Transfer switch cost installed: interlock, ten circuits, or 200 amps

The generator is the engine in the yard. The transfer switch is the box that keeps that engine off the utility lines. If both are tied together, you can push power back onto the street and shock a lineman who thinks the wire is dead.

You are not shopping for one part called “hookup.” You are shopping for one of three jobs, and quotes mash the names on purpose.

An interlock is a sliding plate on the breaker panel that makes it physically impossible to turn the generator breaker on while the main is on. A manual transfer switch moves a short list of circuits, or a handle, after you start a portable. An automatic transfer switch watches the street, starts a compatible standby, and moves the house (or a subpanel) without you in the basement.

Automatic vs manual is that fork. Whole-home vs essential-only is how much of the house stays on. The leftover question is what you pay for the switch itself.

HomeGuide puts a generator transfer switch, unit plus labor, at $400 to $2,500. Manual is $400 to $1,300 installed. Automatic is $600 to $2,500 installed. An interlock kit is $400 to $850 installed.

HomeGuide: generator transfer switch installation cost

Angi’s 2026 survey of typical professional jobs lands tighter: $1,200 to $1,600, average $1,450, with the same automatic $600 to $2,500 and manual $400 to $1,300 bands.

Angi: cost to install a generator transfer switch

Those are other people’s panels. A 200-amp service-entrance ATS on a packed box will sit above the average. A six-circuit manual switch next to an inlet you already have is the bottom. The generator is a separate pile of money. Do not compare an ATS bundled into a standby quote against a $500 interlock on a portable you already own.

Three envelopes that all say “transfer switch”

Bid A, interlock on the panel you have. HomeGuide $400 to $850 installed. Kit $50 to $150, supplies $200 to $400, labor $150 to $300. You still need a legal inlet, not a cord in a dryer outlet. You still turn the main off, slide the plate, then turn the generator breaker on. Interlock vs transfer switch is whether your inspector even allows that plate. Inlet box done right is the outdoor plug.

Bid B, six- to ten-circuit manual switch. HomeGuide unit prices: 6-circuit $230 to $360, 10-circuit $300 to $670, installed manual job $400 to $1,300. The electrician moves selected breakers into a small extra panel or into the switch. Fridge, a lighting circuit, furnace or boiler controls, maybe a sump or a well. The rest of the house stays dark. Critical-load panel is that list. Count a 240-volt breaker as two slots, because it takes two poles.

Bid C, automatic at service size. HomeGuide automatic $600 to $2,500 installed, unit $400 to $2,000. A 200-amp switch that can feed the whole panel is the whole-home product. A 100-amp ATS on a 200-amp house is not whole-home. It is a limited feed with better marketing. HomeGuide’s amp table puts a 200-amp unit at $680 to $1,500 before labor. Installation still adds $200 to $500 on a simple job, more when the panel is a mess.

If the bid just says “transfer switch, $2,000” with no automatic or manual, no amp rating, and no circuit count, you do not know what you bought.

What the line items actually are

Ask them to split the box, the inlet, the labor, and the permit, because a bundled “hookup” hides the expensive part.

HomeGuide’s breakdown: switch $200 to $2,000, labor $200 to $500 on a straightforward install, inlet box $20 to $100, heavy cord $30 to $350. Kits that include the switch, inlet, and cord run $300 to $500 for smaller amperage models. Electricians $50 to $130 an hour, plus a $75 call-out, and 2 to 4+ hours.

Angi is in the same labor neighborhood: $50 to $100 an hour, 2 to 4 hours for a basic job ($200 to $500), $500 to $1,500 when the panel fights. Permits $50 to $350 on both pages.

The extras are how a $1,200 switch becomes a $4,000 afternoon. HomeGuide: new panel $850 to $2,500, subpanel $500 to $1,700. Angi: panel replacement $520 to $2,100, subpanel $400 to $1,750, extra breakers $100 to $200 each. If the box is full, you are buying a subpanel before anyone hangs the switch.

Wiring a whole-house standby is not this page. HomeGuide puts labor alone to wire a generator to a house at $3,000 to $5,000 when you are installing the engine too. That pad, gas line, and 200-amp ATS live on sizing a standby and whole-home vs essential-only.

When is the cheap plate the wrong product?

Ask whether you will be home in the dark, because an interlock and a manual switch both need a person.

If you travel, if someone in the house needs power without a scavenger hunt, or if the generator sits in a drift of snow, automatic is the product. It only works with a standby the switch can start: start wires, a battery, usually a matching brand. “ATS-ready” on a portable brochure is not that.

If outages are rare and you already own a portable, Bid A or Bid B is the honest envelope. You still need the inlet, the cord, and a place outdoors that does not kill you with exhaust. Generator placement is that pad.

If the last storm made you want upstairs lights, the dryer, and the AC the whole time, a 10-circuit manual switch will feel like a flashlight with extra steps. You wanted Bid C, and you wanted an engine that can take the surge.

Do not let anyone sell an interlock as “whole home” because it sits on the main panel. The plate does not make the portable big enough. HomeGuide is blunt: turn off circuits before you slide it, because most portables cannot support the whole house at once.

What usually blows the number

Ask who pays if the panel is full, because that is the change order.

A packed 1970s box with no space for a generator breaker is a subpanel job first. A 200-amp ATS that needs a new service-entrance tap is a different license than hanging a 10-circuit kit next to the laundry.

Long conduit from a standby pad, a panel in a crawl, or an inlet on the far side of the house is why Angi puts complex labor at $500 to $1,500. HomeGuide’s “60 to 70 feet” from generator to switch is a planning range, not a promise your 100-foot run is free.

A permit skipped so the job stays cheap is how you fail inspection, or how the insurance conversation goes badly after a fire. Most towns treat this as electrical work. Hire the license, not a weekend YouTube.

Backfeeding a dryer outlet is not a savings line. It is the lineman problem, and it is illegal in a lot of places. If the quote has no inlet and no interlock and no transfer switch, it is not a legal hookup.

What has to be on the bid before anyone opens the panel

Ask automatic or manual, in those words, with the amp rating and the circuit count.

Ask whether the switch matches the generator, or the service, and say which. A 30-amp manual switch on a 7,500-watt portable is Bid B. A 200-amp ATS on a 22 kW standby is Bid C. Mixing those on one line is how people pay twice.

Ask for the inlet location, the cord included or not, and who pulls the permit.

Ask what happens if the panel is full. Subpanel as a line, or “if needed” as a blank check.

Ask which circuits move, with names, not “essentials.” Fridge is not the same slot as a well.

A finished scope looks like this: interlock, manual, or automatic; amps; circuit count or whole-panel; inlet yes or no; permit included; panel or subpanel work priced; generator separate. If they cannot fill those, wait on the cover coming off.

How do I decide this week?

Price an interlock, a 10-circuit manual switch, and a service-size automatic on the same panel, and make each bid name the inlet and the permit.

Walk the last outage you sat through and pick the rooms that have to stay on, because that list is the switch, not the engine.

Refuse a number that says “transfer switch” with no automatic or manual and no amp rating.

Keep automatic vs manual and whole-home vs essential-only on the same table as this invoice. Hire the install that names the plate, the ten circuits, or the 200-amp box, before anyone starts the generator.