Dwelling Receptacle Spacing: The 6 and 12 Foot Rule

Why this matters

The general receptacle rule exists so nobody runs an extension cord across a doorway, and it is where rough-in layouts get caught on the details: a 2 ft stub of wall between a slider and a fireplace that nobody boxed, a fixed glass panel that counts as wall but cannot take a box, a receptacle switched for the room light that the layout counted on. NEC 210.52(A) (NEC 2023, 2020 where the section moved, as adopted, local amendments checked) is short, and what makes it work in the field is knowing exactly what counts as wall space and what counts as a receptacle. This card owns that, plus hallways and the outdoor receptacles at grade under 210.52(E). Countertops are their own rule; see 'Countertop Receptacle Spacing Rules'.

Adding a box in an existing room means cutting into a circuit: breaker off, locked and tagged, and absence of voltage verified with a CAT III or better meter proven on a known live source before and after (NFPA 70E Article 120, current edition; 29 CFR 1910.333(b)(2)). When the new receptacle is trimmed, restore the breaker and confirm it and the rest of the circuit with a plug-in tester.

The rule and its arithmetic

In substance (210.52(A)(1), check the current edition): in every kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedroom, recreation room or similar room or area of a dwelling unit, receptacles are installed so that no point measured horizontally along the floor line of any wall space is more than 6 ft from a receptacle outlet.

The arithmetic a crew carries:

• One receptacle serves at most 12 ft of floor line, 6 ft on each side.
• A receptacle within 6 ft of each end of a wall space, and no more than 12 ft between neighbors. That is where the "6 and 12" name comes from.
• The minimum count for a space of length L is L divided by 12, rounded up. A 24 ft space can be done with two receptacles placed exactly right (at 6 ft and 18 ft); a 25 ft space needs three.

The rule is measured space by space. A receptacle on the far side of a doorway does not serve the wall on this side, however close it is, because the doorway ends the wall space.

What counts as wall space

From 210.52(A)(2), in substance:

• Any wall 2 ft or wider, measured along the floor line and around corners, and unbroken by doorways and similar openings, fireplaces, and fixed cabinets that do not have countertops or similar work surfaces.
• Fixed panels in exterior walls, such as a fixed glass panel in a window wall. Sliding panels are excluded. The fixed half of a sliding door unit is commonly treated as a fixed panel; ask the AHJ if the layout depends on it.
• Fixed room dividers, such as a freestanding bar-type counter or a railing.

What breaks it: a doorway, a fireplace, a sliding panel, a built-in bookcase or cabinet with no countertop. A corner does not break it.

The 2 ft space is the one that gets missed. A 2 ft stub of wall is a wall space and needs a receptacle within 6 ft of every point on it. Since the receptacles on the other sides of its doorway or fireplace do not count, in practice that means a box on the stub itself.

What counts as a receptacle

Not every receptacle in the room counts toward spacing. In substance, from 210.52 and 210.52(A)(3) and (A)(4):

• Does not count: a receptacle that is part of a luminaire or appliance; one inside a cabinet or cupboard; one more than 5.5 ft above the floor; a receptacle switched to serve as the room's required lighting outlet under 210.70 (the common reading; confirm your edition's wording and the AHJ); and countertop receptacles, which serve the countertop rule only.
• Floor receptacles count only within 18 in of the wall. This is how a fixed glass wall gets served: a floor box close to the glass.
• A split-wired receptacle with one half switched is the usual answer where a room uses a switched receptacle for lighting: the unswitched half stays on the floor-line layout. Wiring it is owned by 'How to Wire a Switched Half-Hot Living Room Receptacle'; confirm the AHJ reads it the same way before the layout depends on it.

Hallways and foyers

• Hallways 10 ft or longer get at least one receptacle (210.52(H)). Length is measured along the centerline of the hall without passing through a doorway, so an L-shaped hall is measured around its bend.
• Foyers that are not part of a hallway and are larger than 60 sq ft get a receptacle in each wall space 3 ft or wider (210.52(I), in substance). Doorways, door-side windows that extend to the floor, and similar openings do not count as wall space there.

Outdoor receptacles at grade

From 210.52(E), in substance:

• One-family dwellings, and each unit of a two-family dwelling at grade level: at least one receptacle at the front and one at the back, readily accessible from grade and not more than 6.5 ft above grade.
• Multifamily units with their own entrance at grade: at least one receptacle readily accessible from grade, not more than 6.5 ft above grade.
• Balconies, decks and porches accessible from inside the unit: at least one receptacle within the perimeter of the balcony, deck or porch, not more than 6.5 ft above its walking surface.

A receptacle on the back deck 9 ft above the yard satisfies the deck rule and not the back-at-grade rule, so a raised deck house usually owes both. GFCI and WR requirements for those receptacles are in 'AFCI and GFCI by Location in a Dwelling' and 'Tamper-Resistant and Weather-Resistant Receptacle Rules'.

