Why MLU updates matter for the takeoff
The MLU is not a price list. It is a table of labor hours per unit of installed work — 0.45 hours per duplex receptacle in a standard installation, 1.15 hours per 4' LED strip in a suspended ceiling, 0.12 hours per foot of 3/4" EMT in exposed conditions. Your estimating software translates those hours into dollars using your blended labor rate.
When NECA adjusts the base units, the ripple effect on a bid is large. A 5% increase in the base unit for a common assembly, applied across 800 devices, is 40+ labor hours. At $85 blended, that is $3,400. On your $425k bid, that is the difference between winning at cost and winning at margin.
The three categories that moved most in 2025
1. Suspended and elevated luminaire installation: +8-12%
The largest change. The 2025 MLU increased labor units for suspended luminaires (particularly 2x4 troffers in hard ceilings, linear strips above 10', and pendant fixtures in high-ceiling retail) by 8-12%. The rationale cited in the NECA release was observational field data showing that installation times had been trending up due to more complex integrations (emergency battery backups, occupancy sensors, controls wiring) that were not captured in older base units.
If you are pricing out a 60,000 SF big-box retail with 400 linear strip fixtures and your library is on 2022 MLU, you are under-labor by roughly 40-50 hours on just the lighting install.
2. Cable tray and busway: +6-9%
Cable tray labor units increased about 7% on average, with larger increases for larger tray sizes (18"+ wide saw the biggest bumps). Busway labor units moved up 9% on the larger ampacity frames. Why: the field data showed that large-tray and large-busway installs were consistently running longer than MLU predicted, often due to coordination with other trades in crowded plenums.
3. EV charging circuit assemblies: new base units, up 15-20% from prior guidance
EV charging didn't have a comprehensive set of base units in 2022 — contractors were building custom assemblies. The 2025 MLU added codified units for L2 chargers (40A / 50A circuits with load management), L3 chargers, and multi-port shared-circuit installations. The published numbers are 15-20% higher than the custom assemblies most shops were using. Expect this to push EV bid prices up across the industry.
"We spent two weeks auditing our assembly library against 2025 MLU. Found $45,000 of labor we were eating on active bids. That audit is now a standing quarterly task."
Marcus Chen, VP Estimating, Meridian Electric — Dallas, TX
Categories where labor held steady or decreased
- Receptacle roughin (standard 20A duplex): unchanged
- Branch circuit wiring in EMT: -1.5% (tools and methods slightly improved)
- Service entrance through 400A: unchanged
- Panel installation through 42-circuit: -2% (prefab and modular trends)
How to audit your assembly library
If you use Accubid or ConEst, both vendors have published 2025 MLU database updates. Run them in a test environment first. Some assembly IDs remap.
If you use an internal library or Excel-based assemblies:
- Export your current assemblies to CSV.
- Match each assembly ID to the 2025 NECA MLU table of labor units.
- For any delta above 3%, flag for review.
- Apply the update in phases: lighting first, then cable tray/busway, then EV/specialty. Don't blanket-update and regret it.
- Bid both old and new on one sample project to see the dollar impact before rolling out.
What about subjective field adjustments?
MLU is the baseline. Your shop's real productivity, adjusted for your foremen, your prefab capabilities, your apprentice ratio, is a multiplier on top of MLU. Some shops run at 0.85x MLU (above average productivity). Some run at 1.10x (below average). The 2025 MLU update changes the baseline, not the multiplier. If you know your shop runs at 0.92x MLU, that multiplier applies to the new baseline the same way it applied to the old.
Practical cadence
Labor unit audits should happen quarterly, not every 3 years. Between formal NECA updates, your shop's own job-cost back-to-bid data should inform rolling adjustments. If your 50 most recent electrical bids show you are running 7% over on rough-in labor, your assembly library needs a 7% adjustment — don't wait for NECA to tell you.