Portable Generator Transfer Switch: A 2021 Guide

Your purchase of a portable generator is the first step toward being power-secure and protected against electrical outages.  Many residents native to areas prone to storm damage or natural threats include a portable generator in their preparations. However, one thing you can add to your setup to make the process easier and safer is installing a generator transfer switch.

What is a generator transfer switch?

This will more than likely be a process that you will hire a certified electrician to complete.  Any work done inside your home’s main electrical box can be dangerous and is best left to the professionals.  Once the permit for the addition is obtained, the electrician will install a smaller box. This box connects to your main electrical service panel.

Depending on which type of generator transfer switch you want or need, the features will vary. But, the common points on the switch will be a place for your portable generator to connect and a way to turn the power circuits on and off.

Importance of Function and Location

generator transfer switchA properly functioning generator transfer switch achieves the dual task of:

  • Disconnecting the regular city electrical grid, and
  • Making the connection to your generator’s feed

With the single flip of a switch, your home’s wiring is switched from the city connection to your generator connection.

This process is called shunting and is important that both take place.  Simply plugging your generator into your electrical system without removing the “dark” feed could have dangerous and catastrophic consequences when regular power is restored.  This is why a professional installation is highly recommended; to ensure function and safety.

Location is also important for the placement of your generator transfer switch. It is important that the connections can be made and maintained with minimal to effort, and to observe critical safety precautions.  Most electricians will recommend the transfer switch be no further than 75’ from the generator itself.  This mandates a shorter distance between the generator and the cutoff should anything go wrong.

It may be convenient to install the generator transfer switch directly next to your home’s main electrical panel. However, keep in mind the portable generator itself must remain outside and away from open windows or doors. This is to avoid the possibility that carbon monoxide may enter the home and present a danger.

Why do you need a generator transfer switch?

The two most common reasons you need to have a generator transfer switch installed are convenience and safety.  Both are important factors but the truth of the matter is that without a generator transfer switch, running your home on a portable generator can be more trouble that it is worth.

Running an appliance or two is one thing, but running all or even a partial home without the transfer switch is so difficult that you may try it once, and then once the crisis is over, you’ll immediately go out and have a switch installed.  So why not start out the right way without having to learn the hard way?

With the generator transfer switch, it’s as simple as one plug and a few switches (depending on your needs, capacity, and brand).  Connect your generator’s feed to the transfer switch’s input, start up the generator and once the engine is up to speed, throw the switch and watch the power restore light to the house.  Convenience when you need it the most.

Without the transfer switch, you’re going to be dragging heavy extension cords through the house to unplug appliances from the wall and manually making the connections at the end of the cord.  Not to mention, there are some appliances such as your water heater that are hard wired to your electrical system and you won’t be able to run to an extension cord.

Safety Tips and Tricks with Transfer Switches

These extension cords could present a safety concern in multiple ways.  Aside from the obvious tripping hazard, you need to be sure they are heavy enough gauge wire to handle the amperage flowing through them.  Under fed appliances will continue to draw as many amps as they need. But, if the extension cord you used can’t provide it, the cord will get hot and possibly fail.  If you’re having to store these cords, you have to be certain they are kept safe from frays and cuts as well.

A portable generator should never be connected to your home through a process called back feed.  This is where there is no transfer switch and the connection is made by plugging the generator’s output directly into an outlet.  This is a situation where knowing “a little bit” can be dangerous.

Yes, if you know how electricity flows you will see that it can work, but it eliminates the breaker protection. Additionally, it presents an over-voltage danger to your appliances and wiring once regular power has been restored.  Also of crucial note, you may be putting power workers at risk by feeding power back into the “dark” line that they are working on.  Don’t do it.

Connecting through a generator transfer switch just makes sense.  It uses the same wires in your walls as the regular power grid. Also, you aren’t having to do any extra labor by running around making connections that could become dangerous.

Which type of generator switch fits my needs?

There are two classes of generator transfer switches; the manual and the automatic. They perform just as their names suggest.

Manual versus Automatic

The manual generator transfer switch is a static box that has the same connection points as the automatic.  There is a large plug for the generator’s output. This will feed the panel and then you will throw a switch. In turn, that will move the contact points from city power to backup generator power.  That is all there is to it.  Plug it in, throw a switch.  The automatic eliminates the throwing of the switch.  It senses the incoming generator power and moves the contacts itself.

Most recommendations are for the manual transfer switch because they are far less expensive and do nearly the same thing.  The manual switch makes sense for most portable generator connections to homes.  But the automatic can make a decent case for itself under some situations such as:

You have a number of sensitive electronics connected to your home.  If you make the generator connection too early, before the engine is up to speed and producing regulated power, you could temporarily send “dirty” power into your home’s lines.  This is not ordinarily a problem for appliances like sump pumps, air conditioners, refrigerators… but could present a problem for computers and micro processors in sensitive electronics.  A good automatic generator transfer switch won’t switch power over until it sees the proper voltage and amperage from your generator.

Another reason an automatic makes sense is if your portable generator connection is somewhat less than “portable”.  If you have your generator connected and set to start on a power outage, the automatic switch will make the connection without you having to do any of the work.  For those who have special 24/7 power needs, an automatic switch would make sense to pair with your automatic generator.

Final Thoughts on Transfer Switches

Whichever generator transfer switch you get, be sure to get the appropriate size for the capacity of your generator and the draw your home will be pulling from it.  You will also consider the number of connections you need.  Some transfer switches are single switch, where the power is moved over to the wired circuits all at once, and other switches have individual breakers on them allowing you to choose which devices go on generator power and which ones do not.

Leave a Comment