Case Study — Data Center
Data Center Shell & Core Electrical Estimate — Dallas, TX
Project Overview
Full electrical estimate for a 250,000 sq ft hyperscale data center shell and core project. Scope included: dual 15kV utility feeds from Oncor with (2) 5000A main-tie-main switchgear lineups, (24) 3000A PDU whips, (8) 2.5MW diesel generators with paralleling switchgear, (4) 750kVA UPS modules with battery banks (2N configuration), complete automatic fire suppression and VESDA system, and pre-action sprinkler monitoring. The estimate covered all electrical infrastructure up to the white space floor tile edge.
CSI MasterFormat Divisions Covered
26 05 00, 26 05 33, 26 08 00, 26 09 23, 26 12 00, 26 22 00, 26 24 00, 26 27 13, 26 32 00, 26 36 00, 26 43 13, 26 52 00, 27 05 00, 28 31 00, 28 33 00
Estimating Challenges
- 2N redundancy requirement doubled takeoff quantities for feeders, conduits, and distribution equipment — the PDU whip count alone required 24 individual feeder takeoffs through 8 separate cable tray routes
- Generator emissions compliance for Dallas/Fort Worth non-attainment area required selective catalytic reduction systems that were not specified in the initial RFP package — added $215,000 to the estimate
- Oncor transformer lead times were quoted at 38 weeks — the GC needed $1.2M in early procurement allowances before the full permit set was released
- Medium voltage termination labor was underestimated by the design team — (48) 15kV terminations required certified splice technicians at $165/hour per man, adding $38,000 to labor cost
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 the design included only (6) of the required (8) 2.5MW generator paralleling breakers — ($42,000) add
- Caught missing grounding electrode conductor connections for the (24) PDU whips — ($18,000) saved
- Flagged the fire alarm panel location as being in the generator exhaust pathway during an onsite review — relocation saved ($7,500) in rework
Labor Forecasting
Used NECA MLU data center factors with 15% productivity reduction for confined space work (cable tray installation above 14 feet, raised floor access constraints). Coordinated with the GC on a 6-day work week schedule with 10-hour shifts to accelerate the electrical program. Applied Dallas-specific prevailing wage rates with IBEW LU 20 classification. Budget included $64,000 in third-party testing and commissioning labor.
Material Escalation Strategy
Generator procurement was the highest risk category—8-month lead time with copper and steel content at 35% of generator cost. Recommended and the GC accepted a joint procurement strategy: FK Electrical Estimating prepared the detailed BOM (342 line items) for the generator paralleling switchgear 120 days before the main bid date. This allowed the contractor to obtain firm pricing on 64% of the total material value. The switchgear ultimately came in at quote + 3.2%.
Budget Comparison
| Line Item | Initial Estimate | Final Bid | Variance |
|---|---|---|---|
| Medium Voltage Switchgear | $1,840,000 | $1,912,000 | +3.9% |
| Generators & Paralleling | $2,310,000 | $2,431,000 | +5.2% |
| UPS & Battery Systems | $1,580,000 | $1,612,000 | +2.0% |
| PDU & Distribution | $1,220,000 | $1,269,000 | +4.0% |
| Cable Tray & Feeder | $680,000 | $724,000 | +6.5% |
| Labor & Commissioning | $1,070,000 | $1,134,000 | +6.0% |
| Total | $8,050,000 | $8,632,000 | +7.2% |
Risk Mitigation
Recommended the GC establish a dedicated data center commissioning coordinator role separate from the electrical superintendent. Prepared a 47-line-item long-lead procurement schedule with latest order dates for each equipment category. Flagged that the Oncor utility transformer vault needed fire-rated construction per Dallas amendment to the IBC — the design showed standard CMU construction. This saved $23,000 in potential post-build retrofitting.
Result
The contractor was shortlisted to three bidders and ultimately awarded the project at $8.45M. Our estimate was within 2.9% of the final awarded subcontract value. The pre-procurement strategy on generator paralleling switchgear saved an estimated $240,000 compared to market pricing at time of award.