You added an inverter to your RV so you could run the microwave or the coffee maker off the batteries. Now you have a problem: your wall outlets are wired to the breaker panel, and the breaker panel is fed by the shore power cord. How do you get inverter power to those same outlets without running extension cords across the floor, and without ever having the inverter and the campground pedestal both pushing power into the same wires?
That is the whole job of an automatic transfer switch. This guide explains what it does, when you need one (and when you don't), and how to pick the right size. It is simpler than it sounds.
What a transfer switch actually does
An automatic transfer switch is a relay that sits between two AC power sources and your breaker panel. It only ever connects one source at a time.
- Plugged in at a campground or running a generator: the switch passes that power straight through to your panel. Everything works exactly as it does today.
- Unplugged: the switch senses that shore power is gone and automatically connects your inverter output to the panel instead. Your outlets, microwave, and TV keep working, now running off the batteries.
Because the two sources can never be connected at the same time, there is no risk of back-feeding the inverter from the pedestal or sending inverter power up the shore cord. It happens automatically. No switches to flip, nothing to remember.
Do you even need one?
Check this first, because a lot of people buy a transfer switch they don't need.
You don't need a separate transfer switch if your inverter already has one built in. The Go Power! ASW-1200-12-TS, ASW-1800-12-TS and ASW-3000-12-TS inverters, and every AIC inverter charger, have the transfer switch inside the unit. Shore power goes in, one output goes to your panel, done.
You do need one if:
- You have a standard inverter with outlets on the front (like the SSW-2000-12) or a hardwire inverter (like the SSW-3000-12-HW) and you want it to power the RV's existing outlets instead of just what's plugged into the inverter itself.
- You use a portable power station (a Go Power! portable, an EcoFlow, a Jackery) as backup power and want to feed the whole RV from it when you unplug.
- Your RV came with an inverter wired only to a few outlets and you want it to cover the rest.
If you only ever plug one or two things directly into the inverter, you don't need any of this. A transfer switch is for feeding the panel.
The three common scenarios
1. Adding an inverter to an RV that didn't come with one
This is the most common reason people buy a transfer switch. You install a hardwire or outlet-style inverter near the batteries, run its AC output to the transfer switch, and run the transfer switch output to the breaker panel. Shore power moves from the panel to the transfer switch's other input. Now every outlet in the RV works off the inverter when you're unplugged.
One important detail: your RV's converter (the unit that charges the batteries from shore power) is also on that panel. If the inverter powers the converter, the converter tries to charge the batteries from the inverter, which is running off those same batteries. That loop will drain your bank fast. The fix is to keep the converter on a circuit that only gets shore power. The GP-TS solves this for you with a built-in converter receptacle that is only live when shore power is present. With the TS-30 or TS-50M, you wire the converter's breaker upstream of the switch, or simply turn its breaker off when boondocking.
2. Portable power station as backup power
You keep a power station in the pass-through and want it to run the RV during an outage or a night off-grid without re-plugging anything inside. Wire the transfer switch exactly as above, with the power station's AC output on the inverter input. When you unplug from shore and switch the power station on, the whole RV runs from it. Several of the videos below show this exact setup.
3. Shore power and a generator on one RV
If your RV has a shore cord and a built-in generator, it almost certainly already has a transfer switch between those two sources from the factory. Adding an inverter means adding a second transfer switch downstream: factory switch picks shore vs. generator, then your new switch picks that result vs. inverter. The TS-50M is built with this in mind. It has a selectable time delay so a generator can come up to speed before the load transfers, and mechanical and electrical interlocks so the two sources can never bridge.
How to pick the size: match your shore cord, not your inverter
This is the part people overthink. The transfer switch has to carry the largest source that will pass through it, and that is almost always shore power, not the inverter.
| Your RV's shore power | What it looks like | Transfer switch you need |
|---|---|---|
| 30 amp service | Three-prong round plug (TT-30). One 120 VAC leg. Typical on travel trailers, truck campers, vans, smaller fifth wheels and Class Cs. | TS-30 or GP-TS |
| 50 amp service | Four-prong plug (14-50). Two separate 120 VAC legs. Typical on larger fifth wheels, toy haulers and Class As, usually with two air conditioners. | TS-50M |
A quick check: look at the end of your shore cord. Three prongs means 30 amp. Four prongs means 50 amp. That's your answer.
What about the inverter side? A 12V inverter's AC output is small compared to shore power. A 2000W inverter puts out about 17 amps at 120V; a 3000W inverter about 25 amps. Both fit comfortably through a 30 amp switch. So the inverter never drives the sizing decision; the shore service does.
One wrinkle on 50 amp RVs: a single 12V inverter only produces one 120V leg. The TS-50M is a double-pole switch, so on inverter it feeds both legs of your panel from that one inverter output. That is normal and expected. It just means both sides of the panel are sharing the inverter's capacity, so you won't run two air conditioners off a 3000W inverter. Nobody expects to.
Which 30 amp switch: TS-30 or GP-TS?
They are the same switch inside. The difference is how much wiring you want to do.
- TS-30 is the hardwire version. Three sets of terminals (shore in, inverter in, panel out). You bring your own wire and handle the converter separately. Lowest price, cleanest install if you're comfortable in the panel.
- GP-TS is prewired. It ships with an inverter plug-in cable and a dedicated converter receptacle that is live only on shore power, so the converter-loop problem described above is handled for you. Faster install, fewer decisions. The GP-TS is discontinued and sold at outlet pricing while stock lasts.
Sizing cheat sheet
| Your setup | Get this |
|---|---|
| 30 amp RV, inverter with built-in transfer switch (ASW-TS, AIC) | Nothing extra |
| 30 amp RV, standard or hardwire inverter, comfortable wiring the converter | TS-30 |
| 30 amp RV, want the quickest install with converter handled | GP-TS |
| 30 amp RV, portable power station as backup | TS-30 or GP-TS |
| 50 amp RV, any inverter or power station | TS-50M |
| 50 amp RV with onboard generator, adding an inverter | TS-50M downstream of the factory switch |
Installation videos
These are from RV owners who have installed Go Power! transfer switches themselves. They are a good way to see the wiring before you open your panel.
TS-30 install in a fifth wheel (Love Your RV, 83K views). Wires a TS-30 into a Keystone Cougar so a portable power station can run the whole trailer.
TS-50 wiring walkthrough (RV With The Tanners, 67K views). Short and clear look at the 50 amp terminal layout.
More worth watching: Kemp Outside's TS-30 review and camper install (2025), Jimmy2Tech's TS-50 install with an EcoFlow Delta Pro (2024), and a TS-30 install on a T@B 320S Boondock.
A few install notes
- Mount the switch close to the breaker panel. Short runs, less wire, easier to trace later.
- Use wire sized for the shore service: 10 AWG for 30 amp, 6 AWG for 50 amp.
- Disconnect shore power and switch the inverter off before you open anything.
- If your inverter is a hardwire model, its output goes to the switch's inverter input. If it has outlets on the front, you run a cord from one outlet to the switch's inverter input. The GP-TS includes that cord.
- Keep the converter off the inverter circuit (see scenario 1). This is the single most common mistake.
- If you're not comfortable in the panel, a mobile RV tech or our dealer network can do this in about an hour.
Browse all three in the Transfer Switches collection, or contact us if you're not sure which one fits your rig.