The SLZC series zone sensing controls is designed to be either integral inside the battery unit or external outside the battery unit and to automatically trigger emergency lighting operation in conjunction with local/zone normal lighting circuit failure. The SLZC panel is installed with zone monitoring circuits connected to regular, localized lighting circuits. Should one of these circuits loose power, the SLZC panel will cause the emergency lighting unit to supply power to the luminaires it supports. The localized area where the power failed is now illuminated by emergency lighting. Without the SLZC panel, this area would be exposed to the potential dangers of total darkness.