National Electrical Code Top Ten Tips: Article 210 -- Branch Circuits

by Mark Lamendola

Based on the 2026 NEC

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 210 items we deem most important, based on the pervasiveness of confusion and the potential costs of same.

1. This Article was heavily revised with the 2026 revision. For example, Table 210.3, which identifies specific-purpose branch circuits, was moved to another article and renamed.
   
2. 210.4 Multiwire Branch Circuits. This is a circuit that "consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit, and that is connected to the neutral or grounded conductor of the system" [100]. The conductors of such circuits must originate from the same panel. These circuits can supply only line-to-neutral loads.
    
3. 210.8 Ground-Fault Circuit-Interrupter Protection for Personnel. Crawl spaces, unfinished basements, and boathouses are just some of the many locations requiring GFCI protection. If you don’t know the others, you’ll find out what they are in 210.8. There are 16 identified in "Other Than Dwelling Units" alone (up from the 10 listed in the 2023 revision). Many designers and installers try to see where they don't have to install a GFCI. But for the small price, a better approach is to use GFCI protection wherever there's a shock hazard for users of 120V branch circuits. For example, you don't need a GFCI on a convenience receptacle in a living room. Put one there anyway. If you adopt this practice, you'll cover all bases and never inadvertently create a Code violation by leaving out a GFCI where the Code does require it.
    
4. 210.11. Branch Circuits Required. With three subheadings, 210.11 gives summarized requirements for the number of branch circuits in a given system, states that a load computed on a VA/area basis must be evenly proportioned, and covers rules for dwelling units. But also apply some common sense. The idea behind these rules is to prevent overloading circuits due to not having enough for the loads that will likely be used. It's not feasible for the Code-making panels to provide a design. If adding another circuit will reduce the chances of overloading, add another circuit. For example, if you have a large kitchen it could make sense to have two circuits for the convenience receptacles instead of one. This does not mean that putting in two circuits per bathroom is a good idea, as that isn't going to reduce the chances of overloading because there just isn't that much load. Adding a circuit before the drywall goes up takes very little effort. After the drywall goes up, adding a circuit is far more time-consuming and expensive.
    
5. 210.12. Arc-Fault Circuit-Interrupter Protection. An AFCI provides "protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected" [100]. It is not a GFCI, though combination units do exist. The purpose of an AFCI (30 mA) is to protect equipment. The purpose of a GFCI (4 to 6 mA) is to protect people. With the 2023 revision, the requirements for AFCI have been heavily updated. And with the 2026 revision, they have again been heavily udpated.
    
6. 210.19. Conductors—Minimum Ampacity and Size. The rules for ampacity require some study. One item many people overlook is that branch conductors—before the application of any adjustment or correction factors—must have "an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load." The Code does have an exception for this, but the rule generally applies.
    
7. Table 210.21(B)(2) shows that the maximum load on a given circuit is 80% of the receptacle rating and circuit rating (not spelled out that way, but look at the numbers and do the math). The maximum load on a 20A OCPD is 16A (as the table shows). Thus, if you are planning to supply 20A on one circuit, that circuit must be at least 30A (next available size up OCPD from 20A).
    
8. 210.23 Permissible Loads. With the 2026 revision, this now breaks down by circuit size: 10A, 15A and 20A, 30A, 40A and 50A, and >50A in 210.23(A), (B), (C), (D), and (E) respectively. The rules make sense. For example, 10A circuits are limited to lights and exhaust fans (think bathrooms) while 40A and 50A circuits can supply cooking appliances that are fastened in place.
    
9. Table 210.24(1) Summary of Branch-Circuit Requirements allows you to see everything at a glance (for copper conductors; same thing applies for Table 21024(2) when using aluminum or copper clad conductors). You just look up the circuit rating (which you will base on the load you plan to supply), and the table tells you the minimum conductor size. For that circuit rating, it also tells you the size of the taps, overcurrent protection, and maximum load. It also tells you which lampholders are permitted, and what the receptacle rating must be. Don’t leave home without it!
    
10. 210.52. Dwelling Unit Receptacle Outlets. An area rife with confusion is receptacle spacing. "Receptacles shall be installed so that no point measured horizontally along the floor line in any wall space is more than 1.8 meters (6 feet) from a receptacle outlet" [210.52(A)(1)]. This means you can’t have receptacles more than 12 feet apart along a wall line. 210.52 notes certain exclusions, describing what a wall space is and is not. You can exceed this requirement by mounting two receptacles to every stud, if you so desire. But, you cannot space them any less than 12 feet apart along a wall as defined by the NEC. Note, doorways and certain other items do not count in the 12 feet.
    
    Meeting this requirement doesn't necesarily mean you did a good job. This requirement is woefully inadequate for the typical dwelling, but with so many atypical applications it simply is not possible to require X receptacles per Y space. Many seemingly good proposals have failed to pass the test of feasible universal application. So we are stuck with minimums that don't really meet the minium requirements for a good installation. This issue is why we have the statements in 90.2(B). You are not expected to use the Code as an excuse for inadequate design, because good design is not the intention of the Code. Too many installers forget this when it comes to providing receptacles.
    
    Consider the paucity of receptacles in the typical bathroom; this usually means the occupant must run cords across the sink or vanity. Yes you can get by with doing that, but is doing such shoddy work why you became an electrician? Go beyond the Code requirement and imagine where loads will actually be used in a given room. Installing a receptacle placed to service those loads is part of doing a good job. If you stop and think about it, 3 duplex receptacles in a modern typical bathroom means underserving that room. The Code requires only one, but caring about how the occupant will actually use that space requires at least 4. It's not the 1950s anymore, install receptacles accordingly.