How deep should the trench be for underground wires?
According to the National Electrical Code, Article 300.5 and Table 300.5. Here are the most common trenching depths: • 24 inches for all voltages above 30 volts not protected by conduit or GFCI protection. Caution ribbon installed 12 inches above wires. • 18 inches installed in non-metallic raceway conduit. Caution ribbon installed 12 inches above wires. • 18 inches under minimum 2 inches of concrete or a driveway. Caution ribbon installed 12 inches above wires. • 12 inches for maximum 120 volt, not more than a 20 amp circuit and protected by GFCI. • 6 inches for control of lighting and irrigation systems not more than 30 volts. • 24 inches if you are not sure how deep. Caution ribbon installed 12 inches above wires.
