Case Study — Residential High-Rise
Luxury High-Rise Residential Electrical Estimate — Miami, FL
Project Overview
Full electrical estimate for a 42-story luxury residential tower with 286 condominium units, ground floor retail, amenity decks (pool, fitness, club room), and 3 levels of parking. Scope included: dual 4000A services from FPL, main-tie-main switchboard arrangement, (6) 1500kVA transformers in the basement vault, (28) 277/480V panelboards, (16) 208/120V step-down transformers, emergency generator (1.5MW) with automatic paralleling, full fire alarm and voice evacuation system, amenity deck lighting and power, parking garage EV-ready rough-ins, and the residential unit meter stacks with individual unit subpanels.
CSI MasterFormat Divisions Covered
26 05 00, 26 05 13, 26 05 33, 26 08 00, 26 09 23, 26 22 00, 26 24 00, 26 24 16, 26 27 26, 26 32 00, 26 36 00, 26 51 00, 26 56 00, 28 31 00, 28 33 00
Estimating Challenges
- Florida Building Code HVHZ wind-load requirements for the Miami-Dade High Velocity Hurricane Zone required all rooftop equipment to be NOA-certified with specific anchorage calculations — (4) AHUs and the generator exhaust had electrical connections requiring wind-rated fittings at $18,000 additional cost
- FPL required the main switchboard to be in a flood-proof vault (Base Flood Elevation +1 foot) — the basement vault design showed standard construction, requiring a ($42,000) redesign add for flood-rated equipment and curbing
- The amenity deck pool electrical (lighting, pumps, GFCI receptacles) had bonding requirements per NEC 680 that were not detailed in the design — the takeoff had to include grounding grid and bonding conductor quantities from first principles
- Unit meter stacks (28 total, servicing 286 units) had 17 different configurations based on unit type — each required individual takeoff because the meter stack arrangements varied by floor plan
Change Order Prevention
During the takeoff review process, our team identified the following scope gaps that would have become change orders if not caught at the estimating stage:
- Identified that (12) of the 28 meter stacks required CT-rated metering per FPL requirements but only (8) were shown on the riser diagram — ($26,000) add
- Caught that the amenity deck EV charging stations (6 units) required load management equipment per NEC 625 that was not in the specification — ($14,000)
- Flagged that the residential unit bathroom exhaust fan ducting required per-code GFCI protection that was shown on the plans as standard receptacles — ($8,200)
Labor Forecasting
Applied high-rise construction factors per NECA MLU with 12% productivity reduction for vertical material handling (hoisting limitations, floor-to-floor coordination). Miami IBEW LU 349 rates applied with 6-day work weeks during the first 18 months. Budgeted for 2 tower cranes with electrical material hoisting windows on alternating floors. Included $45,000 for temporary power and lighting during construction across 42 floors.
Material Escalation Strategy
Copper bus switchgear and generator were the primary escalation risks. The 1.5MW generator (28-week lead time) was priced with an 8-week firm quote window — the GC placed the order at week 6, securing the pricing. All unit meter stacks were procured as a single package from a single manufacturer — this allowed 5% volume discount and ensured consistent lead times across all 28 stacks. Copper wire pricing was locked via 60-day quotes with quarterly review triggers.
Budget Comparison
| Line Item | Initial Estimate | Final Bid | Variance |
|---|---|---|---|
| Service & Switchboard | $1,240,000 | $1,306,000 | +5.3% |
| Transformers & Vault | $680,000 | $722,000 | +6.2% |
| Meter Stacks & Panels | $890,000 | $916,000 | +2.9% |
| Lighting & Controls | $742,000 | $768,000 | +3.5% |
| Generator & Emergency | $580,000 | $612,000 | +5.5% |
| Labor & Hoisting | $968,000 | $1,033,000 | +6.7% |
| Total | $4,840,000 | $5,066,000 | +4.7% |
Risk Mitigation
Conducted a pre-bid coordination meeting with FPL to confirm service entrance requirements, meter stack configurations, and metering CT requirements — directly from the utility rather than relying on design assumptions. This meeting identified the CT-metering discrepancy that saved $26,000. Also recommended early flood-proof vault design review with the structural engineer before the first permit submission.
Result
The project was awarded at $4.95M. Our estimate accuracy was 4.7% from final bid — the best of all 10 case studies. The FPL pre-bid meeting was credited by the GC as preventing a 3-week service approval delay. The contractor's project manager noted that the estimate's level of detail on the 17 different meter stack configurations saved 2 weeks of field verification time.