AC cable and BX: paper wrap, bonding strip, tear-out

Paper inside a steel spiral

AC cable, still called BX by most of the trade, is a flexible steel armour wrapped around two or three insulated conductors that are themselves wrapped in waxed paper. A flat aluminium bonding strip runs the length of the cable in contact with the armour. There is no green ground conductor, because the armour and that strip together form the equipment grounding path.

The paper is the part people forget. It keeps the conductors from chafing on the armour and it holds them in formation, but it also absorbs moisture and it tears at every cut. A coil that has been opened, cut and left in a damp basement takes water into the paper, and the paper holds it against the conductor insulation. That is why old AC often looks fine outside and smells like a cellar inside.

Why cut AC is hard to reuse

The grounding path is the whole problem. A length of AC removed from a ceiling has been bent, stapled, fished through drilled joists and pulled against its staples. Every one of those actions works the interlock. The bonding strip must stay in contact with the armour over the full length, and a spiral that has been crushed or opened at a bend no longer reliably does that.

There is also the fittings question. AC needs listed anti-short bushings and connectors matched to the armour. A used coil arrives without them, and an electrician who has to buy fittings to use a short length usually will not. That leaves the practical reuse market narrow: long, clean, unopened coils, and little else.

Tear-out in the inner-ring suburbs

Cleveland's inner-ring housing stock and the older commercial buildings along the near-east and near-west corridors are full of this cable. A kitchen or bath gut in a 1920s duplex produces a wheelbarrow of short pieces. A full rewire of a two-flat produces coils, because the crew pulls the runs out whole wherever the ceiling is open.

The distinction matters when a landlord or a small contractor calls. Bagged short pieces from a gut are scrap. Coils pulled whole from a rewire, still in their original runs and coiled the way they came out, are worth a look. Lakewood and the west-shore streets add a wrinkle: alley access and no loading dock, so the material comes out through a gangway and down a driveway.

What is realistic to send

Be plain about the mix. A tear-out lot is usually mostly short, and describing it as a hundred feet of coil when it is forty short pieces and three coils wastes everyone's afternoon.

• Coils kept separate from bagged short pieces
• Approximate length of each whole coil
• Whether the armour is straight or crushed at the bends
• Condition of the paper at the cut ends, dry or damp
• Whether the cable came out whole or was cut at every box