What generator installation costs
Published national cost-guide estimates (2025–2026), not quotes. Quotes come from independent contractors, not this site.
| Job | Typical range | Source |
|---|
| Generator interlock kit, installed | $400–$850 | HomeGuide |
| Manual transfer switch | $400–$1,300 | HomeGuide |
| Standby generator, installed | about $8,000–$16,000 | manufacturer guidance via retailer |
| Montana state electrical permit (outside Bozeman, Belgrade, Manhattan) | $45 one added circuit · $70 for 2–3 · $120 remodel with panel/service change | Montana DLI form, Rev. 11/25 |
City permit fees are set by the city; ask the contractor or the city building division. Fuel lines, pad work and panel changes add to the total. See the Bozeman electrician cost guide.
Montana rules box
Montana requires electricians and electrical contractors to be licensed by the State Electrical Board (MCA Title 37, ch. 68). Look up any contractor or electrician by name or license number in the Montana DLI license lookup, and ask to see the license; electricians must carry it on the job. The board requires contractors to carry workers' comp and unemployment insurance coverage (or an exemption), not a set liability amount, so ask for a certificate of liability insurance too.
Bozeman, Belgrade and Manhattan issue electrical permits inside city limits; everywhere else in the valley, including Livingston, Three Forks, Big Sky and Four Corners, permits come from the Montana Department of Labor & Industry (DLI electrical permits). NorthWestern won't energize new or changed wiring without a permit. Montana adopted the 2023 NEC statewide effective September 26, 2026; certified cities enforce their adopted codes.
Montana's homeowner exemption (MCA 37-68-103(3)) covers work you do yourself on your own home kept for your own use, with a permit and inspection. It does not cover rentals, tenants or work on a grid-tied generator. Leave the meter, mast and utility side to licensed electricians and NorthWestern.
Questions to ask before you hire
- What is your Montana license number, and whose name is it under?
- Can you send a certificate of liability insurance?
- Can I have a written, itemized quote that lists the generator or switch model, which circuits it covers, the inlet, fuel work by others and the permit?
- Is there a trip or diagnostic fee, and is it credited if I hire you?
- What is your after-hours or weekend rate, if the job runs late?
- Who pulls the permit, and is it a city or a state permit at my address?
- Does this job need any NorthWestern service work, and are those charges in your quote or billed separately?
Don't pay the full price before the work is done. If a salesperson signs you up in your home, Montana gives a 3-business-day right to cancel many in-home sales (MCA 30-14-504); ask whether it applies to your contract. For more on vetting, read why a local contractor matters.