Dusk Switch ETI SOU-1 230V Photocell Relay 230V 16A 1 Contact 50000 lx

The ETI SOU-1 dusk switch is a photocell relay designed for automatic lighting control based on ambient light levels. Intended for 230 V mains systems, this device operates a single changeover contact to switch lighting, signage or control circuits when daylight falls below or rises above a set threshold. The SOU-1 responds to light intensity up to 50,000 lux and is suitable for applications that require dusk-to-dawn or twilight switching without manual intervention.

Advantages

The photocell relay provides reliable automatic operation for lighting control at a 230 V supply and can switch loads up to 16 A on one contact. Its sensitivity to high ambient illumination (up to 50,000 lux) makes it suitable for a wide range of daylight conditions. The device is compact and can be integrated into existing circuits for outdoor and indoor installations where automatic switching based on natural light is needed.

Suitable for

• Automatic street, garden or pathway lighting control
• External signage and display lighting
• Perimeter and security lighting circuits
• Simple control circuits requiring dusk/dawn switching

When it may not be suitable

This dusk switch is intended for standard 230 V AC supplies and single-contact load switching up to 16 A. It is not appropriate for direct switching of heavy three-phase loads, variable-frequency drives, or equipment that requires more than a single contact or higher switching currents. Environments that demand sealed, waterproof enclosures or explosion-proof certification may require a differently specified unit.

Key specifications

• Supply voltage: 230 V AC
• Switching capacity: up to 16 A on one contact
• Contact configuration: single changeover contact
• Light sensitivity: up to 50,000 lux
• Application: dusk/dawn (photocell) switching for lighting and control circuits

How to use

Install the ETI SOU-1 in a location with an unobstructed view of the ambient light to ensure accurate switching. Mount and wire the unit according to local electrical regulations and the device wiring diagram: connect the 230 V supply to the designated input terminals and the controlled circuit to the switched contact. After powering, the relay will operate automatically, closing or opening the contact as ambient light falls below or rises above the sensitivity threshold. Verify correct operation at dusk and dawn and adjust placement if shadows or artificial light sources affect performance.

What to consider before purchase

• Confirm compatibility with the mains supply voltage (230 V AC).
• Check that the load current does not exceed 16 A on the switched contact.
• Ensure the mounting location provides representative ambient light without interference from artificial sources.
• Consider environmental protection requirements (e.g., IP rating) for outdoor installations.

Usage recommendations

For reliable dusk/dawn operation, mount the photocell where it sees natural daylight, away from direct artificial illumination such as nearby lamps or illuminated signs. Test switching behavior at different light levels and, if necessary, adjust placement to avoid false triggering. When controlling inductive loads like motors or transformers, include appropriate protective measures such as RC snubbers or contactors sized for inrush currents.