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Twilight switch: easy ignition diagram

    photocell lighting

    Connection of a single twilight switch

    The twilight switch allows the control of electrical devices, usually lighting, based on ambient light conditions. The brightness threshold is adjustable.

    They are typically modular types (mounted on DIN rails for electrical panels), but also exist in micro-module enclosures to be wired in confined spaces such as junction boxes or drywall enclosures.

    Connection with contactor

    The power contactor enables the supply of one or multiple electrical devices with a significant overall power. The breaking capacity (expressed in amperes) of the contactor will consequently be determined based on the devices being powered.
    A setup with a contactor also allows the supply of control (twilight switch) and power (lamps) with different voltages (not shown in the diagram).

    Twilight switch: diagram

    Connection with contactor and timer

    The programmable timer will allow the activation of devices only during specified days and times, for example, from Monday to Friday between 7:30 AM and 7:00 PM. Of course, these devices will only be powered during these time slots if the preset brightness threshold is crossed.

    Twilight switch: diagram

    Twilight switch for junction boxes and equipment enclosures

    These are no longer modular switches (placed on rails in a panel). These are designed to be arranged in junction boxes or recessed equipment enclosures.

    It will be challenging to associate them with timers and contactors. Although also available in micro-module format for enclosures, these additional modules added to the switch will no longer be “micro,” so they will often be reserved for simple applications.

    For these reasons, on the following diagrams, we will simply connect the twilight switches directly to the serviced lamps.

    As these types of switches are once again intended for generally simpler applications, it is common to have only one power feed relay to control lamps or other electrical devices. The internal contact in the device is already connected to the phase serving as the power supply.

    Twilight switch: diagram

    Same diagram, but this time with a dry contact for powering the devices.

    Source: entraidelec.com | CC

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