How to Connect a Backup Generator to Your Home: Installing a Power Inlet Box with an Interlock Kit
Power outages can be a massive inconvenience. If you’ve ever been through one, you know how essential keeping your home powered is—especially for things like refrigeration, lighting, and air conditioning. In this post, I’m taking you through how we installed a backup generator to supply power to my home using a 50-amp power inlet box and an interlock kit. This method ensures you can safely power your entire home during an outage and easily switch back to utility power once the grid is restored.
Why Install a Power Inlet Box and Interlock Kit?
A backup generator setup isn’t just about convenience—it’s about safety and compliance, too. The power inlet box lets your generator feed into your house safely without dangerous backfeeding, while the interlock kit prevents both utility and generator power from flowing into the house simultaneously. This prevents potentially fatal accidents, making it a necessary part of any installation. And while you can DIY the install, always reach out to an electrician if you aren’t comfortable working with wiring.
Tools and Materials
Before beginning the installation, you’ll want to gather the following tools and materials:
- 50-Amp Power Inlet Box: I chose a 50-amp model from Amazon that had solid reviews and budget-friendly pricing.
- Interlock Kit: This device ensures that your generator and utility power can’t run at the same time.
- 6-Gauge Wire (Black, Red, White, Green): For handling the power load.
- Liquid-Tight Conduit: For protecting the wires running between the inlet box and your main breaker panel.
Most installation steps can be applied whether you’re using a 30-amp or 50-amp setup. Just make sure you’re using the correct gauge wire. Thicker wire is required as amps increase.
Once you have everything together, let’s walk through the installation.
Step 1: Prepping the 50-Amp Power Inlet Box
The power inlet box I purchased didn’t have pre-punched knockouts. Instead, I had to drill them out myself. While this feature isn’t ideal, it’s something you may run into, especially with budget-friendly models. The 50-amp box I chose has the added benefit of being wider than most, making it easier to wire. If you’re like me and prefer extra space to reduce wire strain, look into larger boxes.
A small feature that some may appreciate is the green indicator light on the box. It shows you when power is flowing from the generator, but I consider it more of a gimmick. Still, it might come in handy.
Step 2: Shutting Off Power and Installing the Box
Before proceeding with any electrical work, I shut off the main breaker. Safety is the priority when dealing with electricity. After the power was off, I used a multimeter to confirm no electricity was running through the circuit.
I mounted the power inlet box to the wall, taking care to anchor it into a stud for extra support. Then, I attached conduit fittings and measured out the length of my liquid-tight conduit to ensure a snug fit.
To make threading the 6-gauge wire easier, I bundled them together with electrical tape. Feeding them through a 90-degree elbow can get tricky, but taping everything together simplified the process.
One note for beginners—if you’re unsure about working inside your electrical panel or handling larger gauge wire, this is where an electrician could be invaluable.
Step 3: Wiring the Power Inlet Box
With the wire fed through the conduit and into the power inlet box, it was time to make the connections. Starting with the ground wire, I connected it directly to the ground bar inside the box. This connection ensures your entire setup will be properly grounded, which is crucial for safety.
From there, the neutral (white wire) goes into a designated slot on the plug. It’s color-coded, so you can’t really go wrong. Next, I connected the black and red wires into their matching slots on the box. Once everything was secured, I reattached the conduit to keep everything tidy and protected.
Step 4: Wiring the Main Panel
With the power inlet box wired up, I turned my attention to the main breaker panel. A key element of this setup is the 50-amp double-pole breaker, which serves as the entry point for the generator’s power into the home.
I started by connecting the green ground wire to the ground bus bar within the panel. Then, I connected the neutral wire (white) to the designated neutral section, ensuring everything was firmly in place.
Next came the more critical connections—the red and black “hot” wires. These needed to be connected to the 50-amp breaker. Once properly attached, the breaker was installed into the panel and snapped into its slot.
Step 5: Installing the Interlock Kit
The interlock kit is essential in preventing power from the generator and the grid from running at the same time. It essentially blocks one breaker (either utility or generator) from being turned on while the other is engaged.
Installation involves drilling small holes in the panel cover to fit the interlock switch. Once the holes are drilled, I attached and secured the interlock kit, ensuring it allowed for smooth operation between the main breaker and the generator breaker.
Testing the System
After everything was hooked up, I tested the system. Here’s how the process works:
- I start my generator and let it warm up for a couple of minutes.
- I plug the female end of my generator cord into the power inlet box, ensuring a tight, locked connection.
- I connect the male end to my generator itself and flip the generator breaker to “on.” This sends power from the generator into my home’s panel.
The green indicator light on the power inlet box lit up, confirming that electricity was flowing into the house.
The interlock kit prevents me from switching on both the main grid power and the generator at the same time, ensuring I avoided dangerous backfeeding. And that’s it—my house could now run on generator power until the grid power comes back.
of course you can always hire Toronto Wiring to install a backup generator.
