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How Deep Do I Bury UF Cable To My Post Light?

March 26, 2006

Q: I’m installing a new post light at the end of my driveway. The trench will be a straight shot from my house down the driveway (approximately 40′) to the post light. What is the minimum burial depth for the UF? Is it necessary to ground the metal post?

A: The answer is found in Table 300.5 and is based on a number of variables. Let’s look at them. The maximum UF cable burial depth is 24 inches and applies where the cable is run under streets, highways, roads, alleys, driveways and parking lots. For one and two family dwelling driveways and parking areas used for dwelling related purposes, the maximum burial depth is reduced to 18 inches.

Residential branch circuits rated 120 volts or less with GFCI protection and overcurrent protection not exceeding 20 amperes qualify for a burial depth of only 12 inches, which applies where installed under dwelling driveways and outdoor parking areas associated with one and two family dwellings.

Part (B) of 300.5 requires grounding and bonding of underground installations. The equipment-grounding conductor in the UF cable must be connected to the metal pole supporting the luminaire (lighting fixture). This conductor must comply with 250.118 and be sized according to Table 250.122.

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One Response to “How Deep Do I Bury UF Cable To My Post Light?”

  1. Chris PRice on August 28th, 2009 5:27 am

    I need ro run 75 ft of 110 from my outside box on my house to a 18 pole in my garden. I am conecting on a low voltage 12 volt 100 amp land scape lighting system.. how deep must I burry the 110v cable and do I need to put a sheith around it. I have seen and worked wi flexable pvc style will this work.

    I alshave two 20amp GFCIs for borth ends and the special rain covers for the plugins. Please Help;
    Chris Price
    Have hade had some ex.p in wiring my crawl space and garage , but never outdores under ground.