Attention Fast Trax® Friends and Family - Registration is FREE.

Minimum Number of Branch Circuits Required for one-Family Dwellings.

In this forum you can Read and Post Blogs of electrical interest. You can also comment on the blogs and share your thoughts for others to gain and learn. However, any violation of the posting rules will result in account termination and banning from this forum.

Rules :

1) No Copyright Infringement - Post YOUR original content only!
2) Any posting of crude, violent, or misleading information will result in a ban from the forum.
3) No marketing promotions for Electrical Educators or Electrical Training Material other than ECA, Inc.

Moderator: Swartz09

Post Reply
User avatar
Site Admin
Posts: 235
Joined: Tue Dec 27, 2022 5:17 pm
Location: McKinney, TX

Minimum Number of Branch Circuits Required for one-Family Dwellings.

Section 210.11 contains provisions for determining the minimum number of branch circuits, including the requirements for small-appliance branch circuits, laundry branch circuits, bathroom branch circuits, and garage receptacle circuits.

Per 210.11(B), the required branch circuits shall be evenly divided across the branch-circuit panelboard. In addition, branch-circuit overcurrent devices and circuits need only be provided for connected loads. Any future loads need not be considered. See 210. 11 (A through C).

To find the required number of circuits for the lights and general-purpose receptacles, first determine the current for the lighting and receptacle circuits. To find the current, multiply 3 VA/sq ft by the square footage of the dwelling. This is the total load in volt-amps. Divide the total volt-amps by the voltage, which is usually 120 V. This determines the current for the light and receptacle circuits. The current is then divided by the size of the overcurrent protective device, which is usually a 15 A or 20 A circuit breaker, to determine the required number of circuits. If the answer comes out to be a decimal, always round up to a whole number for example, how many 20 A, 120 V circuit breakers are required for an 2100 sq ft dwelling?

Step 1: Number of circuit breakers = 3 VA/sq ft x area of dwelling / Voltage

Then = Sum of Step 1 is divided by the circuit breaker rating.

In our example :

3 VA x 2100 = 6,300 / 120 = 52.5

Next, 52.5 is divided by the branch circuit rating : 52.5 / 20 = 2.625 and you can’t have .625 of a circuit so you would round this to (3) circuit breakers needed.

Note: This has nothing to do with the required additional branch circuits as describe din 210.11(A) through (C).

*Based on the 2023 National Electrical Code
Best Regards,

Paul W. Abernathy, CMECP®
Fast Trax® System
Electrical Code Academy, Inc.
Post Reply