Switches + Receptacles Types Reference

Why this matters

Wrong device for application = code violation OR safety hazard. Customer with a 15A outlet on a 20A circuit, no GFCI in the bathroom, OR a single-pole switch where 3-way needed - gets it wrong, calls back, loses trust. The right device every time = solid work. This is the field card.

Switch types

Single-pole: one switch controls one light. Most common. Two screw terminals (one black, one brass). No on/off marking required.

Three-way: two switches control one light (top + bottom of stairs). 3 screws (1 common dark, 2 travelers brass). NO on/off marking.

Four-way: middle switch in 3-or-more-location control. Between two 3-way switches. 4 screws.

Double-pole: 240V circuit; 2 hot wires switched simultaneously. 4 screw terminals.

Dimmer: switches AND varies brightness. Incandescent + LED-compatible dimmers differ.

Motion sensor: PIR sensor + switch; lights on with motion.

Smart switch (Wi-Fi, Z-Wave, Zigbee): home automation; some need neutral, some don't.

Pilot light switch: indicator lamp shows when switched on (basement, exterior).

Timer switch: digital countdown OR programmable; bath fan + outdoor lights.

Receptacle types

15A standard duplex (NEMA 5-15R): most common residential outlet. 120V, 15A.

20A duplex (NEMA 5-20R): one slot perpendicular (T-shaped). Required on dedicated 20A circuit.

240V outlets:

• 30A dryer (NEMA 14-30R): four-prong
• 50A range (NEMA 14-50R): four-prong, used for ranges + EV chargers
• 30A older dryer (NEMA 10-30R): three-prong; no separate ground (legacy)
• 50A older range (NEMA 10-50R): three-prong; legacy

GFCI (Ground-Fault Circuit Interrupter): trips on imbalance to earth. Required: kitchen counter, bath, garage, outdoor, basement, laundry. NEC 210.8.

AFCI (Arc-Fault Circuit Interrupter): trips on series + parallel arc faults. Required: most habitable rooms. NEC 210.12.

Dual-function (CAFCI + GFCI): combination protection.

USB-integrated receptacle: built-in USB ports. Limited charging speed (typically 2.1A per port).

Tamper-resistant (TR): child-safety shutters; REQUIRED on all new residential receptacles per NEC 406.12.

Weather-resistant (WR): outdoor-rated for damp/wet locations.

In-use weatherproof cover: required outdoor with continuously-plugged cord.

Receptacle ratings

Switch wiring basics

Single-pole: line in (black) to one terminal, load out (black) to other. Neutral straight through (white passes; not switched). Ground to green screw.

3-way (with 14/3 cable): dark screw = common (line OR load); 2 brass screws = travelers. Red + black wires of 14/3 are travelers; white usually neutral except in switch-loop scenarios.

Switch loop (older wiring): only 14/2 (no neutral); requires re-marking. New code requires neutral at switch box.

GFCI installation

At outlet (typical kitchen): wired LINE in (incoming power) + LOAD out (downstream outlets). Downstream outlets all GFCI-protected.

At breaker: whole circuit GFCI-protected from panel.

Self-test feature (post-2015): GFCI tests itself every few seconds; lights status LED.

AFCI installation

At breaker (most common): AFCI breaker replaces standard.

Combination AFCI/GFCI breaker covers both.

Common AFCI nuisance trips: motor brushes (vacuum, hair dryer); cheap LED drivers; cordless tool chargers. Resolve by replacing the noisy device OR upgrade to a less-sensitive AFCI breaker.

Locations where GFCI required (residential)

• All kitchen counter outlets
• Bath outlets
• Garage outlets
• Outdoor outlets
• Pool / spa area
• Basement (unfinished + finished both)
• Crawl space
• Laundry
• Wet bar
• Boathouse / dock
• Within 6 ft of any sink

Locations where AFCI required (residential)

• Most habitable rooms (bedroom, living, dining, family, hallway)
• Recreation room, library, sunroom
• Closets, dens

Common device mistakes

15A on 20A circuit (single device limit OK; multiple receptacles must be 20A on 20A circuit per NEC 210.21). Missing tamper-resistant (TR) on new install. No GFCI in required location. AFCI omitted from required circuit. Pigtail neutral wire to old GFCI line side (wires backstabbed; failed). Wire-nut splice in shallow box (overfill). Decora device in narrow plate (won't fit). Smart switch without neutral wire (won't function).

Spec-grade vs commercial-grade

For pro service work: spec-grade minimum; commercial for high-use locations.

Color coding

White: standard interior, neutral.

Almond: matches older trim.

Ivory: matches older trim variant.

Black: commercial / industrial.

Gray: commercial / utility.

Dimmer compatibility

Incandescent: any dimmer works.

Halogen: dimmable.

LED: requires LED-rated dimmer; some bulbs don't dim smoothly.

CFL: most don't dim; some "dimmable" CFL work poorly.

Fluorescent tube: needs special dimmer + dimmable ballast.

Smart bulbs (Hue, LIFX): do NOT use dimmer; smart-bulb has own dimming.

Receptacle install workflow

1. Confirm power off + verify dead with multimeter
2. Remove old device + photo wiring
3. Strip new wire (typical 1/2" - 5/8" exposed)
4. Side-screw termination (don't backstab); torque 16 in-lb residential
5. Pigtail multiple wires + use wire nut + 6" pigtail to device
6. Push device into box without binding wire
7. Mount + plate
8. Power on + test (voltage tester at all 3 outlets if duplex)

Code compliance check

• TR on all residential receptacles (NEC 406.12)
• GFCI in required locations (NEC 210.8)
• AFCI on required circuits (NEC 210.12)
• 18-inch rule (kitchen-counter receptacle spacing)
• 6-foot rule (within 6 ft from any point on a wall)

References

• NEC Article 210 (Branch Circuits)
• NEC 406 (Receptacles + Cord Connectors)
• NEC 404 (Switches)
• UL 498 (Attachment Plugs + Receptacles)
• UL 943 (Ground-Fault Circuit Interrupters)
• Manuall internal: Wire Termination Types, Breaker + Panel Reference