Tennessee
Solar Permit Plans.
NEC 2017. No Net Metering.
TVA Territory. 95 Counties.
Tennessee's state-minimum electrical code is still the 2017 NEC — adopted in 2018 and never updated, even after the State Fire Marshal's Office modernized the building, fire, and energy codes to 2021 editions in 2025. Layer on a federally owned utility that runs 153 separate local power companies, no statewide net metering law, and four cities — Nashville, Memphis, Knoxville, Chattanooga — that certify their own inspection programs, and Tennessee rewards installers who verify rather than assume. Every plan set we build starts with confirming which code edition and which utility actually apply.
A State That Modernized Its Building Codes and Left the Electrical Code Behind
Permit Design builds Tennessee solar permit plan sets for solar installers, EPCs, and roofing companies across all 95 counties. The state electrical code is the 2017 NEC (NFPA 70-2017) with Tennessee amendments, in effect since October 1, 2018 — and it did not move when the State Fire Marshal's Office updated building, fire, energy, and existing-building codes to 2021 ICC editions in 2025. Nashville, Memphis, Knoxville, and Chattanooga each run independent certified inspection programs that can enforce a newer NEC edition above that 2017 floor, so every Tennessee plan set confirms which edition the specific AHJ enforces before finalizing the rapid shutdown and wiring documentation.
Tennessee Valley Authority (TVA), federally owned since 1933, supplies wholesale power to 153 local power companies covering roughly 99.7% of the state. There is no statewide net metering law and no standardized interconnection rule — each LPC sets its own process. Every plan set confirms the correct NEC edition, structural code, and interconnection format for the specific AHJ and LPC serving the project address.
Last updated: June 2026 · Reading time: ~8 minutes · NEC 2017 state-minimum status, TVA interconnection structure, and local AHJ adoption confirmed as of June 2026.
Building Codes Modernized in 2025. The Electrical Code Didn't Move.
This is the single most overlooked fact in Tennessee solar permitting, and it's easy to miss because the rest of the state's code stack looks current.
In January 2025, the Tennessee State Fire Marshal's Office filed rules updating the state's minimum building, fire, energy conservation, and existing building codes to the 2021 ICC editions, effective April 17, 2025 (with a 120-day grace period to August 15, 2025; the IBC specifically became effective August 17, 2025). That rule package modernized five separate code chapters. The electrical code chapter — 0780-02-01, which adopts NFPA 70 — was not part of it. The currently published Tennessee State Fire Marshal adopted-codes list still shows the 2017 edition of the National Electrical Code, originally made effective October 1, 2018, with two Tennessee-specific carve-outs: Section 110.24 (Available Fault Current) is optional, and AFCI protection is optional in bathrooms, laundry areas, garages, unfinished basements, and circuits dedicated to refrigeration equipment.
NEC 2017 + IRC 2018 (Residential) + IBC 2021 (Commercial)
Three different code families govern a Tennessee solar permit, and they were not all updated at the same time. Confirming which edition the project's specific AHJ enforces is the first thing every Tennessee plan set needs to get right.
Structural loads vary across Tennessee's geography — East Tennessee's mountain terrain, the Cumberland Plateau, and West Tennessee's flatlands carry different ASCE 7 wind values. Permit Design calculates loads per project county rather than applying a statewide assumption.
A Federally Owned Utility, 153 Local Power Companies, and No Net Metering
Tennessee's utility structure looks nothing like most states', and it changes how every solar proposal should be sized. Here's what installers need to understand before quoting a Tennessee project.
TVA's prior Generation Partners/Green Power Providers program paid premium fixed rates for solar generation but closed to new applicants at the end of 2019. What exists now — Green Connect, Self-Generation, DPP — pays TVA's avoided-cost rate, which is lower and fluctuates monthly. Permit Design's documentation reflects the current program structure, not the pre-2019 economics.
