Electrical Contractors and Other Wiring Installation Contractors (NAICS 23821)

A Histometrics industry primer for public-market and private investors

Short page — single-child pass-through. In the North American Industry Classification System (NAICS, the U.S. government's standard framework for classifying businesses), the 5-digit industry 23821 contains exactly one 6-digit national industry: 238210, of the same name. The two levels cover the same firms, the same revenue, and the same activity. This page gives the level's own ground-truth federal figures and a brief orientation; for the full treatment — value chain, the investable universe in detail, unit economics, demand drivers, regulation, and consolidation — see the child primer, NAICS 238210.

1. Overview

Electrical contractors are the firms that install and service the wiring, power distribution, lighting, controls, and low-voltage systems in and around buildings and other structures — parts and labor, new installs, retrofits, and ongoing service. [4] This is a large, fragmented, labor-intensive service trade that sits directly in the path of three of the biggest capital-spending waves in the economy: the data-center/AI buildout, electrification (electric vehicles, heat pumps, all-electric buildings), and factory reshoring. U.S. electricity demand is rising for the first time in a generation, and almost none of the new load gets connected without an electrical contractor. [7][8][9]

Because the 5-digit level and its one child are effectively identical, everything below is a condensed rollup; the detail lives in the 238210 primer.

2. What's inside — and why this level equals its one child

NAICS is a nested hierarchy: each 5-digit industry subdivides into one or more 6-digit national industries. When there is nothing further to subdivide, the U.S. simply repeats the parent as a single child with a trailing "0." That is the case here:

With a single child, 23821 = 238210: same scope, same establishments, same receipts. The scope covers building power and lighting; airport, highway, and traffic lighting; fiber-optic and premises/network cabling (inside the building, not long-haul line); fire- and security-alarm systems; home automation; cable-TV hookups; and increasingly solar, battery-storage, and electric-vehicle-charging installation. It excludes the utility poles, transmission/distribution lines, and substations that move power between the grid and a building (NAICS 237130), the mechanical/plumbing trades (238220), and the utilities themselves (industry group 2211). [4] Those boundaries matter for the investable universe — see the child primer.

3. How big it is (this level's rollup figures)

Ground-truth U.S. federal statistics for NAICS 23821, from the Histometrics ground-truth dataset (dollar figures converted from thousands):

Concentration — barely any. The four largest firms hold just 4.8% of receipts (the four-firm concentration ratio, CR4); the top 8 hold 7.8%, the top 20 hold 12.6%, and the top 50 combined hold only 19.1%. [2] The Herfindahl-Hirschman Index (HHI — a standard concentration gauge where 10,000 is a pure monopoly and anything under 1,500 is "unconcentrated") is just 11.6. [2] In plain terms this is one of the most fragmented industries in the U.S. economy: no firm has anything close to national pricing power, and competition is fought locally, job by job.

Undercount caveat. These figures count employer businesses only — firms with payroll. This trade has a very large tail of self-employed, owner-operator electricians and no-payroll micro-outfits. The Census Bureau publishes those separately as "nonemployer" businesses; our ground-truth file does not include that count, so we put no number on it. [1][2] The practical effect: the true number of operating electrical businesses is meaningfully higher than the ~79,000 employer firms shown, though those micro-operators add relatively little to the revenue and payroll totals. The data capture the industry's economic weight well but undercount the sheer number of small operators. (Because 4-firm concentration is so low, the industry is dominated by small and individual ownership — reinforcing the same caveat.)

4. The investable universe (where value concentrates across the children)

With only one child, value concentrates exactly where it does in 238210. Because the industry is so fragmented, there are few pure public plays, and the largest listed "electrical" names are diversified — several earn much of their revenue in utility-line construction (237130) or mechanical/HVAC trades (238220), not premises wiring. The cleaner public proxies for this level are IES Holdings (NASDAQ: IESC) and MYR Group (NASDAQ: MYRG), with EMCOR Group's (NYSE: EME) electrical construction segment and the fast-growing electrical arm of Comfort Systems USA (NYSE: FIX) also relevant; Quanta Services (NYSE: PWR), MasTec (NYSE: MTZ), Dycom (NYSE: DY), and Primoris (NYSE: PRIM) carry heavy utility-line overlap. There is no pure electrical-contracting exchange-traded fund (ETF); the Global X U.S. Infrastructure Development ETF (ticker PAVE) holds several of these together. The larger universe is private — employee-owned and private-equity-backed platforms such as Rosendin, Faith Technologies, and ArchKey Solutions. The full table, with market caps, revenue, and the 238210-purity note for each name, is in the child primer.

