Bus Duct - Busway

Note: Our website may not reflect our full in-stock inventory. If you don’t see what you need, call 1-800-328-1842 for a real-time inventory check and options. “Contact us for price” simply means we’ll quote it to confirm configuration and current pricing - not that it’s out of stock.

Square D I-Line Bus Duct AP508G | 800 Amp 277/480 Volt | 3 Phase 4 Wire W/ GRND R&G

Square D I-Line AP508G aluminum bus duct; 800 amp, three phase, four-wire with ground, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP508G
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Square D I-Line Bus Duct AP510 | 1000 Amp 277/480 Volt | 3 Phase 4 Wire R&G

Square D I-Line AP510 aluminum bus duct; 1000 amp, three phase, four-wire, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP510
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Square D I-Line Bus Duct AP510G | 1000 Amp 277/480 Volt | 3 Phase 4 Wire W/ GRND R&G

Square D I-Line AP510G aluminum bus duct; 1000 amp, three phase, four-wire with ground, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP510G
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Square D I-Line Bus Duct AP512 | 1200 Amp 277/480 Volt | 3 Phase 4 Wire R&G

Square D I-Line AP512 aluminum bus duct; 1200 amp, three phase, four-wire, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP512
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Square D I-Line Bus Duct AP512G | 1200 Amp 277/480 Volt | 3 Phase 4 Wire W/ GRND R&G

Square D I-Line AP512G aluminum bus duct; 1200 amp, three phase, four-wire with ground, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP512G
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Square D I-Line Bus Duct AP516 | 1600 Amp 277/480 Volt | 3 Phase 4 Wire R&G

Square D I-Line AP516 aluminum bus duct; 1600 amp, three phase, four-wire, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP516
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Square D I-Line Bus Duct AP516G | 1600 Amp 277/480 Volt | 3 Phase 4 Wire W/ GRND R&G

Square D I-Line AP516G aluminum bus duct; 1600 amp; three phase, four-wire with ground, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP516G
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Square D I-Line Bus Duct AP520 | 2000 Amp 277/480 Volt | 3 Phase 4 Wire R&G

Square D I-Line AP520 aluminum bus duct; 2000 amp, three phase, four-wire, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP520
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Square D I-Line Bus Duct AP520G | 2000 Amp 277/480 Volt | 3 Phase 4 Wire W/ GRND R&G

Square D I-Line AP520G aluminum bus duct; 2000 amp, three phase, four-wire with ground, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: AP520G
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Square D I-Line Bus Duct CP302 | 225 Amp 600 Volt | 3 Phase 3 Wire R&G

Square D I-Line CP302 Square D I-Line bus duct; 225 amp, three phase, three-wire, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP302
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Square D I-Line Bus Duct CP302G | 225 Amp 600 Volt | 3 Phase 3 Wire W/ GRND R&G

Square D I-Line CP302G copper bus duct; 225 amp, three phase, three-wire with ground, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP302G
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Square D I-Line Bus Duct CP304 | 400 Amp 600 Volt | 3 Phase 3 Wire R&G

Square D I-Line CP304 copper bus duct; 400 amp, three phase, three-wire, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP304
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Square D I-Line Bus Duct CP304G | 400 Amp 600 Volt | 3 Phase 3 Wire W/ GRND R&G

Square D I-Line CP304G copper bus duct; 400 amp, three phase, three-wire with ground, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP304G
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Square D I-Line Bus Duct CP306 | 600 Amp 600 Volt | 3 Phase 3 Wire R&G

Square D I-Line CP306 copper bus duct; 600 amp, three phase, three-wire, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP306
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Square D I-Line Bus Duct CP306G | 600 Amp 600 Volt | 3 Phase 3 Wire W/ GRND R&G

Square D I-Line CP306G copper bus duct; 600 amp, three phase, three-wire with ground, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP306G
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Square D I-Line Bus Duct CP308 | 800 Amp 600 Volt | 3 Phase 3 Wire R&G

Square D I-Line CP308 copper bus duct; 800 amp, three phase, three-wire, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP308
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Square D I-Line Bus Duct CP308G | 800 Amp 600 Volt | 3 Phase 3 Wire W/ GRND R&G

Square D I-Line CP308G copper bus duct; 800 amp, three phase, three-wire with ground, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP308G
Contact us for pricing:

