Is a 3 way switch required at the stairs to a basement with no other entryway? We were given a violation for not having a 3 way switch in a basement with no entryway.
Stairway Lighting is Required, with light switches at top and bottom of the stairway if the stairs encompass more than three stair treads (Canada) or six stair treads (U.S.).
I do not know the codes but I would guess that if you are in the basement during the day and you stay there until night time, then they want you to be able to turn on the lights for the stairs as a safety concern.
Nowhere is it written that the lights must be switched at all. You can have a 24x7 light or a day/night light if there is natural light.
Also, the lights can be on a motion sensor, but the sensors must be arranged competently to see approaching stair users, which is harder than you think.
Do what common sense would engage yourself to do.
Codes are written with safety in mind, but there are not capable of covering every single situation.
If it were my place, and there was the slightest chance where a extra light switch could prevent an injury, I would make certain there was another switch.
Falling down multiple stairs can be hazardous to your health. Especially in the DARK.