Installing A Portable Generator Outlet On Your Home

GeneratorOutlet.jpgHaving a portable generator but only using extension cords to power your home is like having a car with only one seat. It works and gets the job done, but adding more seats or in the case of the generator, adding a receptacle to your home allows you to leverage the full capabilities of your generator and live much more comfortably.

Portable Generators of about 3,000 watts or higher generally have heavy duty power connectors meant for connecting heavy loads beyond a basic extension cable. In the case of my 7,500 watt generator, it has a large four prong outlet that’s meant to connect a 30 amp cable to a receptacle.

I purchased the Reliance Controls PB30 L14-30 30 Amp Generator Inlet Box which matched the connector (L14-30) on my Champion 7,500 Watt with Electric Start  perfectly. These generator outlets are universal and generally go by the number of prongs. Smaller generators will use receptacles with less prongs, bigger generators will have more. It will often say right on the generator outlet what type of connector it uses (L14-30 in my case above).

I spent about $45 on the outlet box itself and paid an electrician $350 to install it on my home. Installation included him installing a double 30 amp circuit breaker in an unused space in my 200 amp circuit breaker box, running an electrical line from that new breaker through the wall outside to where the generator outlet would be installed, then attaching that electrical line to the outlet.

Essentially how the final setup works is that the new breaker the electrician installs acts as a “MAIN” on/off for the generator connection, just like the big “MAIN” breakers at the top of your panel turn on/off power to the panel from the electric lines.

genpowercordThe last item you’ll need is a generator power cord long enough to connect from where you’ll run your generator (far enough away from your home to keep exhaust fumes from entering and harming your family) back to the receptacle you installed on your home. I purchased the Powertronics 30 Amp L14-30 Generator Power Cord which I found to be a good quality cable.

In the event of a power outage, you’d follow the steps below:

  1. Shut OFF the Main Breakers at the top of your circuit breaker panel
  2. Start your generator to let it warm up
  3. Connect the power cable from the generator to the receptacle box
  4. turn ON the circuit breakers in your panel connected to the receptacle box.

Reverse the steps above when switching back to utility power.

That’s it. At this point you are powering your entire panel (and therefore anything in your home) with your generator. Be smart about it though. Unplug anything you don’t need, shut off all lights and appliances not in use. If your generator isn’t powerful enough to power everything you have on, it will bog down and shut off. Even if it is powerful enough, you’ll use more gas powering more items.

I made a map of all of the lights and outlets in my home in an excel spreadsheet showing which circuit breakers power them. I taped the spreadsheet next to my circuit breaker panel so I’d easily be able to tell which breakers I can leave turned off (marked red) and which I always need on (marked green).

Be mindful it is EXTREMELY important that you shut off the MAIN breakers at the top of the panel BEFORE turning on the generator breakers. Not doing so will send electricity from your generator back into the power lines on the pole. The transformers on the pole will step up the voltage to levels high enough to kill people. When the utility workers touch a line that they think is dead, they will get shocked and could die.

Some states require an interlock switch to be installed in your circuit panel that physically prevents you from having both the generator breaker and the main breakers on at the same time. Check your local regulations to ensure compliance.

Another option for portable generator connections that eliminates the need for a checklist or concerns about having to shut off the Mains is a manual transfer switch like the Reliance Controls 10 Circuit Manual Transfer Switch Kit which comes with pretty much everything you need to connect your generator to your home power safely. Personally I’d buy it then have an electrician install it for me, but there are youtube videos showing how to install this yourself. It doesn’t look too tough, but I’m not confident enough in my abilities to mess around in my circuit panel, so I leave it to the pros.

The main drawback to using a manual transfer switch is that you have to pick which ten circuits (ten assuming you have the one I linked to above) in advance and you cannot power anything in your home that isn’t on those ten circuit breakers. The benefit to it is that you don’t have to worry about remembering to shut off the main breakers in your panel.

When using a manual transfer switch, you just start your generator, connect the power cord to the house, then flip the switches on the transfer switch from “Line” to “Gen”. You don’t have to flip any other switches.









1) Generator, 2) Generator Receptacle on outside of home, 3) Manual Transfer Switch, 4) Circuit Breaker Panel

If you don’t opt to use the manual transfer switch the setup is the same, minus number 3 in the picture.

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4 Responses to “Installing A Portable Generator Outlet On Your Home”

  • Very helpful…thank you for all the useful information

  • Interested.

  • What outlet box did you purchase?

  • Good writeup. It’s incredibly easy to do yourself though. Installing an interconnect on the panel is dead simple if you order the right one for your particular electrical box. You have to move the topmost breaker down so you can slip in the 30A breaker for the generator breaker which has to be at the top (R or L side, depending on the panel and the interconnect kit). If the wires aren’t long enough to reach the moved breaker’s new position, you’re perfectly entitle under the Code to use a wire nut and extend the wire as long as you do so in the panel. Then you just connect the inlet lugs and connect the other end of the feed wire into the panel: red and black to your breaker, white to the neutral bar in the panel and green to the ground bar in your panel. It’s so so easy and painless. No need to pay an electrician for a dead simple project. There _are_ some projects where you need a pro, but this really isn’t one.

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