Square D I-Line Bus Duct CP310 | 1000 Amp 600 Volt | 3 Phase 3 Wire R&G

Square D I-Line CP310 copper bus duct; 1000 amp, three phase, three-wire, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP310
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Square D I-Line Bus Duct CP310G | 1000 Amp 600 Volt | 3 Phase 3 Wire W/ GRND R&G

Square D I-Line CP310G copper bus duct; 1000 amp, three phase, three-wire with ground, 600 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP310G
Contact us for pricing:

Square D I-Line Bus Duct CP502 | 225 Amp 277/480 Volt | 3 Phase 4 Wire R&G

Square D I-Line CP502 cooper bus duct; 225 amp, three phase, four-wire, 277/480 volt. Reconditioned and guaranteed with a one year warranty.
SKU: CP502
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When your busway run needs a section replaced or extended, you need a supplier who can pull the right piece today. EMSCO stocks over 25+ miles of bus duct across all major manufacturers and families, in both copper and aluminum, plug-in and feeder styles, and legacy series that are no longer manufactured. 

Shop by Family — Quick Start

If you already know your system, use the Series filter above to narrow fast. These are the families we see most often for replacements, run extensions, and emergency calls:

  • General Electric — Armor-Clad, Spectra & Spectra Low Amp, FVK
  • Square D — I-Line I & II, Round Bar
  • Siemens / ITE — Sentron & Sentron Low Amp, XJ-L, XL-U, XL-X
  • Cutler-Hammer — CP-2 / CP-4
  • Cutler-Hammer / Westinghouse — ST / CST 100 Amp
  • Other brands — call us: Arrow Hart, Federal Pacific, Continental / Crouse-Hinds

Not sure what series you have? Send photos of the nameplate and joint connections — details below. We'll confirm before you commit to an order.

What You Can Source Here — Fast

  • Copper and aluminum bus duct
  • 3-wire and 4-wire
  • Plug-in and feeder bus duct sections
  • Broad amp range — 100A to 5000A depending on series
  • Legacy and obsolete series — if it ran power in an industrial facility in the last 70 years, there's a good chance we have it
  • Matching tap boxes, elbows, T-sections, end caps, and joint packs to complete the run (see Accessories)

How EMSCO Helps You Win the Day

Legacy & Obsolete Systems Are Our Niche

We regularly support GE Armor-Clad, Square D I-Line, Siemens Sentron, ITE/Bulldog, Cutler-Hammer, and other older lines — exactly the stuff that's "not available" through normal channels.

Complete Runs, Not Just One Piece

Need more than a single section? We can help build out a full run, including the accessories you'll wish you'd ordered up front. Don't get halfway through an install short an elbow.

Fast Match Help

When series compatibility, conductor material, wire/ground configuration, and section length all matter, we help you confirm the exact fit before the order ships.

Speed Up the Match — Photos Work

If you want the fastest "yes, that's the one," send what you have. Even incomplete info helps:

  • Series name and part number (if visible on the label)
  • Amperage and voltage rating
  • Wire/ground configuration (3W, 4W, with or without ground)
  • Conductor material (copper or aluminum)
  • Section length (if known)
  • Photos of the nameplate/label, the joint/connection ends, and a side profile shot
Pro tip: A clear photo of the nameplate and a close-up of the connection end will often get you a confirmed match in minutes — faster than any email back-and-forth.

Refurbished Standards — What "R&G" Means Here

  • Inspected for condition, configuration, and conductor integrity
  • Cleaned and checked for safe, reliable operation
  • PEARL-certified — meets Professional Electrical Apparatus Reconditioning League standards
  • Tested and backed by a 1-year warranty

Avoid the Wrong Order

  • Series compatibility matters: Bus duct sections and bus plugs must match the same series. Armor-Clad duct takes Armor-Clad plugs — mixing families causes fit problems every time.
  • Copper vs. aluminum matters: These are not interchangeable within an existing run. Know what your system uses before ordering.
  • Plug-in vs. feeder matters: Plug-in sections have openings for bus plugs; feeder sections don't. Confirm which type you need before placing an order.
  • Wire/ground configuration matters: 3-wire and 4-wire sections are not the same. Ground bars add a fifth conductor — confirm your system's configuration.

Completing the Job — Not Just the Duct

If you're replacing a run, extending capacity, or getting a system back online, the duct sections are only part of what you need. We can help you source the related pieces that keep the project moving:

Need It Now?

Call our 24-hour emergency line or send us what you have — we'll confirm fit, condition, and availability in real time.