Bus Plugs — Emergency Build & Same-Day Stokk

When a busway tap-off fails on a production line, in a data center riser, or inside a multi-tenant switchroom, the clock starts immediately. We stock bus plugs across every common amp rating and configuration so we can get a fusible or circuit breaker unit out the same day, instead of leaving you waiting weeks for a factory order.

Our bus plug inventory covers Square D, Siemens, Eaton, GE, and Cutler-Hammer — the five busway systems that actually exist in North American industrial and commercial buildings. Whether you need a single 30A lighting tap, a 400A motor starter combination, or an 800A fusible disconnect to feed a new chiller skid, we can quote it, build it, and ship it nationwide on a turnaround that the OEM channel cannot match.

What Bus Plugs Do

Bus plugs — also called bus duct tap-offs or plug-in switches — are the disconnect-and-fuse units that plug directly into a busway section to feed an individual load. They mount into the openings on a plug-in busway run, draw power from the bus bars inside, and provide overcurrent protection plus a local disconnect for whatever sits downstream: a panelboard, a motor, a transformer, a lighting circuit, or a piece of process equipment.

Because the plug clamps onto live bus bars, it eliminates the conduit, wire pulls, and termination time that a conventional feeder run would require. That is the whole point of plug-in busway: load locations move, equipment gets added, and a new tap-off can be installed in minutes rather than days. The trade-off is that when a bus plug fails or a facility expansion needs a new tap, you have to source the correct frame size, amp rating, and protective device for the specific busway system already in the wall — and lead times on new-build units routinely run 20+ weeks.

Bus Plug Variants We Stock

Fusible Bus Plugs

Fusible bus plugs use a class J, class R, or class L fuse block as the protective device, paired with a load-break disconnect switch. Typical sizing runs from 30A through 800A at 240V, 480V, and 600V three-phase. Fusible units remain common in legacy industrial busway because the fuses are inexpensive to replace and the let-through characteristics are well understood for motor and transformer loads. We carry both new-surplus and fully refurbished fusible plugs across all five major brands.

Circuit Breaker Bus Plugs

Circuit breaker plugs use a thermal-magnetic or electronic-trip breaker as the protective device, again behind a disconnect operator. These are the standard choice for newer installations and for any application where adjustable trip settings or remote monitoring matter. Frame sizes run from 15A lighting plugs through 1600A feeder breakers, with the Square D I-Line and PowerBus (PBPQ) lines and the Eaton Pow-R-Way III being the most-requested platforms in our day-to-day quote volume.

Motor Starter Combination Plugs

Combination bus plugs integrate a fused or breaker disconnect with a motor starter inside a single bus-mounted enclosure. They are the standard for plant floors where motors are fed directly off overhead busway runs — conveyor drives, exhaust fans, pump motors, and machining centers. We stock combination units in NEMA sizes 1 through 5, and we will spec the correct overload heaters when you tell us the motor nameplate.

Lighting and Branch-Circuit Plugs

Low-amp branch plugs (typically 15A to 60A) feed lighting panels, receptacle drops, and small power circuits from a busway run. These are usually the highest-volume item in any operating facility — warehouses with continuous overhead busway lighting feeds burn through them as fixtures get added, moved, and reconfigured.

Brands and Busway Systems We Cover

Every bus plug has to match the busway it plugs into. The plug-in window pattern, the bus bar spacing, and the mechanical latch are all proprietary to the system. We carry inventory across all of them:

• Square D — I-Line, I-Line II, PowerBus (PBPQ), Saflex, PFG, and earlier PQ / PBQ / PSS / SD series
• Siemens — Sentron busway plugs, XJ-L and XL-X system plug-in units, and the legacy ITE bus plug catalog we still keep on hand for older buildings
• Eaton — Pow-R-Way III bus plugs and the older Pow-R-Way II catalog, plus Cutler-Hammer plug-in units
• GE — AL, AV, and Power Break II bus plug families for GE Spectra and earlier Armor-Clad busway
• Cutler-Hammer — full legacy catalog, including the units now badged under the Eaton brand

Tell us the busway brand, the system designation stamped on the housing, and the amp rating you need, and we will confirm a match against current stock before you commit to a PO.

Where Our Bus Plugs Get Used

Bus plugs sit behind power distribution in any building where loads move, change, or get added over the life of the facility. The applications where we ship the most volume are:

• Manufacturing plants — overhead busway feeding production line drops, motor starters, and weld receptacles
• Data centers — PDU and CRAC unit feeds from white-space and gray-space busway runs
• Multi-tenant commercial — riser busway feeding tenant panelboards floor by floor
• Warehouses and distribution centers — lighting and small power branches from continuous overhead busway
• Hospitals and labs — equipment feeds where shutdown windows are short and replacement has to happen overnight

Why Verified Breakers

The two facts that matter when a bus plug fails or a facility needs an expansion tap are stock and speed. Manufacturer lead times on new bus plugs routinely run 20+ weeks. We turn quoted units around in 24-48 hours when our stock matches your spec, drawing on inventory we hold across our Colorado, Texas, and California facilities. Every unit ships tested, with documented amp rating, voltage, and protective device data.

We have stocked bus plugs as our daily business for years, which means we know which legacy catalog numbers are still available, which ones cross-reference cleanly to current-production equivalents, and which combinations require a refurbished unit to make the deadline. That sourcing depth is what lets us hold a 24-48 hour turnaround as a standing commitment instead of a marketing claim.

Request a Bus Plug Quote

Send us the busway brand, the system designation, the amp rating, the protective device type (fusible, breaker, or motor starter), and the voltage. We will come back with a stocked-unit quote and a ship date the same business day. For urgent builds where downtime is already counting, use the priority line on the page header — we route those calls straight to a build coordinator instead of a queue.