I have seen several different definitions of bi-level switching, for example in California and New York rules. What is the definition?
Some state regulations define bi-level switching in a particular way for their own jurisdictions. These are specific applications of a more general approach. Bilevel switching is defined as manual or automatic control (or a combination thereof) that provides two levels of lighting power in a space (not including off). A space is defined as an area enclosed by four or more floor to ceiling walls. Dimming or switching would satisfy this definition. Of course, besides satisfying the tax deduction requirements, an installation would also have to satisfy whatever the regulations are for the jurisdiction, which may, but typically don't, require bi-level switching.
