Project estimator
Office or commercial building: what the job needs
Offices, headquarters, retail and clinics. Floor area, floors and the systems in scope drive panel dressing, tray and riser ties, feeder lugs, cabling straps and control terminations.
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How this estimate works
Each quantity comes from a stated rule of thumb applied to your answers. For a typical office or commercial building (50,000 sq ft standard office, 3 floors), these are the rules and the items they point to:
- NR-4x200 Harness tie, 40 lb, 7.9 in, 3.5 mm wide
- Panel dressing: 3 small ties per circuit × 294 circuits (7 panels of 42, about 1 per 7,500 sq ft)
- NR-8x370 Heavy-duty nylon tie, 120 lb, 14.6 in (370 mm)
- Power cable in tray: 2 bundles tied every 6 ft over about 1,500 ft of tray (3 ft per 100 sq ft)
- NR-9x600 Heavy-duty nylon tie, 175 lb, 23.6 in (600 mm)
- Vertical risers: 2 bundles tied every 18 in over 26 ft (1 riser, 13 ft per floor)
- NR-HL12x200 Hook-and-loop strap, 12 mm wide, 7.9 in
- Cable path: a hook-and-loop strap at each J-hook every 5 ft over about 4,000 ft, 1.5 bundles per hook
- Rack and patch-panel dressing: 3 straps per drop × 833 drops (2 per workstation, 1 workstation per 125 sq ft, plus wireless and cameras)
- NR-SLT-400 Stainless steel tie, 180 lb, 15.7 in (400 mm)
- Rooftop runs: 20 stainless ties per unit
- NR-DRS-25 Heat shrink tubing 2:1, 25 mm (1 in), 50 m roll
- Heat shrink over large lug barrels: 3 in per lug
- NR-DRS-6 Heat shrink tubing 2:1, 6 mm (1/4 in), 100 m roll
- Phase marking and repairs: 3 in of 1/4 in heat shrink per circuit
- NR-FDD2-250 Quick disconnect, female, 16 to 14 AWG, .250 in tab
- HVAC equipment connections: 6 quick disconnects per unit
- NR-SVS1.25-4 Fork terminal, 22 to 16 AWG, #8 stud, red
- Fire alarm, access control and camera devices: 1 per 400 sq ft × 2 terminals (125 devices)
- NR-E1008 Insulated ferrule, 18 AWG (1.0 mm²), 8 mm pin
- HVAC control wiring: 24 ferrules per rooftop unit × 13 units (1 per 4,000 sq ft)
- NR-SC16-6 Copper tube lug, 16 mm², 1/4 in stud
- Equipment grounding (2 per panel) and telecom bonding (3 per floor)
- NR-SC70-10 Copper tube lug, 70 mm², 3/8 in stud
- Feeders at panels and transformers: 4 large lugs per panel
We add 10% for waste and offcuts, round up to whole packs of 100 and whole rolls, and show a low to high range because real jobs vary with routing, spacing and spec. Your drawings and spec sections beat any rule of thumb: send them with your quote request and we'll price from them.