Best automatic & manual generator power transfer switches

Have you ever wondered how important facilities like schools or hospitals ensure their power runs day and night? An outage of even a few minutes can cost precious time and sometimes even life. These products take on the Herculean task of redirecting the connected load circuits to the primary or secondary power source. This way, you never face an outage.

It means all-important electrical equipment and machines will have a constant power backup source as long as they are connected to the circuit. A generator is also sometimes used to power RVs since it’s more convenient to charge from an outside source like a generator.

But there is more to them than just providing uninterrupted electricity to your home. Suppose you choose to forego transfer switches and manually connect your electrical devices directly to the outdoor generator. You may be putting your home or workplace at risk. Why is that?

Firstly, you will need to keep certain doors and windows open to allow the extension cords to pass. Even though the windows might be the frosted type that ensures privacy, they’re probably not going to keep the burglars out. Contrary to popular belief, the generator does not automatically stop its supply to the devices once the outage is over. Instead, electricity rushes back down to the generator itself.

It could mean damaging your generator. Worse, it could cause electrocution or fires. They provide a smooth transition that keeps you sleeping soundly and safely at night. Even if you’ve got a gun safe handy for security purposes, it’s probably best to invest in one to keep the doors locked too.

But it can be tricky to choose the right switch when there are so many options available. Let’s read about the types of switches and choose the best automatic & manual generator power transfer switches.

What to look for?

Do you want an automatic or manual?

One of the first things to look for is the mode. Manual transfer switches involve a lever or handle that needs to be turned. This way, the power source can be switched from the utility or main power to the secondary source. The secondary source is usually a generator.

That means one person will be given the task of sitting next to the MTS panel to turn this handle when the power goes out. While this may sound a tad inconvenient to some, a manual switch does have its advantages.

A manual switch can be the cheaper choice for someone on a budget. Additionally, the purpose is to avoid those pesky cables running from your appliances to the backup generator outside. Your home or workplace looks neat and uncluttered at all times! But if you’re looking for gauge wires and extension cords, check out our resources on amp wire sizes and cords.

Additionally, the MTS also comes with cons that can’t be ignored. The lever will need to be turned manually at all times. It means someone will need to be around for the power to be restored in the facility. It can be a bummer if you’re looking for an automated power backup. But don’t worry, we’ve got you covered.

The ATS monitors the frequency and voltage with its intelligent microprocessor. It automatically switches from the main power to the generator when it senses the fluctuation. It means no manpower allocation at the location and utilization of time and human effort on more important things.

The intelligent machine that the ATS is will only switch and connect to the backup sources when the primary source failure is detected. It is an important feature that ensures the main and secondary power sources are kept separate for the safety of workers and families. The extra cost is completely worth it!

If it’s money you’re worried about, get a glimpse of this resource we have on oil rig workers’ salaries.

  • The Transition – Open or closed?

When you choose one, it’s important to learn how the transition from the utility to generator backup will occur. Which option is best for you? Each transition has implications for the time it will take to switch to the backup electric source. Here’s a list of your available options:

Open transition

It typically means the connection to the backup power source will first be opened. Then the power will be activated to the connected devices. It usually means a delay of a couple of seconds while the transition takes place. But if you can live with that, this option might save you a couple of bucks.

Fast closed transition

A closed connection means there is always continuous power in the facility. It is a time-saving deal because the connection doesn’t need to be opened to the backup source. Both sources run parallel to each other. The connection to the generator is activated when the utility power is disrupted. When both the sources are available, the backup generator source automatically switches to the main.

The transition is so smooth that no interruption is sensed in the electricity!

Sub-cycle transfer

If you’re a nineties kid, you might have seen this one with computers back in the day. It was connected through a UPS device. Since it consumes a quarter of the power cycle, it causes a slight interruption that is noticeable. However, the backup is quickly activated and runs smoothly after that.

