The word “accessible” appears many times in NFPA 70E and even more times in NFPA 70. When equipment is “accessible,” that means a person can get physically close to it without facing any effective barriers, such as locked doors or elevation. A motor disconnect must be “readily accessible” per Sec. 430.107, but there’s no such requirement for the OCPD supplying that motor. In fact, it’s typically not accessible. If you think about the purpose of each of these devices, the logic between making one accessible and the other not is fairly clear.
If your boss okays the use of tubing fittings to assemble conduit, is that an approved use? It may be approved by your boss, but in the sense intended by NFPA 70, NFPA 70B, and NFPA 70E, it’s not “approved.” It has to be acceptable to the Authority Having Jurisdiction (AHJ). Commercial and industrial properties may have multiple AHJs, such as the fire marshall, the city engineer, the electrical inspector, the serving utility, and/or the company’s insurer. Any one of these parties can shut the facility down in part or in whole.
If, for example, you run parallel feeders that are two different sizes and the utility’s field engineer or field electrician sees that, you will likely be served with a notice to shut down. Based on the field person’s judgment, they will maybe cut you a little slack. If the jacket insulation is melted back 6 in., the conductors are discolored, but there’s no smoke (yet), the utility might give you 30 minutes for an orderly shutdown. But if there’s no visible damage (yet), they may or may not allow you a few days.
Don’t think of AHJ narrowly, or as necessarily a plant-wide factor. While not technically AHJs for the purposes of NFPA 70, NFPA 70B, and NFPA 70E, there are outside companies whose requirements you may have to meet for specific equipment (or operation of it) to be “approved”. For example, an annealing furnace or large boiler may be subject to AHJs of their own (e.g., the Hartford Boiler Company) as a condition of operation. Equipment warranties may also depend upon meeting specific requirements (e.g., special grounding considerations, operator certifications, specific specialized testing, etc.).
How can you ensure your work and materials are “approved”? Generally, an AHJ will demand compliance with the relevant part of the NEC. If you find that compliance is going to create an impractical situation, don’t just go ahead with an alternative version. Think about the intent of the relevant Code requirements, write a concise explanation, and provide any drawing(s) that will help. Then work it out with the AHJ to get approved before proceeding with the work.
Sometimes the AHJ will add a requirement that is not in the NEC. You can point this out and ask for the requirement to be stricken or modified, but the AHJ is not constrained by the NEC. Always keep in mind the AHJ is not your peer. This person is an authority, and you must show respect for that person and the office that person holds.
