How does an RV automatic transfer switch work?

This blog post will answer the question: “How does an RV automatic transfer switch work?” We will discuss the functions of an RV automatic transfer switch and describe a few key components. We will also discuss the process of installing an RV automatic transfer switch and list out some of the best switches available.

How does an RV automatic transfer switch work?

An automatic transfer switch works by switching between two inputs and connecting to a single common output. A transfer switch will connect one input to the switch’s output. Unlike manual switches, there is no need to move any lever on the box. These automatic transfer switches are controlled under certain conditions to get the job done.

Most of the transfer switches that are used in RVs are generator priority. These switches can connect to shore power even when there is no power present. Only one input can be connected at a time to these transfer switches. The advantage of transfer switches is that they are not high maintenance, but there are a few tips to keep them performing well.

The functions of an RV automatic transfer switch

The RV automatic transfer switch is like a gateway to the electrical supply of an RV. The job of the transfer switch is to control the flow of electricity from the main electrical utility to the generator. It helps in switching power from the generator and the electric panel. Here are a few functions of an RV automatic transfer switch.

Switching of electric supply

This switch will activate secondary power supplies from the generator. The generator is always in standby mode and you cannot go back and forth all the time to switch it on. Hence, automatic switching takes place with the use of a transfer switch. This switch is connected to the generator and the electrical utility. When the power is back, it shuts off from the generator and connects to the utility.

Starting up the power

Generators usually take around a second or two to get started and run. This is usually the time delay engine start that is common in generators. The automatic transfer switch will determine the correct voltage for the generator to operate and get started. This switch plays a vital role in RVs, especially when you keep switching between generators and the electric utility.

Monitoring the load

The automatic transfer switch also helps in monitoring the load and synchronizing. It monitors the voltage and acts as a sensor in case of a surge or spike in power. It has relay switching, contractor switching, digital multi-meter, and timer relay functions. Monitoring the load is essential and the right amount of supply is essential.

Overload protection

  • Overload is very common and it can cause damage to certain electric appliances if you are not careful. 
  • The automatic transfer switch also acts as a protection from overload. Keeping the utility and the generator safe is important. 
  • There can always be a fluctuation in current and voltage supply. In case of overload, the automatic generator switches trip in some situations.
  • An automatic transfer switch is a must-have for any RV since it is the only way to draw energy from the external power source and the onboard generator of the RV. 
  • It is also safe to have an automatic transfer switch since it prevents electrical back-feeding. 
  • Shore power or external power can overload the electric system of the RV and a sudden surge of electricity can burden the generator.

Having an automatic transfer switch can help in preventing such situations. It is more of a safety device that allows you to feel safe knowing that your RV electrical system is working in the right manner. This is also very important when using shore power at campgrounds. Switching between shore power and the generator will not be dangerous with an automatic transfer switch.  

Components of an automatic transfer switch

The automatic transfer switch connects power from the shore and the onboard generator when needed. There are a few components and variations of these automatic transfer switches that are good to know. Below are some of the key components of the automatic transfer switches that are built for RVs.

  • 30-amp and 50 amp RV power sizes.
  • EMS under/over voltage protection functions.
  • Built-in surge protector.
  • Set for default shore power and switch to the generator when required.
  • 30 to 40-second delay after starting the generator to stabilize the power.
  • The capacity to start the generator if the shore power fails.

Installing an RV automatic transfer switch

A transfer switch consists of a series of contactors and a circuit board. You will need to mount the automatic transfer switch and have the generator output directly powered in the RV’s power system. Whenever the RV is on shore power, it will automatically function on shore power. The automatic transfer switch will transfer to generator power when required.

If the generator is shut down, it will switch back to shore power. The advantage is that the transfer switch will provide 30 to 40 seconds for the generator to warm up before transferring the load. Here is how to install an RV automatic transfer switch. Note that is it always advised to contact an experienced professional if you are not aware of what you are doing.

  • There are four terminals inside the automatic transfer switch. Tow terminals will have a label above that states shore power line and two will have a label above that states generator power line. 
  • You will need to connect the shore power line and the generator power line to the right terminals. 
  • After connecting the two, you will need to connect the output that goes from the power distribution center to the RV.
  • The most important and key step is to find the right spot for placing the automatic transfer switch. It is usually placed in a position where the shore power line and the generator power line are easily accessible. 
  • Make sure that the shore power cord and the generator power cord are in good condition before connecting the automatic transfer switch.

Best automatic transfer switches

The market is flooded with various automatic transfer switches and there are many brands available. The most important part is to know the type of switch that will suit your RV. Be sure to check if you need a 30 amp or 50 amp RV transfer switch. Here are some of the best automatic transfer switches.

TS-30 automatic transfer switch

This go power TS-30 automatic transfer switch has a built-in knockout and is also simple to install. There is no complex wiring work to be done in the panel and it comes with the right instructions to install it yourself. This acts as an automatic transfer switch for a generator, shore power, and inverters. This is one of the best multifunctioning transfer switches available.

Xantrex automatic transfer switch

This switch is compact and also suitable for houses. It is one of those well-balanced devices and is foolproof. This can also be used for structures that are powered by solar and grid sources. It has a power plug that can be connected directly to an inverter. It is easy to switch between alternative power sources with this automatic transfer switch.

Spartan power automatic transfer switch

The Spartan power automatic transfer switch is perfect for RVs and it also comes with an LCD control panel making it easy to use. One advantage of this transfer switch is the capacity to control the battery bank. It is also an affordable product that comes with a two-year manufacturer’s warranty.

Progressive dynamics automatic transfer switch

The progressive dynamic automatic transfer switch is a heavy-duty product that is a good fit for an RV. Some of the top features are the automatic current detection, easy access to front panels, built-in schematics, and the capacity to prevent accidental overloading. This is also built to support the load at homes and a few industrial appliances.

Note that working on an automatic transfer switch can be dangerous since it is an open panel. Avoid fixing or performing tests on your own if you are not qualified. It is also better to call a professional for help. There can be a malfunction if you fix the automatic transfer switch in the wrong manner.

Conclusion

This blog post has answered the question: “How does an RV automatic transfer switch work?” We discussed the functions of an RV automatic transfer switch and described a few key components. We also discussed the process of installing an RV automatic transfer switch and listed out some of the best switches available.

Citations

https://www.rvtechmag.com/electrical/chapter4.php#:~:text=An%20automatic%20transfer%20switch%20is,feed%20to%20the%20breaker%20panel.
https://www.generatorjoe.net/html/whataboutsws.html

http://www.electricalterminology.com/automatic-transfer-switch/

https://www.electricgeneratorsdirect.com/stories/40-How-To-Pick-the-Perfect-Automatic-Transfer-Switch.html

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