Disclosure: I earn a commission if you buy through links on this page, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Here's how I review generators.
Westinghouse WATS200 Review: Makes Your Portable Generator Act Like a Standby
By Justin · Updated September 25, 2026
With a normal manual transfer switch, you're the automatic part. The power goes out, and you go outside in the dark, wheel the generator out, plug in the cord, start it, and flip the switch. The Westinghouse WATS200 does all of that for you. When the utility power drops, it tells a compatible Westinghouse generator to start, switches your house over, and shuts the generator down again when the power comes back.
That's most of what a home standby generator does, at a fraction of the cost. It does come with a few conditions, and they matter.
Buy it if you already own (or are buying) a compatible Westinghouse generator with an ST/Smart Switch Ready outlet, and you want backup that works even when you're not home, like when you're traveling or when a storm hits at 2 a.m.
Skip it if your generator isn't a compatible Westinghouse, you can't leave the generator parked outside and hooked up, or a manual switch or interlock is fine for you. Those cost much less.
Check current price of the Westinghouse 200A transfer switch on Amazon
WATS200 Specs at a Glance
| Spec | Westinghouse WATS200 |
|---|---|
| Rating | 200A continuous, 120/240V, single phase |
| Service entrance rated | Yes |
| Enclosure | NEMA 3R aluminum (indoor or outdoor) |
| Transfer type | Automatic, open transition |
| Load management | Built in, handles up to 4 air conditioner loads |
| Generator control | Auto start and stop through the generator's Smart Switch Ready (ST) outlet. Keeps the generator battery charged |
| In the box | Transfer switch, 25 ft ST control cable |
| Sold separately | Generator, power cord, power inlet box |
| Listing | ETL listed to UL 1008 |
| Size / weight | 27.75" × 15.6" × 7.75", about 29.5 lbs |
| Warranty | 5 years limited |
| Installation | Licensed electrician required |
Specs from Westinghouse's WATS200 product page. Confirm the model number on the Amazon listing matches before you buy.
How It Works
- Your generator stays parked outside in its running spot, connected to a power inlet box with a power cord, and to the switch with the ST control cable.
- The utility power goes out. The switch notices and signals the generator to start.
- Once the generator is running, the switch moves your house over to generator power. The load management keeps up to four AC units from overloading it.
- When the utility power comes back, the switch moves the house back and tells the generator to shut down. It keeps the generator's battery charged while it waits for the next outage.
What I Like
It works when you're not home
This is the real reason to buy it. A manual switch is useless if the power goes out while you're at work or away for the weekend. With the WATS200, the sump pump keeps running, the freezer stays cold, and the pipes don't freeze, whether anyone's home or not.
It's a 200A service entrance switch
Being service entrance rated means it can go between your meter and your main panel, so it switches the whole house instead of a handful of circuits in a sub-panel. That makes installation simpler for many houses. Your electrician will know whether that's the right setup for yours.
AC load management is built in
A whole-house switch plus a portable generator could be a recipe for overloads, because the generator can't run everything a 200A panel can draw. The WATS200 manages up to four air conditioner loads, so the compressor doesn't try to start while the generator is already near its limit. That's usually the load that trips a portable generator.
It pairs with generators people actually own
Westinghouse lists more than 30 compatible models, going back to 2017. That includes every Westinghouse generator reviewed here: the WGen9500DF, WGen10500DFc, WGen11500DFc, and WGen11500TFc. The tri-fuel 11500TFc on natural gas is the best match of all. It auto-starts and runs on your gas line, so you don't have to refuel.
The warranty
Five years, longer than the generators themselves. That's reassuring for something that sits between your meter and your panel.
What I Don't Like
It only works with Westinghouse generators that have the ST outlet
The switch talks to the generator through Westinghouse's Smart Switch Ready outlet. No ST outlet, no automatic start. If you own a Champion, a Generac portable, or an Oxseryn, this isn't the switch for you. A few smaller Westinghouse models (the WGen5300 series and WGen6000DFc EFI) only work with it in 240V mode.
The generator has to live outside, ready to go
Automatic start only works if the generator is already sitting in its running spot, plugged in, with fuel in the tank or connected to propane or natural gas. That means it spends a lot of time outdoors. Plan for:
- A spot at least 20 feet from doors, windows and vents, since it can start without anyone watching
- A cover or enclosure rated for running, not just storage
- Fresh fuel: stabilized gas, or better, propane or natural gas
- Theft (a cable lock or chain doesn't hurt)
The real cost is more than the switch
The box includes the switch and the control cable. You'll also need a power inlet box, a generator power cord, and a licensed electrician (plus a permit in most areas). Installation costs vary a lot depending on your panel and local code. Get quotes before you decide it's cheaper than a standby generator.
It doesn't manage everything
Load management covers AC units only. A 200A house can still draw far more than any portable generator makes, so you'll still need to keep the electric water heater, dryer, oven and similar loads off during an outage, or have your electrician put those circuits on separate control.
What It Can Power
The switch itself is rated for 200 amps, but your generator sets the real limit. A WGen11500DFc puts out about 48 amps at 240V. That's plenty for central AC (managed by the switch), the fridge, freezer, sump and well pump, lights, and the furnace, but not the water heater and dryer at the same time. The generator reviews on this site have load tables for each size.
WATS200 vs a Manual Transfer Switch or Interlock
| WATS200 automatic | Manual switch / interlock | |
|---|---|---|
| Works when you're away | Yes | No |
| Starts the generator | Automatically | You do |
| AC load management | Up to 4 AC loads | No (you manage loads) |
| Generator compatibility | Westinghouse with ST outlet | Almost any generator with a 30A/50A outlet |
| Generator stored | Outside, connected | Anywhere, rolled out when needed |
| Cost | Higher | Much lower |
Questions People Ask
Will the WATS200 work with my generator?
Only if it's a Westinghouse with a Smart Switch Ready (ST) outlet. Westinghouse publishes the compatible model list on the product page. It includes the WGen9500, 10500, 11500, 12000, 14500 and 20000 series plus several iGen inverter models.
Does it come with the inlet box and cord?
No. You get the switch and a 25-foot control cable. The power inlet box and generator cord are sold separately.
Can I install it myself?
No. Westinghouse requires a qualified electrician, and most areas require a permit. It connects to your service entrance, so this isn't a DIY job.
Does it make a portable generator as good as a standby generator?
It gets you the automatic part. The differences are that you'll need to keep fuel ready (unless you're on natural gas), the generator lives outside under a cover, and a portable makes less power than most standby units.
How I Put This Review Together
I haven't installed this switch myself. This review is based on Westinghouse's published specs and compatibility list, and on how it fits with the generators reviewed on this site.
Bottom Line
If you have a compatible Westinghouse generator and want it to take care of outages without you, the WATS200 is the missing piece. The AC load management and 5-year warranty make it better than a basic automatic switch. Just budget for the inlet, cord and electrician, and plan a safe, covered spot where the generator can stay parked and ready.
See the Westinghouse 200A automatic transfer switch on Amazon