Show Window Receptacle Outlet Calculator
Count the receptacle outlets a show window requires under NEC 210.62: one 125 V, 15 or 20 A receptacle within 18 in of the top of the window for each 12 linear feet, or major fraction thereof, measured horizontally at the maximum width. Enter the window width and the tool returns the required count and the placement rule.
How to use this calculator
- Measure the show window horizontally at its maximum width and enter the width in linear feet.
- Read the required receptacle count: one for each 12 linear feet, plus one more for a leftover major fraction of 6 feet or more.
- Place each receptacle within 18 inches of the top of the window; it is a 125 V, 15 or 20 A receptacle.
- Evaluate each separate show window individually at its own maximum width, then add the counts.
- For the show window load, not the receptacle count, use the Show Window & Sign Lighting Load Calculator.
NEC reference
This calculator implements National Electrical Code (NEC) 2020 210.62 (Show Windows). It requires at least one 125-volt, single-phase, 15- or 20-ampere-rated receptacle outlet to be installed within 450 mm (18 in.) of the top of a show window for each 12 linear feet (3.7 m) or major fraction thereof of show window area measured horizontally at its maximum width. The Article 100 definition of a show window includes the window above a door. NEC 2020 is the site default; the 2023 edition replaced the per-12-foot method with a no-point-farther-than-6-feet rule, noted below.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.
The 210.62 count, step by step
Section 210.62 counts receptacles by the width of the show window. Divide the width by 12 feet. Every full 12-foot segment gets one receptacle, and a leftover piece gets one more only if it is a major fraction, which the trade reads as 6 feet or more. A leftover under 6 feet adds nothing. The receptacle count is a requirement for the window itself, separate from the branch-circuit load the window adds.
| Show window width | Full 12 ft segments + remainder | Required receptacles |
|---|---|---|
| 12 ft | 1 + 0 ft | 1 |
| 17 ft | 1 + 5 ft (minor) | 1 |
| 18 ft | 1 + 6 ft (major) | 2 |
| 20 ft | 1 + 8 ft (major) | 2 |
| 24 ft | 2 + 0 ft | 2 |
| 30 ft | 2 + 6 ft (major) | 3 |
Where the receptacle goes
Each required receptacle is installed within 18 inches of the top of the show window, not down at the base. A receptacle in or around the show-window floor does not satisfy 210.62. The receptacle is a 125-volt, single-phase, 15- or 20-ampere device. The 2020 text does not fix a mounting height beyond the 18-inch rule, nor does it state whether the receptacle is on the inside or outside of the glass, so the designer places it to serve the display while meeting the 18-inch dimension.
Receptacle count vs. show window load
Two different NEC rules use the show window width, and they are easy to confuse. Section 210.62 counts the required receptacle outlets, which is what this tool does. Sections 220.14(G) and 220.43(A) compute the show window load at 200 volt-amperes per linear foot of show window, added to the branch circuit and to the feeder or service calculation. A 20-foot show window needs 2 receptacles under 210.62 and adds 20 × 200 = 4000 VA of load under 220.14(G). Use the Show Window & Sign Lighting Load Calculator for the load figure.
Worked examples
A 20-foot storefront display window: 20 / 12 is one full 12-foot segment with an 8-foot remainder. Eight feet is a major fraction of 12, so it adds one receptacle, for a total of 2 receptacles, each within 18 inches of the top of the window.
A 30-foot display window: two full 12-foot segments is 24 feet, leaving a 6-foot remainder. Six feet is exactly a major fraction, so it adds one receptacle, for a total of 3.
A narrow 5-foot show window: no full 12-foot segment and a 5-foot minor fraction, so the literal 2020 arithmetic gives 0 required receptacles. The 2023 NEC and many inspectors require at least one receptacle for any show window, so confirm with the authority having jurisdiction.
Common mistakes
- Mounting at the base. The receptacle goes within 18 inches of the top of the window. A floor receptacle does not count.
- Rounding a minor fraction up. A leftover under 6 feet adds no receptacle. A 17-foot window needs one, not two.
- Using the load rule for the count. The 200 VA per foot figure is the show window load (220.14(G)), not the receptacle count (210.62).
- Ignoring the window above the door. The Article 100 definition includes it in the show window width.
- Treating several windows as one length. Each separate show window is counted on its own maximum width.
Frequently asked questions
How many receptacles does a show window need?
One for each 12 linear feet or major fraction thereof of the window width, measured at the maximum width (210.62). A major fraction is 6 feet or more.
Where does the receptacle go?
Within 18 inches of the top of the show window, a 125 V, 15 or 20 A receptacle. A floor receptacle does not satisfy 210.62.
What is a major fraction of 12 feet?
Six feet or more. A 6-foot leftover adds a receptacle; a 5-foot leftover does not.
Does a window under 6 feet need a receptacle?
By the literal 2020 per-12-foot rule, no. The 2023 NEC and many AHJs require at least one receptacle serving any show window, so confirm with the authority having jurisdiction.
Is this the same as the show window load?
No. This counts receptacle outlets (210.62). The load is 200 VA per linear foot (220.14(G)), handled by the Show Window & Sign Lighting Load Calculator.
Related calculators
- Show Window & Sign Lighting Load Calculator: the 200 VA per foot show window load and the 1200 VA per sign circuit for a feeder or service calculation.
- Sign & Outline Lighting Outlet Requirement Calculator: when 600.5 requires a sign outlet, how many, and the dedicated 20 A circuit rule.
- Receptacle Spacing Calculator: the dwelling receptacle spacing rule (210.52), the companion to the show window rule.
- Commercial Receptacle Load Calculator: the general-use receptacle load per 220.14(I) and Table 220.44.
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