Hooking a generator to your house: hire for the transfer switch

What the state says

• Never power house wiring by plugging the generator into a wall outlet. DOH calls this "back feeding." (WA DOH)
• The only safe way to connect a generator to house wiring is a power transfer switch, installed by a qualified electrician. (WA DOH)
• Keep the generator at least 20 feet from buildings. (WA DOH)

The permit

• Washington requires an electrical work permit for electrical installations unless the work is on the rule's exempt list. (WAC 296-46B-901)
• For a premanufactured generator, installing the transfer switch, and the wiring between the generator, the switch and the control gear, is not exempt. (WAC 296-46B-925)
• L&I's homeowner guide lists generators with the work that needs a permit and inspection. Only a property owner or an electrical contractor can buy the permit. (L&I F500-078-000)
• Starting without a permit can bring a fine of up to $2,000. (L&I F500-078-000, read Oct 18, 2026)
• The inspection must be requested within three business days of finishing, or one business day after any part is energized, whichever comes first. (L&I F500-078-000)

In Seattle

• The City, not L&I, issues electrical permits here. SDCI says you need one any time wiring is connected to electrical equipment. (Seattle SDCI)
• Seattle City Light says transfer switches must be installed by a licensed electrician and approved by City Light. (Seattle City Light)

Who can install the switch

An electrical business needs an L&I electrical contractor license, and the person doing the wiring needs an L&I certificate of competency, or a trainee certificate with supervision. (RCW 19.28.041) (RCW 19.28.161)

The contractor posts a $4,000 bond. (RCW 19.28.041, read Oct 17, 2026) The statute and L&I's page set no liability insurance requirement. L&I encourages electrical contractors to carry it but keeps no records of it, so ask for a certificate. (L&I)

State law lets owners do electrical work on their own home, but the exemption does not cover the construction of a new building intended for rent, sale or lease, or property offered for sale within 12 months after obtaining it. One exception: an owner putting up a new residential building with up to four units for rent, sale or lease can still get the exemption with a signed affidavit saying they will do the work and live in one of the units as their principal residence. That exemption is allowed no more than once every 24 months. (RCW 19.28.261) For a transfer switch in Seattle, City Light still calls for a licensed electrician.

Questions for the electrician

1. What is your electrical contractor license number, and who will do the wiring?
2. Which circuits will the switch carry, and will the generator I own handle them?
3. Will you buy the electrical permit and book the inspection?
4. Will you get City Light's approval for the switch, and what do you need from me for it?
5. Where should the generator sit so it stays 20 feet from the house and the inlet still reaches?

During an outage

• Check L&I Verify before the electrician arrives.
• For a downed line, or a tree in the lines making them droop or spark, call 911 and stay at least 30 feet away. City Light's outage line is (206) 684-3000. (Seattle City Light)

Next

Read how to hire an emergency electrician in Seattle and what an electrician's license covers.