Blackburn FB3XD24-1 FLEXIBLE BRAID 316.8KCMIL, 24 LONG

The FB3XD24-1 is a flat flexible braided bonding jumper made of tin-plated copper, rated 316.8 KCMIL and 24 inches long. It bridges two points that move relative to each other, or that can't be bonded with rigid conductor: transformer and switchgear connections, substation equipment, bus bar to enclosure bonding, and expansion or vibration joints. The braid flexes so the bond survives thermal movement and equipment vibration that would work-harden and crack a solid conductor.

One hole per end. It is a 1-hole flexible braid connector, so each terminal pad takes a single bolt. If your equipment pad is drilled for two-hole NEMA spacing, this braid won't land on it correctly and you need a 2-hole version instead.

It carries UL E3060 and CSA LR29625. That covers you on submittals for jobs that call for listed bonding components on both sides of the border. It's also made in the United States, which matters where Buy American or domestic-content language applies.

The 24 inch figure is the cable length of the braid itself, listed as 24 in. When you're laying out a bonding run, allow for the terminal pads on each end plus some slack, because a braid pulled taut defeats the point of using flexible braid in the first place.

The tin plating on the copper braid slows oxidation at the strands and at the bolted joint, which keeps contact resistance from climbing over time. That matters in damp, outdoor, or corrosive environments, and it's the right choice when the braid lands on aluminum or galvanized equipment, where bare copper in contact with dissimilar metal is a galvanic problem.

Use flexible braid wherever the two bonded points move: equipment on vibration isolators, hinged doors and covers, bus sections that expand and contract thermally, or anything you need to disconnect for service. A cable jumper is fine on a fixed, static bond and is easier to route around corners. Where there is motion, a flat flexible braid like the FB3XD24-1 distributes the flex across many fine strands rather than concentrating it at one point.

It's a 316.8 KCMIL braid, which puts it between 300 and 350 KCMIL of copper cross-section. Compare that against the bonding jumper size your one-line or NEC table calls for rather than against the physical width of the braid, since a flat braid looks larger than round cable of the same area.

It's sold each, one braid per unit. Order one per bonding point, and count both ends of every jumper you need on the drawing before you place the order. No mounting bolts or washers are included with the braid, so pick up hardware sized to your equipment pads separately.

Blackburn FB3XD24-1 is the manufacturer part number, and it's the full call-out: 316.8 KCMIL flat tin-plated copper braid, 24 inches, one hole per end. Blackburn's FB series runs several lengths and ampacities under similar numbering, so quote the whole number rather than just the FB3XD prefix.