NEC · Article 210

Branch Circuits

A branch circuit is the last leg of the electrical system — from the final overcurrent device to the load — and Article 210 governs everything about it, from allowable ratings to the specific circuits every dwelling must have.

NEC 2017 2020 2023 Last updated 2026-06-27

What a branch circuit is — and where it starts

The NEC defines a branch circuit as the conductors between the final overcurrent device protecting the circuit and the outlets it supplies. That boundary matters: the instant you cross from the downstream side of the last breaker or fuse to the first outlet or load, you are in branch-circuit territory and Article 210 applies. Everything between the service equipment and that final overcurrent device is a feeder, governed by Article 215.

Journeyman exam questions on branch circuits almost always start by testing whether you can draw that line correctly. A circuit with two panelboards in series has a feeder feeding the second panel and branch circuits leaving it — the location of the last overcurrent device is what decides which rules apply.

Types of branch circuits

Article 210 recognizes four branch-circuit types, and knowing them by name helps on exam questions that ask which rules apply:

  • General-purpose branch circuit — serves two or more outlets for lighting and appliances. The standard residential 15- and 20-amp circuits that serve living areas fall here.
  • Appliance branch circuit — supplies one or more outlets that are intended only for appliances. Lighting outlets are not permitted on these circuits. The kitchen small-appliance circuits described below are a specific required form of appliance branch circuit.
  • Individual branch circuit — supplies only a single piece of utilization equipment. A dedicated circuit for a clothes dryer, range, or air conditioner is an individual branch circuit, and it must be sized for the load it serves.
  • Multiwire branch circuit (MWBC) — uses two or more ungrounded conductors that share a common neutral, each connected to a different leg of the supply so the neutral carries only the unbalanced current. In practice, a 240/120-volt circuit with two hots and one shared neutral is the common dwelling form. Recent editions require that a multiwire branch circuit be controlled by a single multi-pole disconnect, so all conductors of the circuit open together.

Standard branch-circuit ratings

Section 210.3 lists the allowable ratings for branch circuits that serve two or more outlets: 15, 20, 30, 40, and 50 amperes. A circuit at any of those ratings can supply multiple outlets. Individual branch circuits — those that serve only a single load — are not limited to that list and can be any size needed for the equipment.

Rating Minimum conductor (copper, 60/75 °C terminal) Typical use
15 A 14 AWG General lighting, receptacles
20 A 12 AWG Kitchen/bath receptacles, small appliances
30 A 10 AWG Clothes dryers, air conditioners
40 A 8 AWG Ranges, large HVAC
50 A 6 AWG Ranges, EV charging (individual circuits)

These minimum conductor sizes come from 310.12 for dwelling units and the ampacity tables for other occupancies. Always verify against the termination temperature rating of the equipment — most residential panels list 60°C or 75°C terminals, which controls which column of the ampacity table you use.

Required branch circuits in a dwelling unit

The NEC does not leave it to the designer to decide whether certain circuits exist. Section 210.11 mandates specific branch circuits in every dwelling unit:

  • Small-appliance circuits (210.11(C)(1)): At least two 20-ampere branch circuits must supply the receptacle outlets in the kitchen, dining room, pantry, and similar areas. These circuits may not serve lighting outlets or other loads, and they must be 20-ampere rated (12 AWG conductors minimum).
  • Laundry circuit (210.11(C)(2)): At least one 20-ampere branch circuit is required to supply the laundry receptacle outlet. This circuit may not serve other outlets (unless the laundry area is also used as a living space in specific dwelling types).
  • Bathroom circuit (210.11(C)(3)): At least one 20-ampere branch circuit must supply the bathroom receptacle outlet(s). That circuit may serve more than one bathroom, or it may be dedicated to a single bathroom — but if it serves only that bathroom's receptacles, it can also serve other outlets within that same bathroom.

These are minimums. An exam question may ask what the code requires, not what a good design would add. Knowing that the small-appliance circuits must be 20-ampere, must supply only those areas, and that at least two are needed is the core fact to lock in.

Branch-circuit conductors and overcurrent devices must also account for continuous loads — any load expected to run for three or more hours must have the conductor and breaker sized at 125 percent of that load. That rule from 210.19 and 210.20 applies at the branch-circuit level the same way it does to feeders.

Practice questions on this rule

Real journeyman-exam practice questions from Loomi's bank — answer first, then reveal the explanation.

Q1 NEC 210.23(B)

A dwelling unit's required laundry branch circuit under 210.11(C)(2) is being installed. What may this circuit supply?