5. How the money works

An electrical contractor earns the spread between what it bills and what it costs to put labor and materials in place; the game is estimating accuracy, labor productivity, and mix. Specialty subcontractors typically run gross margins of roughly 26–34% on project work but thin net margins of ~5–10% (2.5–6% at smaller shops), with recurring service and maintenance carrying the highest margins (~45–55% gross). [15] Fixed-price (lump-sum) work bears most of the overrun risk; a bid struck at 28% can close well below 19% if labor, materials, or scope move against it. [15] The metrics owners and investors watch — backlog and book-to-bill, billable field hours, service-vs-project mix, change orders and "margin fade," and working capital (including retainage held back until a job finishes) — are laid out in full in the 238210 primer. [18]

6. What drives demand

Demand tracks construction and, increasingly, electricity itself. The dominant near-term driver is data centers / AI: from early 2024 through late 2025, data centers accounted for over 70% of the increase in private nonresidential construction spending, and one forecast sees U.S. data-center power demand climbing from ~24 gigawatts (GW) toward 110 GW by 2030. [7] Layered on top are grid modernization and load growth [10], domestic manufacturing / reshoring of semiconductor and battery plants [9], electrification and clean energy (EV charging, heat pumps, solar, storage), new construction and renovation (interest-rate-sensitive), and the industry's most stable slice, recurring service and emergency restoration. [18] See the child primer for the detail and sourcing.

7. Regulation

Electrical work is regulated mainly at the state and local level, which is part of why the industry stays fragmented. Most jurisdictions license electricians (apprentice → journeyman → master) and require a contractor to hold or employ a licensed master; work must meet the National Electrical Code (NEC), published as NFPA 70 by the National Fire Protection Association, and pass municipal inspection. [5][12] The Occupational Safety and Health Administration (OSHA) governs jobsite electrical safety under 29 Code of Federal Regulations (CFR) Part 1926, Subpart K. [11] Federal public-works rules — Davis-Bacon prevailing wages and surety bonding — apply to covered contracts, and union (International Brotherhood of Electrical Workers / National Electrical Contractors Association) versus merit-shop status shapes labor cost. [13][14] Full detail is in the 238210 primer.

8. Consolidation

Consolidation is the industry's defining trend, and the federal concentration figures above (CR4 of 4.8%, HHI of 11.6) are from 2022 and predate several large deals. Private equity now drives roughly 75% of electrical-contractor mergers and acquisitions (M&A), typically forming a "platform" and bolting on local shops; electrical deals have fetched 15–20% higher multiples than other specialty-contractor deals, with typical enterprise values around 6–8× EBITDA (earnings before interest, taxes, depreciation, and amortization). [16][17] Strategic buyers are active too — Quanta bought Cupertino Electric for ~$1.54 billion (2024) and EMCOR bought Miller Electric for ~$876.8 million (2025). [17][18] Drivers, deal counts, and the full deal log are in the child primer.

9. Risks

The binding constraint is labor — a persistent shortage of licensed electricians, foremen, and estimators caps how much work the industry can take on and pushes up wages. [5] Other principal risks: fixed-price cost overruns [15][18]; cyclicality and interest rates on construction volumes; materials and supply chains (copper, switchgear, transformers, tariffs) [18]; working-capital and credit strain from retainage and disputed change orders [18]; bonding, insurance, and litigation exposure; customer/project concentration for firms leaning hard into hyperscale data centers; and demand overbuild if the data-center/AI capital cycle cools faster than expected. Each is developed in the 238210 primer.

10. How to invest, and the outlook

Public-market routes are limited to the diversified names in Section 4 and are best treated as different exposure profiles, not interchangeable peers — examine each company's segment mix, backlog quality, fixed-price exposure, cash conversion, and data-center concentration before applying price-to-earnings or enterprise-value-to-EBITDA multiples; a broad infrastructure ETF such as PAVE offers a diversified, lower-single-name-risk approach. Private-market routes are the more natural fit for most of this industry: own or operate a local contractor, buy one from a retiring owner, back a private-equity roll-up, provide private credit against backlog and receivables, or finance an employee-ownership (ESOP) transition.

