Blackburn FB4G18 FLEXIBLE BRAID 1228KCMIL 18IN LONG

The FB4G18 is a flat, flexible tin-plated copper braid connector with two bolt holes, used to bond across moving or vibrating joints where a rigid conductor would fatigue. Typical uses are bonding jumpers across expansion joints, switchgear doors and enclosure covers, transformer and motor frames, and equipment that shifts relative to a grounded structure. The braid itself is 1228 kcmil and 18 inches long.

No crimping or lugs are needed. The FB4G18 is a 2-hole braid, meaning the terminal pads are already formed and punched at both ends, so it bolts straight to a busbar, ground pad, or equipment frame. You supply the bolts, nuts and washers to match the hole size and pad drilling in your equipment, plus any anti-seize or joint compound your spec calls for.

The cataloged cable length is 18 inches, which is the braid length as Blackburn lists it. Plan your bonding path with some slack: a braid pulled taut across a joint defeats the purpose, since the flex is what absorbs the movement. If your span needs more than 18 inches of run, step up to a longer braid rather than stretching this one.

The FB4G18's conductor is tin-plated copper. The tin plating slows surface oxidation on the strands and on the terminal pads, which keeps contact resistance stable over time and makes the braid more tolerant of damp or corrosive environments than bare copper. It also avoids bare-copper-to-aluminum contact concerns when the braid lands on plated or aluminum busbar.

A flat braid is the usual choice where the joint moves. The FB4G18 is a flat, flexible conductor, so it bends repeatedly without work-hardening the way a stiff stranded cable and crimped lug assembly does, and its flat profile fits tight clearances behind panels and doors. Where the connection is static, a standard compression lug and cable is simpler. Where there is vibration, thermal expansion, or a hinged cover, use the braid.

Country of origin on the FB4G18 is the United States, which matters if you are procuring against a Buy American or domestic-preference clause on a government, utility, or federally funded project. Blackburn is the brand of record on the part, and the manufacturer part number to specify is FB4G18.

The braid is rated 1228 kcmil, so it sits above a 1000 kcmil cable in cross-section. If your grounding electrode conductor or equipment bonding jumper is sized in that range, this braid carries the equivalent copper. Sizing the jumper is driven by your overcurrent device and conductor sizing, so match the kcmil to what the drawing calls out rather than to the physical width of the braid.

It ships as a single braid, sold each. If you are bonding a run of enclosure doors or a series of expansion joints, order one per joint plus spares, since these are cut-to-length assemblies and cannot be made shorter or longer in the field without losing the finished terminal pads.