Dedicated circuit?

[Nick Letts]

Under NEC does a wall mounted or baseboard heater have to be on a dedicated circuit??

Its one heater 500w max.

I have a 20 amp Gfci circuit with 3 outlets on it. I wanted to use that and could even eliminate one of the outlets in exchange if necessary.
Also is there code on it being thermostatically controlled?

I really appreciate it.

[Robert Meier]

I don't see anything in Article 424 that require a dedicated circuit for a 500 watt heater. The general rule is that a branch circuit can supply an appliance fastened in place if it doesn't use more than 50% of the circuit's capacity. So with a 20 amp circuit and a 500 watt heater you will be OK. The unit will require a disconnecting means which can be a unit switch with a marked off position that disconnects the ungrounded conductor.

What does the 20 amp circuit currently serve? This heater cannot be added to a kitchen Small Appliance Branch Circuit (SABC). Here are some 2008 code sections:

210.23 Permissible Loads.
In no case shall the load exceed the branch-circuit ampere rating. An individual branch circuit shall be permitted to supply any load for which it is rated. A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified according to its size as specified in 210.23(A) through (D) and as summarized in 210.24 and Table 210.24.
(A) 15- and 20-Ampere Branch Circuits. A 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both, and shall comply with 210.23(A)(1) and (A)(2).
Exception: The small-appliance branch circuits, laundry branch circuits, and bathroom branch circuits required in a dwelling unit(s) by 210.11(C)(1), (C)(2), and (C)(3) shall supply only the receptacle outlets specified in that section.
(1) Cord-and-Plug-Connected Equipment Not Fastened in Place. The rating of any one cord-and-plug-connected utilization equipment not fastened in place shall not exceed 80 percent of the branch-circuit ampere rating.
(2) Utilization Equipment Fastened in Place. The total rating of utilization equipment fastened in place, other than luminaires, shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied.

III. Control and Protection of Fixed Electric Space-Heating Equipment
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, the disconnecting means shall be grouped and marked. The disconnecting means specified in 424.19(A) and (B) shall have an ampere rating not less than 125 percent of the total load of the motors and the heaters. The provision 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.
(C) Unit Switch(es) as Disconnecting Means. A unit switch(es) with a marked “off” position that is part of a fixed heater and disconnects all ungrounded conductors shall be permitted as the disconnecting means required by this article where other means for disconnection are provided in the types of occupancies in 424.19(C)(1) through (C)(4).
(1) Multifamily Dwellings. In multifamily dwellings, the other disconnecting means shall be within the dwelling unit, or on the same floor as the dwelling unit in which the fixed heater is installed, and shall also be permitted to control lamps and appliances.
(2) Two-Family Dwellings. In two-family dwellings, the other disconnecting means shall be permitted either inside or outside of the dwelling unit in which the fixed heater is installed. In this case, an individual switch or circuit breaker for the dwelling unit shall be permitted and shall also be permitted to control lamps and appliances.
(3) One-Family Dwellings. In one-family dwellings, the service disconnecting means shall be permitted to be the other disconnecting means.
(4) Other Occupancies. In other occupancies, the branch-circuit switch or circuit breaker, where readily accessible for servicing of the fixed heater, shall be permitted as the other disconnecting means.

[Jim Port]

Ths poster, I believe, is trying to add this to a laundry circuit. The story seems to change slightly in other forums when the same question is asked.

[Robert Meier]

It cannot be added (legally) to the laundry circuit. Where else is this question posted, over at Holt's?

[Bob Elliott]

I have seen them combined with an A/C circuit which was considered OK since they run at different times.

[Nick Letts]

Originally Posted by Jim Port

Ths poster, I believe, is trying to add this to a laundry circuit. The story seems to change slightly in other forums when the same question is asked.

Just want to clarify what I want to do. In the laundry room I have a dedicated washer circuit and dryer circuit which obviously i cant use. Another circuit which has 3 outlets and is gfci. Thats the one I want to add to if possible.

Can I use that?

Can I get away with a plug in if not.....I believe they have to be hardwired?


I appreciate it

[Robert Meier]

If the unit is factory wired as cord and plug then you can just plug it in to that 20 amp circuit. Adding a cord and plug to a unit that is listed for hard wiring may nullify the listing and then you would have a problem with 110.3

110.3 Examination, Identification, Installation, and Use of Equipment.
(A) Examination. In judging equipment, considerations such as the following shall be evaluated:
(1) Suitability for installation and use in conformity with the provisions of this Code
FPN: Suitability of equipment use may be identified by a description marked on or provided with a product to identify the suitability of the product for a specific purpose, environment, or application. Suitability of equipment may be evidenced by listing or labeling.
(2) Mechanical strength and durability, including, for parts designed to enclose and protect other equipment, the adequacy of the protection thus provided
(3) Wire-bending and connection space
(4) Electrical insulation
(5) Heating effects under normal conditions of use and also under abnormal conditions likely to arise in service
(6) Arcing effects
(7) Classification by type, size, voltage, current capacity, and specific use
( Other factors that contribute to the practical safeguarding of persons using or likely to come in contact with the equipment
(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

[Nick Letts]

Originally Posted by Robert Meier

If the unit is factory wired as cord and plug then you can just plug it in to that 20 amp circuit. Adding a cord and plug to a unit that is listed for hard wiring may nullify the listing and then you would have a problem with 110.3

so a plug in heater, if purchased as so, would satisfy my heat requirements? I think thats what you are saying but I am being super cautious about doing this right.

Thanks