Why backup panels and transfer switches are licensed electrician work

No. Installing a backup panel or a transfer switch is licensed electrician work. It involves your home's main service, and a mistake can hurt you, a neighbor or someone working on the power lines.

This site doesn't give wiring steps for these jobs, and it won't. What it can do is explain why.

The panel is live

Main panels carry mains-voltage power from the utility. With the cover off, "American panelboards commonly have some live parts exposed."¹

That's why this work is not a place to learn as you go. Even a careful home owner can touch something live without meaning to. A backup system adds a second source of power to the same wiring, which makes it more complicated still.

Mistakes reach beyond your house

A backup source wired to the home without a proper way to disconnect the grid is dangerous to people outside it. Utility workers expect the lines to be dead. The people at risk are linemen who believe a line is off. The transfer switch page explains how a switch prevents it.

Rules and permits

Many places require a permit and an inspection for this kind of wiring, and some limit who may do it. One US example is a city that "requires all installation work to be done by licensed contractors."² Rules vary by country, state and town. They may also change.

Your local building or electrical inspection office is the place to check. The right body depends on your country, state and town. Ask your electrician which permits apply.

Sizing and settings

A switch has to suit the circuits it controls. Makers of transfer switches "can provide installation guides to select the size of switch."³ The installation guide for your product is written for a qualified installer. Follow it, and follow the maker's manual for your own model.

What you can do yourself

Quite a lot, actually, and none of it involves tools.

• Write a loads list.
• Collect appliance details using the label guide.
• Note which big appliances you'd like on or off the backup circuits.
• Take your questions to a licensed electrician.

If you're unsure

Ask. A good electrician expects questions and will explain the plan in plain words. If a quote doesn't say which circuits move, or leaves out the permit, ask them to add it in writing before you agree. If you still feel unsure, get a second quote from another licensed electrician. Nobody should rush you into this job.

What not to do

• Don't open the main panel to move breakers.
• Don't connect a generator or battery to a wall outlet to feed the house.
• Don't change the wiring of a hard-wired battery system.
• Don't build or alter battery cells or packs.