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Infrastructure Codes and Standards-the National Electrical Code® and DC Power

Infrastructure Codes and Standards-the National Electrical Code® and DC Power

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Infrastructure Codes and Standards-the National Electrical Code® and DC Power

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  1. Infrastructure Codes and Standards-the National Electrical Code® and DC Power Mark W. Earley, P.E. Chief Electrical Engineer

  2. What is the National Electrical Code? • Also known as the NEC ® or ANSI/NFPA 70 • There are two electrical codes that govern electrical installation • The National Electrical Safety Code®-governs electrical and communications utility installations • The National Electrical Code®-governs electrical installations in the built environment

  3. History • First meeting held in 1896 • Five Codes in use in the USA at the time • Intended to promote safety and facilitate product standardization across the country • First edition issued in 1897 • NFPA became sponsor in 1911 and has continued to be the sponsor for 100 years • There have been 52 editions • Since 1953, the NEC has been issued every three years • Adopted into law

  4. Adoption of the NEC clipart provided by: www.worldatlas.com

  5. Adoption of the NEC clipart provided by: www.worldatlas.com

  6. Organization of NEC Project The NEC TCC has responsibility for 19 Code-Making Panels plus several other Technical Committees and documents, including NFPA 70B, 70E, 73, 79, 110, 111, 790, and 791.

  7. Other Applicable Standards • NFPA 70B-Electrical Equipment Maintenance • NFPA 70E-Electrical Safety in the Workplace • NFPA 79-Industrial Machinery • NFPA 110-Standard for Emergency and Standby Power Systems • NFPA 111- Standard on Stored Electrical Energy Emergency and Standby Power Systems • NFPA 790- Standard for Competency of Third Party Field Evaluation Bodies • NFPA 791- Recommended Practice and Procedures for Unlabeled Electrical Equipment Evaluation

  8. The Three Leg Stool • Electrical installation requirements--NEC® • Product standards -UL, NEMA, etc • Product testing to standards • Electrical inspection (ensures compliance with the installation rules of the NEC, along with any product installation requirements

  9. DC Requirements • Have been in every edition since the 1897 edition. • There are specific AC and DC requirements • Where not specified, requirements apply to AC and DC

  10. The NEC Applies to AC and DC AC Requirements DC Requirements AC Systems DC Systems

  11. Most Common DC Applications • Article 480 Batteries • Article 690 PV Systems • Article 725 Class 1, 2, and 3 Systems • Article 760 Fire Alarm Systems • Article 800 Communications

  12. Thoughts to Ponder • Are the Common Requirements a Good Idea? • Based on current applications, yes! • Based on current technology, the requirements of the NEC have worked well. • Higher power DC may present new challenges • Overcurrent protection • GFCI protection • AFCI protection • Switching • Circuit protection • Arc flash evaluation • Circuit separation

  13. Thoughts to Ponder • Standard nominal AC line voltages • 120/240 Volts single phase • 208Y/120 Volts three phase • 480Y/277 Volts three phase • Standard nominal DC Line voltages • ? • 380 volts • Demand factors • Plug and receptacle configurations?

  14. Thoughts to Ponder • If DC is produced by switching mode supplies, will there be nonlinear load problems? • Neutral conductor size for AC services, feeders, and branch circuits • Electronic noise • Isolated grounding

  15. NEC TCC Task Group on DC • Chaired by John Kovacik, UL • Members from various parts of the NEC community • May be soliciting additional members with DC expertise

  16. The NEC has an Open Process • Anyone can submit a proposal or public comment • Committee meetings are open • Anyone can request time to address a code-making panel • Committee reports are published

  17. Critical Points in NEC Processing Schedule Comment Closing Proposal Closing Date NEC TCC Meeting Nov. 4, 2011 Jan. 9-21, 2012 April 23-27, 2012 June 15, 2012 Oct. 17, 2012 Nov 28-Dec 8, 2012 CMP ROP Meetings. CMP ROC Meetings. ROP Published Note: The Individual CMP meeting dates have not yet been established.

  18. Thank you! It can’t happen without your input!