Worked example: one living room

The room. The floor line is unfolded below as a single line, starting at the left jamb of the entry door (jamb A) and running around the room to its right jamb (jamb B). Feet along the floor line from jamb A:

• 0 to 4 ft: wall to the first corner.
• 4 to 20 ft: wall to the second corner.
• 20 to 25 ft: fixed glass panel in the window wall.
• 25 to 30 ft: sliding glass panel.
• 30 to 32 ft: 2 ft of wall.
• 32 to 38 ft: fireplace.
• 38 to 41 ft: wall to the third corner.
• 41 to 54 ft: wall to jamb B.

      R1     R2     R3          R4          R5     R6
       o      o      o           o           o      o
  |---+---------------+====|::::|-#######--+------------|
JAMB A               FIXED SLIDE  FIREPLACE        JAMB B
  0                  20        30      38              54
      4                   25     32       41

FEET ALONG THE FLOOR LINE FROM JAMB A, UNFOLDED
+ ROOM CORNER   = FIXED GLASS   : SLIDING PANEL
# FIREPLACE     o RECEPTACLE OUTLET

Find the wall spaces. Corners do not break a space; the slider and the fireplace do.

• W1, 0 to 25 ft: 4 plus 16 plus the 5 ft fixed panel, 25 ft. The fixed panel counts.
• W2, 30 to 32 ft: 2 ft between the slider and the fireplace. It is 2 ft, so it counts.
• W3, 38 to 54 ft: 3 plus 13, 16 ft.

Size each space. 25 divided by 12 is about 2.1, so W1 needs three. W2 needs one. 16 divided by 12 is about 1.3, so W3 needs two. Six in all.

Place and check them.

• W1: R1 at 5 ft, R2 at 12 ft, R3 at 19.5 ft, just short of the glass. Jamb A is 5 ft from R1. R1 to R2 is 7 ft and R2 to R3 is 7.5 ft, both under 12. The end of the fixed panel at 25 ft is 25 minus 19.5, 5.5 ft from R3. Every point passes 6 ft, and no box goes in the glass.
• W2: R4 at 31 ft, the middle of the stub. Each end is 1 ft away.
• W3: R5 at 43 ft, R6 at 50 ft. The fireplace edge at 38 ft is 43 minus 38, 5 ft from R5. R5 to R6 is 7 ft. Jamb B at 54 ft is 54 minus 50, 4 ft from R6.

Six receptacles, each at the usual 12 to 18 in above the floor, none more than 5.5 ft up, none switched.

The rest of the same house. The hall outside the room is L-shaped: 8 ft along its centerline to the bend and 6 ft beyond it, 14 ft measured without passing through a doorway, so it owes one receptacle. Outside, the house sits on a slope with a deck off the kitchen 9 ft above the back yard. The front gets one receptacle beside the door at about 18 in above grade. The deck gets one within its perimeter at deck-rail height, well under 6.5 ft above the decking. The back-at-grade rule is not met by the deck receptacle, which is 9 ft above the yard plus its own mounting height, so a third goes on the foundation wall under the deck, readily accessible from the yard and under 6.5 ft above grade. Three outdoor receptacles, where a house with its deck at grade can usually let one deck receptacle serve both rules and stop at two.

What moves the answer

Each of these changes a different input to the same room:

• The fixed glass panel is 7 ft instead of 5 ft. W1 grows to 27 ft and its end sits 27 minus 19.5, 7.5 ft from R3, which fails. A box cannot go in the glass, so the fix is a floor receptacle within 18 in of the glass at about 23 ft, which then covers from 17 ft to 29 ft.
• The slider unit is 4 in wider and W2 shrinks to 20 in. Under 2 ft, it is not a wall space and owes no receptacle. R4 drops out.
• The owner wants R2 switched as the room's lighting outlet. Read the usual way, a receptacle switched as the required lighting outlet does not count, and the gap from R1 at 5 ft to R3 at 19.5 ft becomes 14.5 ft, over 12. Split-wire R2 so its unswitched half stays in the layout, or add a receptacle.

Catching it at rough-in

• Unfold the room on paper first, the way the example does, before anyone drills. Corners vanish and the breaks stand out.
• Box every stub 2 ft or wider, even where it looks pointless. Check behind where a slider, a fireplace surround or a built-in will land on the finished drawing, not where the framing is today.
• Write each receptacle's distance on the stud at rough-in. An inspector with a tape checks the layout in a few minutes, and nobody argues later about what was planned.

References

• NFPA 70, National Electrical Code, 210.52(A), (E), (H) and (I), 210.70 (NEC 2023, 2020 where the section moved), as adopted by your jurisdiction.
• NFPA 70E, Article 120 (current edition); 29 CFR 1910.333(b)(2).
• See related: Countertop Receptacle Spacing Rules; How to Wire a Switched Half-Hot Living Room Receptacle; Required Lighting Outlets and Switch Locations.