What You Need to Know About Burying Underground Electrical Cable

When running underground electrical cable to a detached garage, tool shed, or garden pond, it’s important to follow proper code requirements and choose the right materials. Here’s a summary of what you need to know:

1. Burial Depth Options for Underground Wiring

• 6 Inches:
  • Use galvanized rigid metal conduit with insulated wires.
  • Wires must be rated for wet locations (e.g., THWN-2).
  • Best for rocky, clay soil or areas with tree roots.
• 12 Inches:
  • Use direct-buried Type UF cable with GFCI protection.
  • Common for small projects, like backyard lighting or low-voltage circuits.
  • Requires GFCI protection for safety.
• 18 Inches:
  • Use PVC conduit with insulated THWN-2 wires.
  • Good for a variety of circuits and future upgrades.
  • More cost-effective than metal conduit, but still offers good protection.
• 24 Inches:
  • Use direct-buried Type UF cable.
  • Ideal for granular soil that is easy to dig or if you’re using a trenching machine.
  • Offers protection from physical damage with PVC conduit.

2. Other Considerations

• Safety First:
  • Always get an electrical permit and call 811 before digging to mark utilities.
  • Make sure to inspect the wiring before covering the trench.
• Conduit and Cable Choices:
  • If soil is difficult to dig, using metal or plastic conduit can help protect the wires.
  • GFCI protection is essential when running power near water sources or outdoors.

By following these guidelines, you can safely bury electrical cable for your outdoor projects.