10.4 Appliances and Fixed Electric Space Heating

Article 422 — Appliances

422.10(A) Individual Circuits. The branch-circuit rating for an appliance that is a continuous load, other than a motor-operated appliance, shall not be less than 125 percent of the marked rating, or not less than 100 percent of the marked rating if the branch-circuit device and its assembly are listed for continuous loading at 100 percent of its rating.

Branch circuits and branch-circuit conductors for household cooking appliances shall be permitted to be in accordance with Table 220.55.

The rating of an individual branch circuit supplying a motor-operated appliance not having a marked rating shall be in accordance with Part II of Article 430.

422.10(B) Circuits Supplying Two or More Loads. For branch circuits supplying appliance and other loads, the rating shall be determined in accordance with 210.23.

422.11 Overcurrent Protection. Appliances shall be protected against overcurrent in accordance with 422.11(A) through (G) and 422.10.

• (E) Single Non-Motor-Operated Appliance. If the branch circuit supplies a single non-motor-operated appliance, the rating of overcurrent protection shall (1) not exceed that marked on the appliance; (2) not exceed 20 amperes if the overcurrent protection rating is not marked and the appliance is rated 13.3 amperes or less; or (3) not exceed 150 percent of the appliance rated current if the overcurrent protection rating is not marked and the appliance is rated over 13.3 amperes. Where 150 percent does not correspond to a standard rating, the next higher standard rating shall be permitted.
• (F) Electric Heating Appliances Employing Resistance-Type Heating Elements Rated More Than 48 Amperes. The heating elements shall be subdivided such that each subdivided load does not exceed 48 amperes, and each subdivided load shall be protected at not more than 60 amperes.

422.16 Flexible Cords. Flexible cord shall be permitted for the connection of appliances to facilitate their frequent interchange or to prevent the transmission of noise or vibration, or to facilitate the removal or disconnection of appliances that are fastened in place, where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance or repair and the appliance is intended or identified for flexible cord connection.

422.16(B)(2) Built-In Dishwashers and Trash Compactors. Cord length shall be 3 feet to 4 feet (0.9 m to 1.2 m) measured from the face of the attachment plug to the plane of the rear of the appliance, with the receptacle located to protect against physical damage and accessible.

422.16(B)(4) Range Hoods. Cord length shall be 18 inches to 36 inches (450 mm to 900 mm), the receptacle shall be accessible, and the receptacle shall be supplied by an individual branch circuit.

422.31(A) Rated at Not Over 300 Volt-Amperes or 1/8 Horsepower. For permanently connected appliances rated at not over 300 volt-amperes or 1/8 horsepower, the branch-circuit overcurrent device shall be permitted to serve as the disconnecting means.

422.31(B) Appliances Rated over 300 Volt-Amperes. For permanently connected appliances rated over 300 volt-amperes, the branch-circuit switch or circuit breaker shall be permitted to serve as the disconnecting means where the switch or circuit breaker is within sight from the appliance or is capable of being locked in the open position. The provisions for locking or adding a lock to the disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed.

422.33 Disconnection of Cord-and-Plug-Connected Appliances. For cord-and-plug-connected appliances, an accessible separable connector or an accessible plug and receptacle shall be permitted to serve as the disconnecting means.

422.51 Vending Machines. Cord-and-plug-connected vending machines manufactured or remanufactured on or after January 1, 2005, shall be provided with GFCI protection as an integral part of the attachment plug or located within 12 inches of the attachment plug. Older machines shall be connected to a GFCI-protected outlet.

422.5 Ground-Fault Circuit-Interrupter Protection for Personnel lists the appliances requiring GFCI protection, aligning with 210.8(D): automotive vacuum machines, drinking water coolers and bottle fill stations, high-pressure spray washing machines, tire inflation machines, vending machines, sump pumps, dishwashers, and specified cooking appliances.

Article 424 — Fixed Electric Space-Heating Equipment

424.3(A) Branch Circuits. Branch circuits supplying two or more outlets for fixed electric space-heating equipment shall be rated 15, 20, 25, or 30 amperes. In other than a dwelling unit, fixed infrared heating equipment shall be permitted to be supplied from branch circuits rated not over 50 amperes.

424.3(B) Branch-Circuit Sizing. "The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices supplying fixed electric space-heating equipment consisting of resistance elements with or without a motor shall not be less than 125 percent of the total load of the motors and the heaters. A contactor, thermostat, relay, or similar device, listed for continuous operation at 100 percent of its rating, shall be permitted to supply its full-rated load."

