How to Connect Generator to House with Transfer Switch?

How to Connect Generator to House with Transfer SwitchGenerators are convenient when it comes to power outages. Having one connected to your house can be a great deal for you. It will help you protect your family during a power loss.

One of the safest ways to connect your generator to your home is by using a transfer switch. It makes it easy and secure to use the generator. But what is a transfer switch? You might ask. A transfer switch is an electrical device installed next to the home electrical panel.

It works by connecting the electrical panel you want to power during the power outage. That allows you to prioritize the items to run with the available generator power and also do away with running the extension cord.

And why do I need a power transfer switch? It’s a requirement by National Electric Code and the safest way to connect a generator to your home directly. It also prevents back-feeding, which can occur when the power comes back on. It does allow you to use the home wiring system to power your appliances, eliminating the need to run extension cables.

10 Steps to connect a generator to house with transfer switch

Now that you know what a transfer switch is, it’s high time you know how to connect a generator to your house using a transfer switch. With a transfer switch, all you need is flip a switch, and the generator should power your appliances. Here is a step-by-step guide on how to connect generator to house with a transfer switch.Connect Generator to House with Transfer Switch

Step 1: Turn off your main home power breakers

Your safety should come first. Since the home power side might still be electrified, you need to ensure the circuit breakers are all off. Once you’re done, you can now install the transfer switch panel near to the house service panel, few inches or so. Use a length of conduit to connect the two power panels. Remember to remove the knockout from each power panel.

Step 2: Run the cables

Once you’re done with step one, you now need to run 14/4 cable between these two panels. Next, secure the white cable to an appropriate neutral bus bar and the ground wire in the ground bus bar in your service panel and the same in the transfer switch panel.

Step 3: Install a circuit breaker

The next step is installing a 30-Amp, 240-volt circuit breaker in your service panel for the generator power. Once you’ve done that, you need to connect the red and the black wires from 10/4 cable you used in the previous step to the circuit breaker. You can now safely insert a new circuit breaker into service panel bus tabs. Next, connect these two wires, red and black, to the ‘from power lines’ feeder connectors.

Step 4: Determine the circuits you want to power with the generator

Add the wattage of all the appliances you want to power with the generator. Remember to leave around 20% of the generator power as a reserve. Also, motor appliances need extra starting power. Your total wattage should add up to approximately 80% of the generator power.

Step 5: The switching itself

Now, this is the messy part. You need to remove the black wires connected to the circuit breaker in the home service panel. These are the cables to the primary circuit you need switching. You can lengthen them in either of the following ways depending on the local building codes.

  • You can use the wire nuts to extend the above black circuit wires to reach your newly-installed transfer switch panel via the conduit you installed.
  • Remove the wires of your selected circuits from the bus bars and circuit breakers in the service panel. Connect them to the longer wires inside your separate junction box(s).

The wire nut is a more straightforward method, and junction box more is the more accepted method.

Step 6: Run the Extended Wires

If you decide to go with method one, then you need to run your chosen circuits extended wires via the installed conduit. Connect their ends to the circuit breakers of your transfer switch.

Step 7: Run wires from the junction box

If you decide to go with method two, you have to connect the chosen circuit wires from your junction boxes to the circuit breakers and right bus bars inside your transfer switch panel.

Step 8: Connecting the Flanged Inlet Connector

If your transfer switch panel doesn’t have an inbuilt 30-Amp flanged inlet connector, then you’ll have to install it.

For that, you need to mount this flanged inlet box outside the house and near the place you plan to run the generator from. Drill a 3/4-hole through the wall, screw the inlet box outside the wall and run the same 10/4 cable through to the transfer switch panel.

Screw the wires to the connector, with the red and black wires going to the brass-cored screw terminals, the white one to the silver connector screw while the green wire is going to the green screw terminal.

Step 9: Connecting the terminals

Now, you need to connect the 10/4 cable to your transfer switch panel. To do that, you do need to join the white neutral and the green ground wires to their appropriate neutral and ground bus bars. Next, connect the red and black red hot wires to feeder connectors labeled ‘from the generator.’

When connecting your generator to your house, you require a 10-gauge, 4-conductor cable. The generator end needs to have a male twist lock while the other end, connecting to the flanged connector should have a female twist lock.

Step 10: Testing and inspection

If you’re a certified electrician, you can go ahead and do the testing and be careful. If you are not an electrician, then you need the work to be inspected and tested before using it.

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About the author

Sharif Miah

I am Sharif, 22, a student, currently doing the BBA program. Besides, I am an online Blogger.

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