Soft- closed transition

Similar to the fast-closed transition, there is no delay in the switch with soft-closed transitions. However, here the mechanics are slightly different. A ramp load impulse is used to synchronize all the sources. From this, the devices are connected and made sure to be running at all times.

  • Continuous Current Rating

Let’s get dirty with all the intricate details now! The switch you select should carry the maximum current load for at least three hours. The common ratings are typically between 30 and 400 amp—the most common range between 30 and 200 amps. The current rating is dependent upon your main circuit breaker. If the main circuit breaker carries 100 amps, your switch should also carry 100 amps. 50 amps for breaker translates to 50 amps in the switch.

Maybe you’re looking to gauge wires to connect to the breaker. Check out the correct wire and cord size to match your breaker capacity here. If you’re confused about the units and want to look at a reliable conversion chart, we’ve got you covered right here!

  • Voltage

This is an important feature to look out for since they are delicately rare devices dealing with two sources at once. Adequate insulation is necessary to deal with the sudden increase and decrease in voltage.

The voltage ratings for an ATS can range anywhere from 120 to 600 volts. The usual frequencies are 50 or 60 Hertz.

Other voltage and frequencies can also be used, but it’s best to see what fits your requirements and then take your pick.

How to install it?

You can now get started with the actual installation that will allow your home or facility to be powered 24×7. Before we begin, here’s what you are going to need:

  • A generator. It will be your main backup source, usually kept in the backyard or garage.
  • A power transfer switch, automatic or manual. It will work the magic of switching to generator power when the main power is out.
  • An inlet box. This box is mounted on the outside of your house. It is where your generator cord is plugged in to connect to the indoor transfer switch, which is on the other side of the wall.
  • Generator extension cord. You will need a sturdy and adequately lengthy cord to connect the generator to the transfer switch.
  • A drilling machine
  • It’s a good shower to step into after you’re done, especially if it’s a hot day.

When you’ve gathered all the above, it’s time to get dirty!

We recommend this job for at least basic familiarity with electric work. You can also seek professional help and get this job done in a couple of hours.

Let’s get started!

How to install a power transfer switch

  1. Decide where you want it to be located.

    This is important. You might have selected the most premium model. Still, it’s no use if it’s inconveniently located in a corner away from your panel box. Choose a place tucked away from human touch and close to the main panel box.

  2. Assign labels and numbers to ease the process.

  3. Mount your switch.

    Once your spot is selected, start mounting your switch to the wall. You can do this easily by labeling the placement of the mounting screws first. Remember, it should be mounted around 1.5ft away from the center of the main circuit breaker. Use screws to attach the screw to the wall.

  4. Turn off the main power to your house.

    Make sure the power is off by turning your appliances on and off. Spend plenty of time on this step because it could prove dangerous to do electric work while power is left on accidentally.

  5. Connect wires from the switch to the breakers.

    Step 2 would have made it easier for you to keep track of the devices and their respective breakers. Now, join the wires from the power transfer switch to the main circuit breakers.

  6. Get drilling!

    You’re going to need a drilling machine for this step. Drill a hole of 1.5 inches through the wall from the outside of your home close to the switch. This hole will fulfill the job of snaking wires from the switch to the electrical receptacle.

  7. Mount your electrical outdoor box above the hole.

    This box may have along when you made the purchase, or you can easily purchase one from your nearby hardware store.

  8. Snake the wires from the hole to the box to the transfer switch.

    You can do the opposite as well. Run the cable from the switch to the box and then through the hole. Whatever works for you!

  9. Connect the electrical cable to the electrical receptacle.

    Take the cable and connect it to the receptacle in the outdoor electrical box. You can screw it to the box now to assure sturdiness.

  10. Test your work.

    Keep the power off. Using the generator cord, connect the outdoor receptacle to the generator. Turn on your generator and turn the turn switch lever. All your connected devices and appliances should be working.

  11. Cover the main circuit breaker.

    As part of wrapping up, take the cover and put it back on the main circuit breaker to keep moisture and pesky rodents and bugs out.

