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.

424.20 Thermostatically Controlled Switching Devices. (A) Serving as Both Controllers and Disconnecting

Means. Thermostatically controlled switching devices

and combination thermostats and manually controlled
switches shall be permitted to serve as both controllers
and disconnecting means, provided they meet all of the
following conditions:

(1) Provided with a marked "ofF' position

(2) Directly open all ungrounded conductors when manually placed in the "oflH position

(3) Designed so that the circuit cannot be energized automatically after the device has been manually placed in the "off" position

(4) Located as specified in 424.19

(B) Thermostats That Do Not Directly Interrupt All Ungrounded Conductors. Thermostats that do not directly interrupt all ungrounded conductors and thermostats that operate remote-control circuits shall not be required to meet the requirements of 424.20(A). These devices shall not be permitted as the disconnecting means.

424.21 Switch and Circuit Breaker to Be Indicating.

Switches and circuit breakers used as disconnecting means shall be of the indicating type.

424.22 Overcurrent Protection.

(A) Branch-Circuit Devices. Electric space-heating equipment, other than such motor-operated equipment as required by Articles 430 and 440 to have additional over-current protection, shall be permitted to be protected against overcurrent where supplied by one of the branch circuits in Article 210.

Resistance Elements. Resistance-type heating elements

in electric space-heating equipment shall be protected
at not more than 60 amperes. Equipment rated more than 48 amperes and employing such elements shall have the heating elements subdivided, and each subdivided load shall not exceed 48 amperes. Where a subdivided load is less than 48 amperes, the rating of the supplementary over-current protective device shall comply with 424.3(B). A boiler employing resistance- type immersion heating elements contained in an ASME-rated and stamped vessel shall be permitted to comply with 424.72(A).
(C) Overcurrent Protective Devices. The supplementary overcurrent protective devices for the subdivided loads specified in 424.22(B) shall be (1) factory-installed within or on the heater enclosure or supplied for use with the heater as a separate assembly by the heater manufacturer;(2) accessible, but shall not be required to be readily accessible; and (3) suitable for branch-circuit protection.
FPN: See 240.10.
Where cartridge fuses are used to provide this overcurrent protection, a single disconnecting means shall be permitted to be used for the several subdivided loads.
FPN No. 1: For supplementary overcurrent protection, see 240.10.
FPN No. 2: For disconnecting means for cartridge fuses in circuits of any voltage, see 240.40.

(D) Branch-Circuit Conductors. The conductors supply ing the supplementary overcurrent protective devices shall be considered branch-circuit conductors.

Where the heaters are rated 50 kW