National Electrical Installation Standards

Standards as High as Your Own

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Wednesday, June 16, 2021

Question:

Greetings, installing 4/0,4/0,2/0 direct buried. Do I have to put anything around the cable when I bury it? I have to have it inspected and want to make sure i have it right the first time. Dean Roth
A

Answer:

Hi Dean and thanks for the question. The response is based on the information you provided. The NEC rules of concern are burial depths and that the right direct burial cable is installed. Direct burial applications under 1000 volts must comply with the depth requirements in Section 300.5 and Table 300.5. The type of direct burial cable must be suitable for that application. Section 300.5(D) addresses protection from damage if that is a concern. If these conductors are service conductors and buried more than 18 inches deep, then Section 300.3(D)(3) requires their location be identified with a warning ribbon installed in the trench at least 12 inches above the top of the direct buried cable. Table 300.5 indicates that the minimum burial depth for such cables (unless any other conditions of Table 300.5 are met) is 24 inches deep.
 
Hope this information is helpful.

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