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National Electrical Code Top Ten Tips: Article 225 -- Outside Branch Circuits and Feeders

Based on the 2023 NEC

by Mark Lamendola

Please note, we do quote from copyrighted material. While the NFPA does allow such quotes, it does so only for the purposes of education regarding the National Electrical Code. This article is not a substitute for the NEC.

These are the 10 NEC Article 225 items we deem most important, based on the pervasiveness of confusion and the potential costs of same. An outside branch circuit or feeder is a branch circuit or feeder that runs between buildings (thus, it's outside the building where the service is, though it may or may not actually be outdoors).

  1. Read the scope carefully. In many instances of disagreement with the electrical inspector, folks are misapplying 225 [225.1].
  2. Table 225.3 clearly shows were other NEC Articles apply to specific equipment and conductors. For example, fire alarm systems are in Article 760.
  3. Overhead conductors outdoors must be insulated or covered (per Article 100, a covering is not insulation) when within 10 feet of a building. Except for Type MI cable, the insulation must be thermoset or thermoplastic type. In wet locations, it must comply with 310.10(C) [225.4].
  4. Prior to the 2023 NEC, 225.7 existed and it gave various rules for outdoor lighting. These rules have been moved out of Article 225. You will find them in Article 210. Article 225 modified them if they were outside and had a common neutral [225.7(B)], 277V [225.7(C)], or 1000V [225.7(D)]. Having these limitations in Article 210 (for example, 210.6(C) for 277V) where the other requirements are makes the NEC easier to use.
  5. 225.14 provides the rules for open conductor spacing. These have changed with the 2023 revision, so review them carefully.
  6. 225.18 is "Clearance for Overhead Conductors and Cables." This has often been a source of contention in court. Itís best to exceed the requirement by a foot or two, as design and installation are two different things and being off by an inch can burn you, despite the fact that itís substantial compliance and obviously satisfies the intent of the Code. For one thing, a crane operator wonít know you are an inch low, and that can get somebody killed. These are minimal heights. Pay attention to the type of area a cable will pass over, and use the highest clearance if in doubt. Also, create a clear path for fire ladder equipment and other emergency apparatus. Sometimes, simply locating the overhead conductors at the same height but 15 feet to the east (or wherever) reduces danger by orders of magnitude. Can you route to the backside of the building and avoid the (for example, walkway) altogether? Meeting clearance requirements doesn't ensure nobody will get electrocuted. Use a combination of measures, wherever possible.
  7. 225.19 gives the clearances from buildings (1000V or less) óthe comments I gave for 225.18 also apply here.
  8. You can have a single disconnect on a service or up to six [225.33]. But if you have more than one, you must group all of them (except a fire pump disconnect, which has special requirements) [225.34]. At a plant where we already had 6 disconnects on a entrance, my boss wanted me (as the plant electrical engineer) to play labeling and wiring games to get around the rule and actually have 7 disconnects. My boss' scheme involved using the switchgear as a pullbox to put the 7th disconnect on the other side so it wouldn't be seen when you're looking at the service entrance area. I explained to him the rule existed primarily for first responders. They know once they have opened 6 disconnnects, that part of their job is done. Hiding a switch from them would be a criminal act, not just a Code violation. I said if he wanted to add a 7th switch, I would do that but it would be visible at the entrance and I would clearly label each switch 1 of 7, 2 of 7, etc. After some discussion, we agreed to a solution that involved replacing the 30 year old switchgear with a new system that was badly needed and reducing the total number of switches to four. Keep that in mind if you are ever pressured to "forget" this rule.
  9. You must have a circuit directory or plaque (with some exceptions noted) to identify the circuits [225.37]. This is an issue most installers routinely ignore or inadequately comply with. The intent here is not to have vague text, but to clearly identify the circuits. This isnít just for the convenience of the owner or service tech. Itís also for the use of the first responders (e.g., for stopping an electrocution), fire department workers and other emergency workers. It is illegal to shirk responsibility here, and this particular violation can carry heavy personal penalties for all concerned. Some of the new products on the market make this job much easier and the outcome much better. Check with your panel supplier to see what's available.
  10. 225.60 and 225.61 provided more information on clearances, such as those over sidewalks. With the 2023 revision, they are gone. The 2023 revision removed Part III Over 1000 Volts, so Article 225 ends with 225.42. Where did this information go? The 2023 NEC contains the new Article 235 Branch Circuits, Feeders, and Services over 1000 Volts ac, 1500 Volts dc, Nominal.