Standards as High as Your Own
NECA Online Help Desk Please leave a message
We have a solar powered lighting pole and the conduit in its concrete pole foundation meant for running ground wire from earth rod to inside of pole is blocked. So, can we have this grounding bare tinned coated copper wire installed as exposed and connect it 50 cm above ground? The size of wire is 25mm square. Or should we run it through a pvc conduit for mechanical protection. This lighting pole is located in the middle of road for road lighting.
Hey Khider thanks for your question. Using NEC Table 8 in Chapter 9, the 25 mm2 conductor is larger than 4 AWG but slightly smaller than 3 AWG. Grounding Electrode Conductors 6 AWG and larger can be run along a surface if not exposed to physical damage as stated in 250.64(B)(1). If exposed to physical damage they must be protected as stated in 250.64(B)(2) - which includes rigid polyvinyl chloride conduit (PVC). PVC conduit that is exposed to physical damage must be identified for that use (Schedule 80) as stated in 352.10(F) and explained in the Informational Note.
The pole you describe is probably located in a median between roads because if it was in the middle of the road we have much bigger problems. Grass covered medians are often mowed using large mowing equipment which can be a physical damage concern. If spraying for weed control or other reasons is also done there might be a concern about corrosion. The entity responsible for the roadway might also have additional requirements.
So it seems given all the possible conditions that could exist using Schedule 80 PVC conduit as a minimum would be prudent. It is a judgement decision by the AHJ if a different wiring method, or other means of providing physical protection is necessary.
ABOUT CQD: NECA’s Code Question of the Day (CQD) is a leading National Electrical Code® forum for NECA and the industry. The CQD generates a lively dialogue and relative practical and Code-based responses to an ever-increasing and interactive audience.
IMPORTANT NOTICE: All answers are based on the latest edition of the National Electrical Code®, unless the question requests a response based on a specific edition. This correspondence is not a formal interpretation of the NEC®. Any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, or any technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services.
ABOUT CHARLIE: 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. Charlie was also a member of NECA’s Academy of Electrical Contracting. Charlie’s experienced team of industry experts keep the CQD dialogue and discussions active and informative in the spirit of the man himself, as he wanted.
NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. Visit NECA-NEIS.org for more information. NEISÃ” can be purchased in three formats: as paper books, on CD, or as electronic downloads.
NECA SAFETY PRODUCTS: NECA publishes valuable electrical safety books and CDs for the industry. Visit necanet.org/store to view or purchase NECA safety products.
CONTACT US: To submit a Code question, subscribe, or unsubscribe from this list, please e-mail: email@example.com.
© 1999 – 2014 National Electrical Installation Standards. All rights reserved.
Brought to you by NECA. NECA is the voice of the electrical contracting industry NATIONAL ELECTRICAL INSTALLATION STANDARDS, NEIS and the NEIS logo are registered trademarks of the National Electrical Contractors Association.
Created by Matrix Group International, Inc.