153 Local Power Companies, One Wholesale Supplier
TVA supplies wholesale power to 153 local power companies (LPCs) — a mix of municipal utilities and electric cooperatives — covering roughly 99.7% of Tennessee. Each LPC administers its own interconnection process; there is no standardized statewide template. The five largest, plus the one Tennessee utility outside the TVA system, are below.
| Utility | Territory | Customers | Program Type | Notes |
|---|---|---|---|---|
| Nashville Electric Service (NES) | Davidson County + 6 surrounding counties | ~450,000 | Self-Generation / DPP, Green Connect, community solar | One of the 11 largest public power utilities in the US |
| Memphis Light, Gas & Water (MLGW) | Memphis / Shelby County | ~420,000 electric | Self-Generation / DPP — explicitly no net metering | Largest 3-service municipal utility in the US; all-requirements TVA contract |
| Middle Tennessee Electric (MTE) | Fast-growing Middle TN suburban counties | ~230,000 | Self-Generation / DPP via TVA framework | Tennessee's largest electric cooperative |
| Knoxville Utilities Board (KUB) | Knox County + surrounding area | ~210,000 | Self-Generation / DPP via TVA framework | One of TVA's oldest distribution partners, est. 1939 |
| EPB (Chattanooga) | Chattanooga / Hamilton County | ~180,000 | Self-Generation / DPP via TVA framework | Independent certified inspection program; muni fiber utility |
| Appalachian Power | Parts of northeast Tennessee | — | Standard IOU net metering (non-TVA) | Tennessee's one electric utility outside the TVA system; regulated by TPUC |
Appalachian Power serves pockets of northeast Tennessee near the Virginia border entirely outside the TVA wholesale system, regulated by the Tennessee Public Utility Commission. Standard investor-owned-utility net metering can apply there — installers near Bristol or Mountain City should confirm whether an address is TVA/LPC or Appalachian Power territory, since the program rules differ substantially just a few miles apart.
Tennessee Solar Permit Plan Set Contents
Every Tennessee plan set confirms the specific AHJ's enforced NEC edition, references the correct IRC 2018 or IBC 2021 structural provisions, documents the rapid shutdown configuration for that edition, and identifies the correct TVA local power company for the project address.
Also doing commercial rooftop, carport, or ground-mount in Tennessee?
Tennessee commercial solar structural packages reference the 2021 IBC — effective statewide August 17, 2025 — with NEC 2017 electrical (confirmed per AHJ) and TVA territory LPC interconnection across NES, MLGW, KUB, EPB, Middle Tennessee Electric, or any of the state's other 153 local power companies. Engineering available for flat-roof mechanically attached and ballasted arrays, carport canopy steel structures, and fixed-tilt or tracker ground-mount systems — including the TVA transmission-coordination requirement above 50 kW. Scope and turnaround quoted per job.
How Tennessee Solar Permit Plan Sets Work
Submit Your Tennessee Project
Tell us the county and city for the install. From there we identify whether the AHJ is one of Tennessee's four independently certified programs (Nashville, Memphis, Knoxville, Chattanooga) or follows the State Fire Marshal's 2017 NEC minimum, pin down the correct local power company, and determine whether IRC 2018 or IBC 2021 structural provisions apply.
We Build to the Confirmed Edition
NEC documentation matched to the edition the specific AHJ actually enforces — not assumed from the state minimum. IRC 2018 or IBC 2021 structural with county-specific ASCE 7 loads. Tennessee-licensed PE-stamped calculations. Interconnection package formatted for the correct LPC's process.
Delivered in 24–48 Hours
Turnaround for the full 7-sheet Tennessee package is 24–48 hours from submission. From there you can move on the building permit application, the electrical permit, and the LPC interconnection request in parallel. Free revisions until your Tennessee AHJ approves.
Try Us on Your First Tennessee Project. Free.
Haven't worked with us before? Send over the details of your first Tennessee residential project and we'll put together the full 7-sheet package at no cost — covering the confirmed NEC edition for your specific AHJ, IRC 2018 structural sign-off, region-appropriate loads, and the correct local power company identified for your project address.
⚠️ For licensed solar installers, EPCs, and roofing companies only. Individual homeowners and residential end customers are not eligible for this offer. One free plan set per company.
Tennessee Solar Permit Design — Frequently Asked Questions
Tennessee Solar by the Numbers
Top 3 Reasons Tennessee Solar Permits Get Rejected
Three permit rejection causes account for the majority of Tennessee solar project delays across the state's mix of State Fire Marshal jurisdictions and independently certified city programs. All three are avoidable with verification up front.
Tennessee Solar Permits —
Verified, Not Assumed.
NEC Edition Confirmed Per AHJ · IRC 2018 + IBC 2021
153 Local Power Companies · 95 Counties · 24–48 Hours