Outlook. The demand backdrop is the strongest in a generation — data centers, electrification, reshoring, and grid investment all pull in the same direction, and rising electricity demand is a structural, multi-year tailwind rather than a one-cycle spike. [5][8][9] The primary constraints are skilled-labor supply and interest-rate-sensitive construction volumes; the primary risk is a faster-than-expected cooling of the data-center/AI capital cycle. For patient investors, the more durable value may lie in the fragmented private middle market — recurring service, disciplined estimating, and consolidation economics compounding quietly — rather than in the handful of already richly valued public names. The full outlook and investment discussion are in the child primer, NAICS 238210.

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Sources

This is a rollup page; sources are a subset of the child primer's, with numbering preserved for cross-reference.

1. U.S. Census Bureau, County Business Patterns (CBP), 2023 — NAICS 238210 establishments, employment, and payroll (via Histometrics ground-truth dataset). https://www.census.gov/data/datasets/2023/econ/cbp/2023-cbp.html
2. U.S. Census Bureau, 2022 Economic Census — Concentration of Largest Firms for the U.S., NAICS 238210 (receipts, firm count, CR4/CR8/CR20/CR50, HHI). https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN?codeset=naics~238210
3. U.S. Census Bureau, 2022 NAICS: 238210 — Electrical Contractors and Other Wiring Installation Contractors (definition and exclusions). https://www.census.gov/naics/?details=238210&input=238210&year=2022
4. U.S. Bureau of Labor Statistics, Occupational Outlook Handbook: Electricians, 2025. https://www.bls.gov/ooh/construction-and-extraction/electricians.htm
5. Grid Strategies LLC, National Load Growth Report 2025 (data-center-led power demand; ~24 GW→110 GW; >70% of the rise in private nonresidential construction spending). https://gridstrategiesllc.com/wp-content/uploads/Grid-Strategies-National-Load-Growth-Report-2025.pdf
6. Lawrence Berkeley National Laboratory, United States Data Center Energy Usage Report: 2025 Update. https://eta-publications.lbl.gov/publications/united-states-data-center-energy-2025
7. U.S. Energy Information Administration, Short-Term Energy Outlook / electricity-demand release. https://www.eia.gov/pressroom/releases/press582.php
8. U.S. Department of Energy, National Transmission Needs Study, 2023. https://www.energy.gov/sites/default/files/2023-12/National%20Transmission%20Needs%20Study%20-%20Final_2023.12.1.pdf
9. Occupational Safety and Health Administration, 29 CFR 1926 Subpart K — Electrical. https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926SubpartK
10. National Fire Protection Association, NFPA 70: National Electrical Code (NEC). https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70
11. Acquisition.gov, FAR Subpart 22.4 — Labor Standards for Contracts Involving Construction (Davis-Bacon). https://www.acquisition.gov/far/subpart-22.4
12. Acquisition.gov, FAR Subpart 28.1 — Bonds and Other Financial Protections. https://www.acquisition.gov/far/subpart-28.1
13. Profitability Partners / Lightning Path Partners, Electrical Contractor Profit Margins, 2025–2026. https://profitabilitypartners.io/electrical-contractor-profit-margins/
14. Cascade Partners, Electrical Contracting and Utility Infrastructure M&A Update (H2 2025), 2026; and EC&M, "Electrical Contractor M&A Dips in 2025," 2025. https://cascade-partners.com/wp-content/uploads/2026/02/Electrical-Contracting-and-Utility-Infrastructure-MA-Update-H2-2025-vF.pdf
15. BMI Mergers & Acquisitions, Electrifying M&A Market for Electrical Contractors: 2024 Recap (~6–8× EBITDA multiples), 2025. https://www.bmimergers.com/2025/02/19/electrical-contractors-2024-recap/
16. Company SEC filings and FY results — Quanta (PWR), EMCOR (EME), Comfort Systems USA (FIX), MasTec (MTZ), Dycom (DY), IES Holdings (IESC), MYR Group (MYRG), Primoris (PRIM). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=pwr&type=10-K
17. Quanta Services, Quanta Services Acquires Cupertino Electric (~$1.54 billion), 2024. https://investors.quantaservices.com/news-events/press-releases/detail/360/quanta-services-acquires-cupertino-electric-inc-a-premier-electrical-infrastructure-solutions-provider-to-the-technology-and-renewable-energy-industries
18. EMCOR Group, 2025 Form 10-K / acquisition of Miller Electric (~$876.8 million), 2026. https://www.sec.gov/Archives/edgar/data/105634/000010563426000025/eme-20251231.htm