Code Quiz

Jan. 7, 2010
When installing underground service conductors to a building or structure, where the service conductors are installed in a trench that has 24 in. of cover, what marking is required at what distance above the underground installation?

When installing underground service conductors to a building or structure, where the service conductors are installed in a trench that has 24 in. of cover, what marking is required at what distance above the underground installation? The underground service conductors are not encased in concrete.

  1. Marking is not required. Therefore, no distance is specified.
  2. A pressure-treated piece of lumber (2x4, painted red) is required to be installed directly over the underground installation.
  3. A red warning ribbon placed 24 in. above the underground installation is required.
  4. A yellow warning ribbon placed 12 in. above the underground installation is required.

Answer: D

When installing underground service conductors that are not encased in concrete and buried 18 in. or more below grade, you must place a yellow warning ribbon 12 in. above the underground installation. Note that this requirement applies only to service conductors.

The installation of warning ribbons above all underground conductors was once again proposed and commented on in the 2011 NEC cycle. However, no new requirements were approved by the Code-making panel members.

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at [email protected].

About the Author

Steven Owen

Voice your opinion!

To join the conversation, and become an exclusive member of EC&M, create an account today!

Sponsored Recommendations

Electrical Conduit Comparison Chart

CHAMPION FIBERGLASS electrical conduit is a lightweight, durable option that provides lasting savings when compared to other materials. Compare electrical conduit types including...

Fiberglass Electrical Conduit Chemical Resistance Chart

This information is provided solely as a guide since it is impossible to anticipate all individual site conditions. For specific applications which are not covered in this guide...

Considerations for Direct Burial Conduit

Installation type plays a key role in the type of conduit selected for electrical systems in industrial construction projects. Above ground, below ground, direct buried, encased...

How to Calculate Labor Costs

Most important to accurately estimating labor costs is knowing the approximate hours required for project completion. Learn how to calculate electrical labor cost.