How To Connect Generator To House Without Transfer Switch (7-Steps)

Do you deal with power outages often and want to get a generator hooked up without using a transfer switch? Great news, you have come to the right place! 

In this guide, you will learn:

  • How to hook up your house to a generator without using a transfer switch
  • How to calculate the size of generator you need 
  • And more!
How To Connect Generator To House Without Transfer Switch

When the power goes out, you don't want to have to leave a window or door open to run a cord through, especially if you have to deal with rain or snow!  We are going to walk you through how you can install an outlet dedicated to providing power from your generator.  

This allows you the ease of plugging your generator in outside and then plugging in whatever you need to inside. You won't have to worry about accessing anything in your main electrical panel.  

Keep reading to learn the 7 steps on how to hook up generators to houses!

What You Need To Know About How To Hook Up Generators To Houses Without Transfer Switches

Your home generator size will dictate what appliances or devices you will be able to use during a power outage.  Take a look at what you will be powering and the capacity of your generator.

If you have two 20-amp circuits available on your generator and want to utilize both circuits, be sure to install a double gang box and wire in two 20-amp receptacles.

If you want it obvious the outlets are generator-powered, you can purchase red outlets which are used to indicate that they are wired to emergency power.

This wiring job is definitely beyond the average DIY homeowner, and hiring a licensed electrician is recommended to make sure it is installed in a safe code compliant manner.

Read Also >> What Are The Best Generators For Indoors?

Supplies You'll Need To Wire A Generator To A House

  • Screwdriver - Used to make terminations and install covers
  • Wire Strippers - Used to strip the insulation off individual wires
  • Utility Knife - Used to remove the outer cable jacket 
  • Electrical Tape - Used to wrap generator connection to house for added layer of safety
  • Drill- Used to make hole through wall 
  • Female Straight Blade Plug - Used to plug in cord from generator 
  • Sealant - Used to seal hole
  • Oscillating tool - Used to cut drywall 
  • Duplex outlet(s) - Used in the house to plug into generator power
  • Weatherproof Outlet Cover - Used to cover plug connections outdoors
  • Stud Finder - Used to find studs behind drywall 
  • Old Work Plastic Box - Used to mount outlets
  • 12-2 Wire - Used to wire the outlet to the plug
  • Voltage Meter - Used to verify power on the outlet

7-Steps To Make A Generator Plug For House

  1. Size Your Portable Generator
  2. Decide Location and Prep Wall
  3. Fish Wire Through Wall
  4. Wire the Outlet
  5. Wire the Plug
  6. Seal Hole and Install Cover
  7. Start Generator and Test Receptacle

Step 1 - Size Your Portable Generator

The best way to size your generator is to calculate how many watts of power is required for the appliances you will be running. 

Wattage is typically listed on the information sticker on the appliance; just add up the wattages and that is the size you need. Typical generators range in power anywhere from 5-kW and up to 50-kW.

If you don't plan on running everything at once, you can downsize the generator to your largest energy user.  

If you already have a generator, check the size to verify what you will be able to run off of it.  The last thing you want to do is overload it and have it shut down.

Read Also >> Why 3-Way Switch Only Works When One Is On?

Step 2 - Decide Location and Prep Wall 

Pick a location that is easily accessible.  Somewhere that isn't hiding behind something that is hard to move, and verify you are between studs in the wall using a stud finder. 

When you know where you are going to put the box inside, go verify you will not interfere with anything on the outside of the house.  

Next, trace the outlet of the box on the wall. Using your oscillating tool, carefully cut along the line. 

Test to make sure the box will fit.  If not, trim the edges of the drywall until it slides in smoothly.  

Use the drill, and a drill bit big enough for the wire to pass through, to drill a hole through the wall to the outside.  

If you are using two outlets, drill two smaller holes instead of one big one.  It is easier to seal to make weathertight again.  

How To Connect Generator To House Without Transfer Switch (2)

Step 3 - Fish Wire Through Wall

Fish the wire through the wall from the outside; when you have the wire inside, feed them through the knockout from the back of the box.  Pull at least 6 inches of wire into the box. 

When you have enough wire in the box, push the box into the wall and use your screwdriver to tighten the tabs up until the box is secure in the wall.

Read Also >> How To Troubleshoot And Reset GFCI Outlets?

Step 4 - Wire the Outlet

Using your utility knife, strip the outer cable jacket to expose 6 inches of the individual wires. Use your wire strippers to strip about 3/4 inch of insulation off each wire. Use the tip of your strippers, pinch the end of the wire, and bend it around making a hook.  Repeat this for each wire. 

The black wire will terminate on the brass screw, the white wire on the silver screw, and the bare copper on the green screw.  Repeat this for the second outlet if you are using two. 

After the terminations are complete, wrap electrical tape around the body of the receptacle covering all the bare wire.  

Fold the wires back in to the box and push the outlet in; using the mounting screws to mount it in the box.  Install the cover plate. 

Step 5 - Wire the Plug 

To wire the plug, you will need to leave just enough wire on the outside of the house to easily plug the cord in from the home generator. Too much and you will struggle to get the lid of the weatherproof box closed. 

Strip off roughly 1-1/2 inches of outer insulation.  Slide the body of the plug over the wire. Strip 1/2 inch of insulation off the end of each individual wire. 

The black wire will go to the brass screw, the white wire to the silver screw, and the bare copper wire to the green screw. 

Slide the body of the plug up to the plug head, connecting the two together using the screws provided.  Make sure they seat together, leaving no gap between the body and the plug.

If you're using two receptacles, be sure to use two plugs so you can plug each one into separate outlets on your generator. 

Read Also >> What Is The Cost To Replace Knob And Tube Wiring Systems?

Step 6 - Seal Hole and Install Cover 

Seal any holes and install the cover.

Using the sealant, fill all the way around the wire to seal the hole. 

Once the plugs are wired and the hole is sealed, you can install the weatherproof outlet cover over top of the plugs.

Step 7 - Start Generator and Test Receptacle

If you have verified all your generator connections are good and everything is closed up, you can start your generator and test the receptacle.  

Once you have your generator started, run your cord over to your plug and plug it in. Go inside and use your voltage meter to verify power. 

Insert one prong into the long slot and insert the other prong into the short slot. You should have a reading of 120V.

You are all set for when the power goes out. 

Frequently Asked Questions 

Can I Use A Portable Generator Without a Transfer Switch? 

Yes, you can. You just cannot hook into your breaker box without a transfer switch.

Can I Just Plug A Generator Into An Outlet?

Unless the outlet is set up specifically for the generator, no, you should not. It can cause major damage to the integrity of the homes electrical system. Connecting to a regular outlet can also energize dead power lines and injure neighbors and utility workers.

How Do I Temporarily Connect My Generator To My House?

You can put in an outlet that is ONLY powered by the generator.  Or you can also install a manual or automatic transfer switch. 

Can You Hook Up Generator Into Breaker Box?

Yes, you are able to hook a generator into a breaker box.  You can do it via automatic transfer switch or manually. 

Read Also >> How To Add An Electrical Outlet To Existing Circuit?

Final Thoughts On How To Hook Up A Generator To Your House

Having to leave a window or door cracked open to run the cords for a generator is never fun.  A simple solution is to install outlets that are powered only off generator power.  These outlets can be the same color as the rest of your house outlets, or you can install red ones.  Red is the standard color for emergency power.

Be sure that you have the correct size generator for the amount of wattage that you want to be able to power.  At minimum, make sure it is big enough to power your biggest energy user on its own!

I hope you enjoyed this Home Inspector Secrets guide!

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