So electric heat is always a continuous load for branch-circuit purposes. A 5000-watt, 240-volt baseboard heater draws 20.8 amperes, and 20.8 x 1.25 = 26 amperes, requiring a 30-ampere circuit with 10 AWG copper conductors.

424.19 Disconnecting Means. Means shall be provided to simultaneously disconnect the heater, motor controller(s), and supplementary overcurrent protective device(s) of all fixed electric space-heating equipment from all ungrounded conductors. Where heating equipment is supplied by more than one source, feeder, or branch circuit, the disconnecting means shall be grouped and marked.

• (A) Heating Equipment with Supplementary Overcurrent Protection. The disconnecting means shall be within sight from the supplementary overcurrent protective devices, on the supply side of these devices, and shall comply with (A)(1) or (A)(2) for the motor controller and heater location.
• (B) Heating Equipment Without Supplementary Overcurrent Protection. The disconnecting means shall comply with (B)(1) for units with motors and (B)(2) for units without motors.
• (C) Unit Switch as Disconnecting Means. A unit switch with a marked-off position that is part of the heater and disconnects all ungrounded conductors shall be permitted as the disconnecting means where other means for disconnection are provided in the specified occupancies.

424.35 Marking of Heating Cables. Each unit shall be marked with the identifying name or identification symbol, catalog number, and ratings in volts and watts or volts and amperes. Each unit length of heating cable shall have a permanent legible marking on each nonheating lead located within 3 inches of the terminal end. The lead wire shall have the following color identification to indicate the circuit voltage on which it is to be used:

424.36 Clearances from Other Objects and Openings. Heating elements of cables shall be separated at least 8 inches (200 mm) from the edge of outlet boxes and junction boxes that are to be used for mounting surface luminaires. A clearance of not less than 2 inches (50 mm) shall be provided from recessed luminaires and their trims, ventilating openings, and other such openings in room surfaces. Sufficient area shall be provided to ensure that no heating cable is covered by any surface-mounted unit.

424.38 Area Restrictions. (A) Heating cables shall not be installed in commercial garages, in closets, over walls or partitions that extend to the ceiling, or over cabinets whose clearance from the ceiling is less than the minimum horizontal dimension of the cabinet. (B) Heating cables shall not extend beyond the room or area in which they originate. (C) Heating cables shall not be installed in damp or wet locations.

424.39 Clearance from Other Objects and Openings and 424.41 Installation of Heating Cables on Dry Board, in Plaster, and on Concrete Ceilings contain the detailed installation rules, including that cables shall not be installed in walls except as permitted, shall be free from contact with any metal, and shall be spaced not less than 2 inches (50 mm) apart except at crossings.

424.44 Installation of Cables in Concrete or Poured Masonry Floors. (A) Watts per unit length shall not exceed 16.4 watts per linear foot of cable. (B) Spacing between adjacent runs shall not be less than 1 inch (25 mm) on centers. (E) Cables shall be secured in place by nonmetallic frames or spreaders or other approved means while the concrete or other finish is applied. (F) Cables shall not be installed where they bridge expansion joints unless protected from expansion and contraction. (G) Ground-Fault Circuit-Interrupter Protection for Personnel. GFCI protection for personnel shall be provided for cables installed in electrically heated floors of bathrooms, kitchens, and in hydromassage bathtub locations.

Baseboard Heaters and Receptacle Outlets

210.52 Informational Note and long-standing manufacturer instructions address a practical conflict: listed baseboard heaters typically state that receptacle outlets shall not be located above the heater, because a cord draped into the heater is a fire hazard. Where the heater's instructions say this, 110.3(B) makes it enforceable.

The Code side is that 210.52(A) requires receptacles at the 6-foot spacing along wall space, and permanently installed electric baseboard heaters with factory-installed receptacle outlets, or outlets provided as a separate listed assembly, shall be permitted in lieu of a receptacle outlet required by 210.52. However, such receptacle outlets shall not be connected to the heater circuits.

In Alaska, where baseboard heat frequently occupies most of the exterior wall length, this rule combination drives real layout decisions: use listed heater-mounted receptacle assemblies fed from a separate general-purpose circuit, or plan the heater and receptacle layout together so the 6-foot rule is satisfied without placing an outlet above a heater.