Can You Bury an Outdoor Extension Cord? Yes, you can bury an extension cord, but don't do it, especially if you're burying the cord directly. Even if you do, have in mind that you might get yourself into trouble. The outdoor extension cord doesn't have the quality to survive the unfavorable condition when buried.
Extension cords are not rated for direct burial, and are not meant for long term exposure to the elements. They are meant for temporary use. If you are going to extend a circuit, do it right. Use conduit, run the appropriate sized wires and exterior weather-proof/ water-proof box and GFCI receptacle.
Electrical Cable Depth Options
-deep trench, use galvanized rigid metal electrical conduit with individual conductors inside. For a 12-in. -deep trench, you can direct-bury GFCI-protected underground feeder cable with a short length of PVC conduit at the house.
Professional electricians understand the important role that extension cords play, and they approve of their use, but only if they are temporary. Can you use an extension cord permanently? No, you cannot. The extension cord will wear out eventually.
Short-Term Power Supply (AKA: Extension Cords)
Do NOT leave even your outdoor extension cord outside more than a day or two. Left outside over extended periods, cord materials can breakdown, potentially resulting in sparking, fire, and shock. Always follow outdoor electrical precautions.
An extension cord doesn't use electricity. It is merely a conductor that transfers power to the appliances attached to its outlets. As such, it won't consume vampire power if you leave it plugged in, not unless it has indicator lights and displays.
Direct burial wire is a type of outdoor electrical wire that is buried underground, usually without conduit. Naturally, these cables have to possess distinct characteristics to withstand the environment of the ground.
In general, bury metal conduits at least 6 inches below the soil surface. You may also run them at a depth of 4 inches under a 4-inch concrete slab. Under your driveway, the conduits must be below a depth of 18 inches, and under a public road or alleyway, they must be buried below 24 inches.