  12. Turn the main power back on.

    Once the testing is done, you flip it again to return to the utility power mode. It means it goes back to using the primary power source. Now it is safe to turn your main electricity back on. Of course, all this would be automatically done in the case of the ATM.

  13. Cover the drilled hole.

    You can permanently seal the hole for wires to prevent unwanted bugs and moisture. You might want to cover the whole generator and transfer switch area with metal sheets. It’s done to ensure safety and protection from rain and crawling toddlers and pets.

Other things to keep in mind

  • Always check the laws and codes:

Always check the building codes and housing and electrical laws in the state before beginning the installation.

  • Confirm the wires used.

Each switch model will differ in its wires and cords and thus might not match the ones mentioned in our installation process. Refer to a specialist in case of confusion.

  • Follow the book!

It is good to follow the manufacturer’s instruction manual while installing.

  • Seek help!

It may be better to hire a professional if you have very little experience with electrical wiring.

  • Find the correct location for the generator.

The generator should be at least 20 feet away from the house for your family’s safety. The carbon monoxide rising from it can prove poisonous for your family or dogs.

  • Cover and clean!

To ensure the long life of your generator, it should be kept covered when not in use. It should also be regularly cleaned to avoid debris obstructing its smooth functioning. Maybe you choose to buy a cover. Remember to remove it while the generator is on to not act as insulation and cause it to overheat.

  • Empty the fuel tank.

Did you know leftover fuel in the gas tank can turn into gum deposits? These deposits will stick to the inside of the tank and cause your generator to function at lower than best capacity. That’s why it is best to empty the fuel into a gas container when it is not in use.

  • Always keep reinforcements!

Keep a full container of backup fuel in case of long outages that can last for days on end. It’s also best to keep backup oil and oil filters in case new ones are needed during the outage.

  • Remember to note the wattage of your generator before you bring in the big guns.

A 500-watt generator might be sufficient to keep home electronics and small tools functioning. But plugging in a lawn tractor might cause it to shut down and leave that pretty garden waiting for a trim. You’ll need a 2000-3000 watt source to keep the front yard looking pretty. And of course, some gardening tips about tomatoes and cucumbers will also help.

They are nifty little things that keep your home safe and powered at all times, so your normal life isn’t disrupted. Making the right choice of the switch and correct installation can make all the difference in an organized and well-functioning household.


Is there an automatic transfer switch for a portable generator?

Typically, a manual transfer switch is used with portable generators since it’s more compatible and functional. However, automatic transfer switches are considered suitable for standby generators instead.

What size transfer switch do I need for my generator?

The size of the transfer switch primarily depends on the largest outlet of your generator. So if the largest outlet operates at 40A, your transfer switch of choice should be a 40A one.

What are the two types of automatic transfer switches?

The two types of automatic transfer switch currently available on the market are circuit breakers and contactor ones.

How much does it cost to install an automatic transfer switch?

An automatic transfer switch can cost anywhere between $600 and $2000 on average. The estimate is inclusive of the labor cost.

How do I choose a generator transfer switch?

If you’re struggling to pick the right generator transfer switch, here’s a set of steps you can follow:
Step 1: Measure the amperage requirement. Ensure your transfer switch can handle the current load of your generator. It’s essential to pick the correct size switch. Amperage requirement is measured by viewing the largest outlet of your generator. Typically a switch size matching the largest outlet is considered ideal.
Step 2: Assess the ideal type of transfer switch. Once you’ve got the amperage figured out, it’s essential to choose the right transfer switch circuit. Depending on the usage, you could select a single, dual, or multi-circuit. A dual or multi-circuit is ideal for large generators and high usage levels. But for low usage or smaller generators, a single-circuit is more suitable.
Step 3: Establish the location of the transfer switch installation. Depending on the site, outdoors or indoors, additional components are added to a transfer switch. If you’re planning to have the switch installed outdoors, you’d require ones that come with a NEMA 3R designation.