Missouri Electrical Code: Outlet Spacing in Residential Rooms

In every habitable room — living room, bedroom, den, hallway over 10 feet — no point measured along the floor line of a wall can be more than 6 feet from a receptacle. The reasoning: a standard appliance cord is 6 feet, so you should never have to run a cord across a doorway. In practice this means outlets go at the ends of walls (within 6 feet of a corner) and then at least every 12 feet apart along the wall. Mark your wall layout with a tape measure before you call a rough-in inspection.

Any uninterrupted wall section 2 feet or wider counts as "wall space" and needs the 6-foot rule applied. That includes short walls between doorways, the strip of wall next to a fireplace, and the back of a kitchen peninsula. Fixed room dividers (half-walls, railings, built-in bookshelves) count too. Skip this and you fail rough-in — you will be opening up finished drywall to add a receptacle.

Kitchen counters are tighter: a receptacle every 2 feet of countertop with no stretch over 4 feet without one. Measured along the counter, not the wall. Island and peninsula counters over 24 inches wide and 12 inches deep each need at least one receptacle, and under the 2020 NEC these are usually fed by two 20-amp small-appliance branch circuits. Toaster + coffee maker on the same 15-amp circuit is a tripped breaker waiting to happen.

NEC does not actually mandate a specific height for general receptacles in habitable rooms — "convenient" is the word used. The habit is 12–18 inches to the center of the box. Kitchen countertop receptacles must sit no more than 20 inches above the countertop so a cord does not drape over a hot burner (210.52(C)(5)). Mark your box heights before you nail in — fishing a box 2 inches up or down after drywall is painful.

Hallways 10 feet or longer need at least one receptacle (210.52(H)). Bathrooms need a receptacle within 36 inches of the outside edge of each basin on a dedicated 20A circuit (210.52(D)). Laundry areas need their own dedicated 20A circuit for the washer (210.11(C)(2)). These are the three "gotchas" DIYers skip — all three fail inspection on their own.

Missouri has no statewide electrical code — adoption is city/county. Kansas City requires a permit for most residential electrical work and uses the 2017 NEC for one- and two-family dwellings. St. Louis County adopted the 2023 NEC in January 2025. Springfield and Columbia use the 2020 NEC. Call the building department before you start — the permit fee is $50–150 and the alternative is unpermitted work that your title company flags during a future sale.