UNDERGROUND POWER INSTALLATION GUIDELINES
Transformer • Junction Box • Pole Service
ALWAYS CALL 811 BEFORE YOU DIG!
Conduit & Sweep Requirements
- Conduit sweep must be 6–8 inches away from the pole.
- When installing conduit into an existing energized transformer or junction box:
- Keep the trench 3 feet away.
- Leave the conduit sweep for the lineman to install.
- All URD sweeps must have a minimum 36-inch radius.
- Smaller sweeps will not allow cable to be pulled properly.
Conduit Sizes
Primary
- 2″ Schedule 40 PVC
Secondary
- 200-amp service: 2″ Schedule 40 PVC
- 400-amp service: 3″ Schedule 40 PVC
Trench Depth Requirements
Primary
- 38-inch trench depth
- 36 inches minimum cover
Secondary
- 26-inch trench depth
- 24 inches minimum cover
Warning Tape
Install Red “Danger” Warning Tape halfway between the conduit and finished grade.
- Primary: 18 inches below grade
- Secondary: 12 inches below grade
Transformer & Junction Box Installation
- Conduit sweeps entering transformers or junction boxes must be:
- Tight together
- Securely taped together
- New transformer and junction box locations must be backfilled with:
- ¾-inch Minus Road Mix
- Required for ICLP Fiberglass Basements
Pull String Required
Every conduit must contain a heavy-duty bailing twine pull string to verify the conduit is clear and unobstructed.
⚠️ No pull string = Linemen will leave the job.
Protect Your Conduit
Cap all conduit sweeps and open conduit ends to prevent entry of:
- Water
- Dirt
- Debris
- Rodents or other obstructions
Before Power Can Be Pulled
- All trenches must be completely backfilled.
- Bedding material is only required in rocky conditions.
- Use ¾-inch Minus Road Mix.