without leaving me with an unwieldy leftover reel. If you’re looking to cover a medium-sized project with consistent 20-amp circuits, this format makes sense.

Construction and materials

This cable uses interlocked aluminum armor with soft-drawn copper conductors, rated 600 V. The conductors in my coil were color-coded black, red, white, and green. That’s what I expect on a 12/3 with a ground when I’m doing 120/240 splits or multiwire branch circuits. The armor is on the lighter side compared to steel-jacketed MC, which keeps the overall weight manageable and makes overhead work less fatiguing. It’s not flimsy—crush resistance felt on par with the better aluminum MC I’ve used—but I wouldn’t pick aluminum armor for high-abuse areas where I’d otherwise consider rigid or steel-clad options.

The armor seam was tight and consistent, and the print legend on the jacket was legible, which matters more than it seems when you’re labeling or proving spec during inspection.

Handling and installation

• Coil memory: It arrived bound well and didn’t spring into a tangled mess when I cut it open. There’s some typical “phone cord” memory, but it straightened with a few shakes and some reverse bends. For long pulls, a simple payout stand is worth the two minutes to set up.

• Bend performance: The bend radius was friendly for box entries and offsets. I didn’t see any tendency for the armor to spiral or separate at tighter-but-still-legal bends. It’s compliant and predictable, which speeds up rough-in.

• Cutting and prep: I used a Roto-Split armoring tool for most cuts and a hacksaw for a few tight spots. The armor sheared cleanly without tearing the paper wrap, and I didn’t nick insulation even when rushing a bit. Deburring took a couple of swipes with a reamer, and the cut edge stayed flat without fishhooks. I kept using anti-short bushings (redheads) out of habit/spec—UL doesn’t universally require them for modern MC, but many inspectors still expect to see them and they do protect the conductor at the connector.

• Pulling: Through cable tray, the cable stayed round and didn’t snag on ladder rungs. In EMT runs with two sweeps and one offset, it pulled smoothly without lubricant. Armor friction is always a factor, but with aluminum it’s manageable for moderate distances.

• Connectors: I tested with Arlington and Bridgeport straight and 90-degree MC connectors. Fit-up was positive; the armor bite was consistent, and the locknuts set square. No rattle, even on drop supports. Ground continuity tested solid across the run with the insulated green as the equipment grounding conductor.

Electrical performance and conductor quality

The conductors are soft-drawn copper with even stranding and consistent insulation thickness. Strip length was predictable; I wasn’t fighting inconsistent jackets or gummy nylon. On torque, terminations held well under spec without cold-flowing. It’s a 12 AWG cable, so you’re looking at 20 A branch circuits in the usual cases, with the expected derating if you bundle or stack multiple cables. Heat was a non-issue in service; thermal imaging under typical load showed no hotspots at connectors or tight bends.

As always, match your application to the listing: this is a 600 V Type MC cable listed for cable tray and approved raceways. If you’re planning wet locations or corrosive environments, verify the exact conductor insulation rating and armor suitability for your installation conditions.

Color coding and identification

My run had black, red, white, and green conductors—handy for multiwire branch circuits and two-pole applications. Some 12/3 MC variants ship with blue instead of red for certain commercial lighting conventions. If your design standard or spec book calls for a particular color set, confirm the print legend and conductor colors before you unspool 200 feet. The included green insulated ground is a plus; it keeps things neat and avoids reliance on the armor for equipment grounding continuity.

Code and compatibility notes

• Approved uses: Listed for cable tray and raceways; it’s a good fit for commercial interiors, exposed basement shop runs, and tenant improvements where MC is preferred over THHN in conduit for speed.

• Support and spacing: Standard MC support spacing rules apply. In cable tray, follow fill and support requirements; this cable plays nicely with ladder tray and center-mount supports.

• Derating and bundling: If you stack or bundle multiple MC runs, be mindful of conductor count for ampacity adjustment. The smaller armor OD makes side-by-side bundling tempting; don’t forget the math.

• Connectors and bushings: Use listed MC connectors sized correctly for 12/3. I recommend anti-short bushings unless your local AHJ explicitly waives them for this cable design.

Consult the NEC and your local authority for specific installations. Nothing here is a substitute for code review.

Durability and jobsite behavior

• Armor toughness: Aluminum armor resists kinks and mild impacts well. It’s not as dent-resistant as steel, but it bounced back from the usual scuffs, and cosmetic dings didn’t telegraph through to the conductors.

• Vibration and noise: On long exposed runs, aluminum MC can “ring” slightly when bumped. It’s not a functional issue, more an aesthetic one in quiet spaces. Strapping at reasonable intervals calms it down.

• Corrosion: Indoors in conditioned space and a shop with occasional humidity, I saw no oxidation or staining. For harsher environments, consider fittings with proper gaskets and evaluate whether aluminum armor is appropriate.

Value and packaging

The 250-foot coil is a smart middle ground: enough footage to get real work done without managing a heavy reel. It shipped in a protective wrap that kept the first 15 feet clean and round, so the initial pulls went smoothly. On cost per foot, it hit the price-to-performance point I expect from mainstream commercial MC. If you’re comparing to big-box offerings, you’re getting professional-grade consistency without paying a premium for branding.

What I liked

• Consistent armor seam and easy, clean cuts with a Roto-Split
• Predictable bend performance and smooth pulls through raceways
• True-to-spec 12/3 with insulated green ground and sensible color coding
• Lightweight enough for overhead runs without fatigue
• Clear jacket legend and tidy conductor strip behavior

What could be better

• Verify conductor colors before committing; some job specs are picky and variants exist
• Aluminum armor isn’t the right choice for high-abuse or harsh environments
• Coil memory is present (as with most MC); a small reel would handle even better, though it would add cost

Who it’s for

• Commercial electricians and maintenance teams running 20 A branch circuits in office, retail, and light industrial spaces
• Home shop builders who want a clean, fast install in cable tray or surface raceway without pulling THHN
• Anyone needing a listed MC solution for cable tray with predictable handling and mainstream fittings

If you need maximum mechanical protection or have exposure to corrosive atmospheres, consider steel-jacketed MC or a different wiring method. For wet locations, double-check the specific insulation ratings for your application and choose accordingly.

Recommendation

I recommend this Southwire 12/3 MC cable for interior branch circuits in cable tray and approved raceways. It’s easy to cut, bends predictably, and terminates cleanly with common connectors. The soft-drawn copper conductors strip and land without fuss, and the aluminum armor keeps weight down without compromising day-to-day durability. As long as you verify that the conductor color set matches your spec and your environment suits aluminum armor, it’s a reliable, cost-effective choice that helps you move faster without sacrificing quality.