Underground Utility Installation
So today’s all about underground utilities. We’ve been installing many of them on our home remodeling project in Middleton, Idaho. Right behind me, you can see a new 400-amp underground service. I’ll walk you around the project and show you our progress. We’ve been here about a week and a half, so a lot has been done.
Ancient 60-amp Overhead Service
The property originally had a 60-amp overhead service that had been in place for decades. The pole supporting it was held by a rope—an unsafe and outdated setup. As part of the upgrade, this pole and another in a nearby pasture are being removed. The pole at the street, which houses the transformer, will be moved approximately ten feet to the south side to accommodate the new system.
New Underground Service Installation
A larger pole with a higher-capacity transformer will now supply the new underground system. A trench was dug extending from the road to the new junction (J) box—about 160 feet long. The J box measures 17 by 30 inches and is set below ground to distribute power efficiently.
Conduit and Panel Installation
A three-inch conduit runs back through the trench to connect to the panel mounted on the shop’s exterior wall. Additional conduits carry low-voltage, water-line, and high-voltage lines toward the main gate. All panels—electrical and low voltage—are tied together, with a 200-amp disconnect on the left.
Meter Base and Disconnect Details
The centerpiece of the system is a 400-amp meter base flanked by two 200-amp disconnects. One serves the house, and the other is prepped for a future barn. Each disconnect has designated breaker areas, and a three-inch conduit with a three-inch sweep radius runs toward the street.
The power company will pull the wires from the pole to the J box, feeding into the meter base and sweeping into the ground. A minimum of 30 inches of soil cover is maintained over the pipe. Code requires Schedule 80 conduit for anything above ground due to sun exposure.
Expansion Coupler and Low Voltage Line
An expansion coupler is installed to accommodate temperature changes. As the ground expands and contracts, the coupler allows movement to prevent cracking or pipe separation. One remaining low-voltage line will connect later, ensuring the coupler can slide freely as needed.
Main Sub Feed and Future Barn Setup
A two-inch conduit serves as the main sub-feed from the 200-amp disconnect to the house. It uses a 24-inch radius Schedule 40 sweep below grade, turning down the ditch and leading to the home. Another two-inch conduit runs from the second disconnect to serve a future barn; it’s currently stubbed out and sealed for later use.
Low Voltage and Water Lines
Two one-inch Schedule 40 conduits are in place for low-voltage wiring—cable and phone—to the barn. A water line is also installed and will be tied in when the barn is built. A frost-free hydrant provides year-round access to water without freezing, with pea gravel at the base to allow proper drainage when the handle is shut off.
Drain and Gate Power Setup
The system includes a drain for a future irrigation valve. For the driveway gate, a one-inch conduit supplies power to the gate operator. Additional circuits were installed to power horse water heaters, with breakers located in the main panel. For low-voltage wiring, sealed cans without holes were used to prevent moisture intrusion.
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Hub for Phone and Cable Distribution
We have a hub for phone, cable, and everything from the street, and we distribute from there. Six conduits tie in here, with an additional one for a camera at the gate. Let’s walk down the ditch and see how it’s all laid out to meet code. Separation between low-voltage, high-voltage, and water lines is maintained.
Conduit Layout in the Ditch
Now, we’re walking down the ditch, seeing where all the conduits tie in at the shop. This is a combination of high-voltage, low-voltage, and water lines. The three-inch main service pipe is on the right. We need a 12-inch separation between low-voltage lines and the main service. This trench is three feet wide, with a specific layout for each type of line.
High-voltage and low-voltage lines can cross perpendicularly. This high-voltage two-inch line is crossed by the low-voltage above. We pack dirt under pipes to prevent settling during backfill. The irrigation line has a compression coupler for repairs. This three-inch main service is on the left, low-voltage in the center, high-voltage, and water line on the right.
J Box and Power Company Setup
A 17 by 30 J box will be installed here, with a 28-inch spread between conduits for wire folding. The power company stakes and holds these conduits in place. The sweep heads back to the road. Along with the main line, we have three low-voltage lines: one for the gate operator, one for the phone, and one for the cable.
Future-Proofing Low Voltage Lines
There’s only a phone line, but we’re running extras for future use. This high voltage line will power horse water heaters and the gate operator. Sweeps come up for service, and water lines are in place. We installed frost-free hydrants with pea gravel for drainage, preventing rusting below grade. Workers are installing another hydrant and high-voltage line for a horse trough.
Gate Operator and Loop Sensor
This low-voltage line runs to the gate for a loop sensor, triggering the gate to open. Separation is maintained between the main service, low-voltage, high-voltage, and water lines. This run is about 160 feet. We did all the digging with a mini excavator. We capped the line for future tie-ins.
We have a low voltage for the gate and a high voltage for the gate operator and camera. Another frost-free hydrant is installed. We swept up for phone access at the pedestal and left an extra line for the new pole. The vacuum truck blew out a hole, leaving flexibility for the pipe. Idaho Power requires this setup.
NEED HELP?
If you need help building a custom home, ADU, or whole-house remodeling, request a project consultation with us. We have offices in Ramona, California, serving the San Diego County area, and Middleton, Idaho, serving the Boise Metro area. You can also explore our comprehensive collection of similar videos on our YouTube channel, The Real Property Show.
