How to Wire Two Transfer Switches to One Generator (Easy Guidelines)

When you are installing a new generator for your home, you have to install a transfer switch. Because it’s hazardous to connect your generator directly to the main power supply panel of your home. But what about two transfer switches?

Well, technically speaking, if you want to power two or more houses with a single generator, you can actually install multiple transfer switches. So, yes, it is possible to wire two transfer switches to a single generator.

So how to do that? You just attach wires from your house breaker panel to both the transfer switches, then you wire the switches. However, you do need to take some safety precautions.  For a full how-to guide and precautions, you should take, continue reading below.

When Should You Install Two Transfer Switches?

Generator prices, as it is, are already expensive. Add to that the high amp requirement of modern homes and you are looking into spending a fortune just to power all your equipment during an outage. 

So, suppose you already own a generator and you want to use it for your home and an outdoor pump at the same time. This would require you to buy a second generator. But you can bypass this by installing two switches so that you can get two output points from your generator. This can reduce costs significantly. 

How to Install and Wire Two Transfer Switches to a Generator

Before jumping straight into the installation and wiring process, here’s a list of equipment you need:

• Wrenches
• Pliers
• Screws
• Electrical cable

Then comes the planning part. Decide where you want to put the transfer switches, ensuring that they remain accessible at all times. Also, make sure that you comply with the local building code. Also, make sure that you select the appropriate switch that is compatible with your generator. If you already own a backup generator, you need to get an automatic switch, because manual switches won’t work with backup generators. 

1. Install the Switches 

Make sure that the transfer switches you got meet the requirement of your main panel. Connect one switch to your main panel and the other one to the secondary panel.

Then run the electrical wiring from your main and sub panel to the transfer switches, making sure to install any necessary breakers as well. Then feed the wires into the inlet box from both the transfer switches. Now comes the wiring part.

2. Wire Two Transfer Switches to One Generator 

To wire the switches, connect the generator’s black wire to the transfer switch’s black wire slot. Do the same for the generator’s white wire.  Now connect the generator’s ground wire to the transfer switch’s ground wire slot. Next, plug in the generator to an outlet to turn it on.

Now to wire the transfer switches, unplug the green wire from the generator for each switch and wrap it around a screw without tightening. After that, unplug the black wire from the generator and wrap it around a different switch screw without tightening. Now make sure that both the cables are properly positioned, if they are, tighten them both.

Then comes the checking part to make sure that everything is working properly as intended. 

3. Check Things Out

After all that hard work, it is now time to test things out and make sure that everything is in proper order. First, turn on the generator and flip both switches properly. If you’ve installed everything properly, both the switches should have power output now.

Before closing everything up, go back and check the wiring one last time, because there’s nothing more important than safety. 

4. Install an Interlock Kit (Optional)

If you don’t want both switches to operate all the time, install an interlock kit. This can ensure that both the transfer switches don’t get activated together. If it does, it can cause back-feeding into the generator. 

Frequently Asked Questions and Answers – FAQs

What is a dual transfer switch?

Dual transfer switches are designed to transfer the load between a primary source and an alternative source.

What is the maximum distance between a generator and a transfer switch?

Generators are designed to work safely up to 60 to 70 feet away from transfer switches. This helps you to cut down on the noise by placing the generator outside of your home.

What are the two rules that apply to all transfer switches?

Every switch used for emergency systems must meet the requirements of NFPA 110, which mandates that each switch should be factory-assembled and factory-tested as a fully functional unit. Also, transfer switches utilized in emergency systems and rated up to 1000 VAC should be certified for emergency system usage.

Do I need to ground my generator when using a transfer switch?

Yes, if the generator is providing power via a transfer switch, you need to connect it to a grounding electrode system like ground rods.

Final Words 

So, there you have it. Hopefully, by now you’ve got a clear idea of how to wire two transfer switches and get double the benefit from one generator. Make sure that your generator can handle the required output though. Also, if you aren’t comfortable with electronics, we recommend you hire a licensed technician.

Thanks for tuning in.