The Ontario Building Code | Stairways
(1) Every stairway shall be lighted.
(2) Except as provided in Sentence (3), 3-way wall switches located at the head and foot of every stairway shall be provided to control at least one lighting="http://thehandyforce.com/electrical/" title ="East York Electrician">lighting outlet with fixture for stairways with four or more risers in dwelling units.
Note: On July 1, 2017, Sentence 220.127.116.11.(2) of Division B of the Regulation is amended by striking out "dwelling units" and substituting "a house or an individual dwelling unit". (See: O. Reg. 139/17, s. 130)
(3) The stairway lighting="http://thehandyforce.com/electrical/" title ="East York Electrician">lighting for basements that do not contain finished space or lead to an outside entrance or built-in garage and that serve not more than one dwelling unit is permitted to be controlled by a single switch located at the head of the stairs.