  1. A The laundry receptacles plus general lighting in the same room
  2. B The laundry receptacles plus fastened-in-place equipment up to 50 percent of the circuit rating
  3. C The laundry receptacles plus any cord-and-plug load up to 80 percent of the circuit rating
  4. D Only the receptacle outlets specified in that section
Show answer & explanation

Correct: D — Only the receptacle outlets specified in that section

210.23(B) states that the small-appliance, laundry, and bathroom branch circuits required by 210.11(C)(1) through (C)(3) shall supply only the receptacle outlets specified in that section — they don't get mixed with lighting or the general 80/50 percent allowances that apply to ordinary 15/20 A circuits.

Q2 NEC 210.23(C)

Per 210.23(C), what is the maximum percentage of a 30-ampere branch circuit's rating that one cord-and-plug-connected utilization equipment may draw?

  1. A 50 percent
  2. B 80 percent
  3. C 100 percent
  4. D 125 percent
Show answer & explanation

Correct: B — 80 percent

210.23(C) caps any single cord-and-plug-connected utilization equipment at 80 percent of the branch-circuit rating. The 100 percent option ignores the cap entirely, 50 percent is the fastened-equipment fraction used elsewhere in 210.23 (not this rule), and 125 percent is a continuous-load sizing factor, not a load limit.

Q3 NEC 210.23(C)

A 30-ampere branch circuit is being installed in a single-family dwelling to serve fixed lighting units with heavy-duty lampholders. Is this permitted under 210.23(C)?

  1. A Yes, but only with GFCI protection
  2. B No, because 210.23(C) permits that lighting use only in occupancies other than dwelling units
  3. C No, because 30-ampere circuits cannot supply lighting in any occupancy
  4. D Yes, because a 30-ampere circuit permits any lighting load in any occupancy
Show answer & explanation

Correct: B — No, because 210.23(C) permits that lighting use only in occupancies other than dwelling units

210.23(C) limits fixed heavy-duty-lampholder lighting on a 30-ampere circuit to occupancies other than dwelling units, so a single-family dwelling doesn't qualify. The 'any occupancy' option overstates the permission, GFCI protection isn't the deciding factor here, and the claim that 30A circuits can never supply lighting ignores the non-dwelling permission the section actually grants.

Q4 NEC 210.11(C)(3)

A dwelling has one bathroom, supplied by a single 20-ampere, 120-volt branch circuit. Which of the following is permitted on that circuit?

  1. A General lighting outlets in the adjacent bedroom
  2. B A countertop receptacle outlet in the kitchen
  3. C Receptacle outlets in a second bathroom down the hall
  4. D The bathroom's exhaust fan, per 210.23(B)(1) and (B)(2)
Show answer & explanation

Correct: D — The bathroom's exhaust fan, per 210.23(B)(1) and (B)(2)

Under 210.11(C)(3), when the 20-ampere circuit supplies a single bathroom, other equipment within that same bathroom — such as the exhaust fan — may be supplied by it per 210.23(B)(1) and (B)(2). Outlets in a second bathroom, the kitchen, or an adjacent bedroom fall outside 'the same bathroom' and are not covered by the exception.

All Branch Circuits practice questions (Article 210)

Frequently asked questions

What is a branch circuit?
A branch circuit is the conductors that run from the final overcurrent device in a panelboard out to the outlets and loads it serves. Everything upstream of that last breaker or fuse — between the service and that overcurrent device — is a feeder, not a branch circuit.
How many small-appliance branch circuits does a dwelling require?
At least two 20-ampere small-appliance branch circuits are required for the kitchen, dining, and pantry areas of a dwelling under 210.11(C)(1). Those circuits must supply only the receptacle outlets in those areas and cannot serve lighting outlets or other loads.
What is a multiwire branch circuit?
A multiwire branch circuit shares a neutral among two or more hot conductors that are connected to different legs of a multi-phase system. In a dwelling, a common form is a 240/120-volt two-pole circuit with two hots and one neutral. The NEC requires that a multiwire branch circuit be disconnected simultaneously at the panel.
Related articles
Feeders (Article 215) How feeders differ from branch circuits and how they are sized. Continuous Load & the 125% Rule Applying the 125% factor to branch-circuit conductors and breakers. AFCI Protection Which branch circuits in a dwelling require arc-fault protection. How Many Outlets on a Circuit? What the NEC says (and does not say) about receptacle counts.
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