Existing Sprinkler Valve & Nearby Junction Box
Main Power Panel

Installing Electrical Outlet:
Before going too far with this project, I needed to ensure I had a viable power source nearby. Fortunately, there was an electrical junction box close to where I want to install the main controller and valves, however, the junction box had just ‘capped’ wires and not an actual outlet.

I’ve had success with TOPGREENER High Speed Dual USB Charger Outlets so I planned to use one to power this project. It’s a standard 15amp 125vac dual outlet with two USB ports rated at 4amps 5vdc. I plan to use one of the USB ports to power the Raspberry Pi Zero W and the AC outlets to power the 24vac transformer.

To protect the outlet from the elements, I’m installing the Taymac MM420C Weatherpoof cover over the outlet.

Steps Taken:

Turn Off Source Power to the Junction Box:
Because the wires were just capped and not connected, I really didn’t have a full-safe way to verify which breaker powered the junction box. As a result, I went the safe route and turned off power to my entire house from the main power panel. Notice the power is on in the image below. Photo was taken after outlet was installed.

Main Power Panel

Prepare Wires:
I removed the caps, straightened and stripped the wires. Prepare Wires

Connecting Wires
After connecting the wires, the outlet was wrapped in electrical tape to prevent any wires from coming loose or touching anything.
Connecting Wires to Outlet

Testing The Outlet
I highly recommend testing the outlet. These testers are cheap and work great.
Testing Outlet

Finding The Circuit Breaker
I highly recommend finding the circuit breaker of the newly installed outlet. For any future maintenance, it’s better to know the specific circuit breaker rather than turning off all of the power to your house.
Finding Circuit Breaker

Attach Outlet Cover
Another necessity. Covering the outlet to protect it from the elements.
Attach Outlet Cover

Seal The Seam
The junction box I installed the outlet in is a bit old and crusty. Not taking any chances on the seal, I decided to apply a liberal coat of Silicone on the seam where the two pieces meet.
Seal The Seam

Final View
Here’s the final view of the newly installed outlet with the cover attached.
Final View