Questions to bring to a licensed electrician about backup circuits

A good quote starts with a good brief. The more you bring, the less the electrician has to guess, and the less your quote will change later.

Bring this

• Your loads list, sorted into must, nice and can wait.
• Label photos for the big loads, (see appliance labels).
• A note of anything you plan to add in the next few years, such as an EV charger or a heat pump.
• Your recent utility bills, if they help show how much you use.
• The manual or model name for any battery or generator you're already considering.
• A photo of your main panel with the door open. Don't remove the cover.

Questions about scope

Whole-home or partial? Ask which one they'd suggest for your list and why. Wikipedia notes that "A transfer switch can be set up to provide power only to critical circuits or to entire electrical subpanels."¹ Both exist, so ask which fits. The difference between them is a good place to start the talk.

Which circuits move? Ask for a written list of circuits that will be on the backup side, and which will be off.

What about the big loads? Ask what happens with the well pump, heat pump, oven and any EV charger. See big loads.

Questions about equipment

• Is a separate panel for chosen circuits needed, or can the switch work another way?
• Which kind of transfer switch is it, and does it switch automatically?
• Is it sized from the maker's installation guide? Manufacturers "can provide installation guides."¹ Ask to see the guide for your product.
• What happens if the load is bigger than the system can carry?
• Can I add circuits later?

Questions about rules and paperwork

• Is a permit needed, and who applies for it? Rules differ widely, and some places require licensed contractors.²
• Will an inspection follow, and when?
• Does the electric utility need to be told or to approve the work? Ask the utility as well.
• Are there rebates or incentives? Don't take a number on trust. Ask for the official program page for your state or country.
• Is the electrician licensed for this work where you live, and can you see the license number?

Questions about the day it goes live

• How do I shut the backup system off, and where is the shutoff?
• How will the panel be labeled?
• What do I do in an outage, step by step? Ask for it in writing, from the maker's manual.
• Who do I call if something trips?

Quotes

Get the scope in writing. Make sure it names the circuits, the equipment, the permit and who is responsible for the final inspection. If two quotes cover different circuits, they aren't comparable yet. Make them cover the same list first.

Take your time. A day to read a quote beats a year of regret.