National Electrical Installation Standards

Standards as High as Your Own

 
?
Monday, September 28, 1998

Question:

Which of the following meet the requirements for service conductors to be considered to be outside of a building? A Install the conduit in the crawl space. B Install the feeder under the garage floor. C Install the service conduit under a hand lain, brick floor. D Install the feeder under not less than 2 inches of concrete beneath the building.
A

Answer:

The answer is B ... uh well ... let's see ... maybe it is C ... or maybe D ... HMMM ... let's take a look at section 230-6. Conductors will be considered to be outside of a building where installed under not less than 2 in. of concrete beneath a building (that's D and probably B), where installed inside a building in a raceway that is encased in brick not less than 2 in. thick (that's C if you would consider them encased, I would count the floor the same as a concrete if the joints were mortared.) This, like a lot of things in the National Electrical Code is not cut and dried, you have to use common sense and work with the various people involved with a project plus the AHJ to find an acceptable solution.

ABOUT CQD: The Code Question of the Day (CQD) is NECA and ELECTRICAL CONTRACTOR Magazine’s flagship National Electrical Code (NEC®) public forum for the industry, sponsored by EATON. The daily distribution of Q&A generates a lively dialogue and shares relative Code-based practical responses.

SUBMIT YOUR CODE QUESTION: Click here to submit a question to for inclusion in an upcoming edition of the Code Question of the Day, or email codequestion@necanet.org

CHARLIE TROUT: Charles M. Trout, better known as Charlie, was a nationally known NEC® expert and author. He served on several NEC® technical committees and is past chairman of CMP-12. In 2006 Charlie was awarded the prestigious Coggeshall Award for outstanding contributions to the electrical contracting industry, codes and standards development, and technical training. Even though Charlie passed away in October of 2015, his work continues in spirit. NECA continues to maintain this question forum for its many subscribers in memory and recognition of all his significant contributions to making the NEC what it is today.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. NEIS can be purchased in the NECA Store in three formats: a printed or  PDF download of a standard or, as an  annual subscription service.

NECA SAFETY PRODUCTS & PUBLICATIONS: NECA produces electrical safety publications and products for the industry including jobsite safety guides, handbooks and resource kits. View a full listing of available resources and products »

IMPORTANT NOTICE: Unless the question requests a response based on a specific edition, all answers are based on the latest edition of NFPA 70® National Electrical Code®.

This correspondence is not a formal interpretation of the NEC® and any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, the NEC Correlating Committee any Code-making panel or other electrical technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services. 

UPDATE YOUR SUBSCRIPTION PREFERENCES: Subscribe or Unsubscribe from this list.