Emergency lighting for the first application is emergency lighting in non-fire situations. Because there was no fire in the environment at this time, the power supply of the normal lighting suddenly stopped the lighting. At this time, the environment suddenly darkens, and for some ongoing operations can not be stopped suddenly, so it is necessary to temporarily do some treatment, for places where people are more concentrated, darkness makes people feel fear, then people need to evacuate as soon as possible, for this reason these places should restore a certain brightness as soon as possible, obvious evacuation instructions are required, and normal lighting lighting because of the failure to lose power supply and can not continue to provide lighting for these places, which requires another set of lighting, The power supply for this set of lighting must be independent of the additional power supply of the normal lighting power supply.
Emergency lighting for the second application is emergency lighting in a fire situation. Even if a fire occurs in the environment at this time, the power supply of daily lighting is still in normal power supply, daily lighting is present, but the existence of normal lighting must be conducive to fire fighting and evacuation, will bring negative impact, at this time it is necessary to cut off the fire equipment electricity for other power supply lines, including the power supply line of normal lighting. After the normal lighting is cut off, in order to fire fighting operations and personnel evacuation, it is necessary to set up another set of lighting, and this set of lighting belongs to the fire load electricity, and its power supply is independent of the normal lighting power supply.
