I refer here not primarily to the design and construction of individual products, but to the system design in large modern buildings with automated lighting controls.
I am aware of several cases in which an automatic control system has "accidentally" turned out every light in a large area, leaving the occupants in darkness. This sort of failure does not seem to be addressed by current practice.
In general, it seems to me that most emergency lighting systems light the emergency lights on failure of the mains electricity supply, but do not operate if the mains supply be present, but a defective or misapplied control system turns the lights out during hours of occupation.
It seems to me that the regulations need updating to include something like
"The emergency lights shall operate in case of failure of the electricity supply, AND SHALL ALSO ENSURE THAT THE MINIMUM LIGHTING LEVELS ARE PROVIDED IN THE EVENT OF FAULT, FAILURE, OR MIS-APPLICATION OF ANY AUTOMATIC OR REMOTE CONTROL OF THE LIGHTING SYSTEM" (There is no need to protect against mal-operation of local and manually operated conventional light switches that DIRECTLY CONTROL the ordinary lighting)
