National Electrical Installation Standards

Standards as High as Your Own

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Tuesday, January 1, 2019

Question:

Re: CQD answer published Monday, December 17, 2018 -Vehicle Electrical Systems

Regarding the NEC and vehicular-mounted power outlets. My personal opinions are:

1) The position I believe that CMP 12 is taking regarding this issue is that 90.1 requires us to consider these situations, and that the NEC does indeed cover them.

2) A power outlet provided on a vehicle for use while the vehicle is not in motion, makes the outlet a necessary subject of the NEC. For this use, the "vehicle" is no longer a mobile piece of equipment - a "vehicle" - and has become a "generator." The electrical power available can certainly present significant hazards to life and property.

3) Since these power outlets could easily be up to 120/240-volts, 50-amps, I think that rules should be present in the NEC to address the outlets which can provide dangerous levels of power. I doubt that we are concerned about "cigarette lighter" power levels.

4)  Since these outlets are specific to equipment whose primary purpose is vehicular transportation, I think that the EV Article 625, rather than 445 Generators, will be the best suited for rule-making. The technical methods of power production from a vehicle will be significantly different than those of a purpose-built generator.

Scott Cline

A

Answer:

Hey Scott thanks for your comments and personal insight about what NEC Code Making Panel 12 is doing. You are correct 90.1(A) states the NEC purpose is the "practical safeguarding of persons and property from hazards arising from the use of electricity" but it only applies within the Scope of 90.2, which still excludes automotive vehicles in 90.2(B)(1). A second revision to the 2020 NEC (SR 7891) was created to add list item (6) to 90.1(A) - "Installations used to export electric power from vehicles to premises wiring or for bidirectional current flow". The committee statement is: "List item (6) clarifies that installations used to export electric power from vehicles is under the purview of the NEC ©. This is also consistent with the actions of CMP-12 and the revised scope of Article 625."

Looking at some CMP12 changes, 625.1 was changed by SR 7776 to include conductors and equipment connecting electric vehicles to premises wiring. A change to the definition of Electric Vehicle Power Export Equipment in 625.2 now includes the outlet on the vehicle, above specific voltage levels, that is used for loads external to the vehicle.

We need to keep in mind that the entire process for the 2020 NEC is not complete yet so these changes are not necessarily final but do give us some insight about future rules. nfpa.org/70next

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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.

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