Earth Bondhon
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Md Jony Islam Author
Md Jony Islam
CalculatorToolsProjectExpert
Reviewers
Małgorzata Koperska, MD Steven Wooding
Last updated: August 9, 2025

Day-Night Sensor Light Wiring Guide & Diagram

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Components List

Single phase Light

Single Phase LED Light

Energy-efficient LED light for single-phase supply

Single phase Light

Well Light Holder

Recessed light holder typically used in ceilings/walls

10A SP MCB

10A SP MCB

Single Pole Miniature Circuit Breaker, 10 Amp

Day-Night Sensor

Day-Night Sensor

Light-sensitive switch that turns circuits on/off based on ambient light

[day-night-sensor]

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Day Night Sensor In Light Wiring

Wire a dusk-to-dawn (day-night) sensor to automatically control lights at sunset and sunrise. Includes wiring steps, safety tips, and common sensor types.

electrical wiring single phase

To install a day-night sensor to wire to automatic lighting, you connect the live wire on your mains to the sensor input, the sensor output to the live terminal on your light, and then all neutrals together. Connections on the ground ought to be firmly fixed. Install the sensor in a place where it gets natural light, but not the direct glare of the controlled source of light, to avoid false switching. This installation will mean your light will be on in the evenings when it becomes dark and off in the mornings when there is light, maximizing convenience as well as consumption of power.

Formula & Table Summary:

Light ON = (Ambient Light < Threshold Lux) → Sensor Output = Live to Load

Light OFF = (Ambient Light ≥ Threshold Lux) → Sensor Output = Open Circuit


Summary Table:

ConditionSensor OutputLight Status
Daylight ≥ ThresholdOpenOFF
Nighttime < ThresholdLive ConnectedON

home electrical wiring single phase

A day-night sensor, also known as a dusk-to-dawn sensor, keeps the lights automatically regulated on the basis of how bright it is. The sensor, once daylight disappears, activates the light, and in the event that the sun emerges, it turns off the light. This is energy-saving, more secure, and eliminates manual operation. The usual way of attaching the wires is to attach the sensor in series with the live supply side of the switch to the light fitting, again taking care to ground well and have the correct polarity. The vast majority of the sensors will need the presence of a neutral connection, though simpler sensor usage has the wires. You must also keep it well-positioned to avoid false triggering- place the sensor in an area where it has a clear view of the sky yet uninterrupted by direct artificial light. The arrangement is appropriate for both LED, CFL, and incandescent lights, provided the compatibility of the specifications of sensor. Never go against the wiring instructions that the manufacturer provides, and ensure observance of electrical safety standards. In case of doubt, employ the services of a licensed electrician to be safe regarding local regulations.

single phase wiring diagram

Lux LevelSensor OutputLight State
800 LuxOpenOFF
300 LuxLive to LoadON
100 LuxLive to LoadON

Frequently Asked Questions - Day Night Sensor In Light Wiring:

What is a day-night sensor?

A sensor (photocell or LDR) that detects ambient light and switches lights on at dusk and off at dawn.

Where do you install the sensor?

Outside or in a location with clear sky exposure, away from direct lamp light to avoid false triggering.

How do I wire a dusk-to-dawn sensor to a light?

Connect mains Live to sensor input, sensor output to fixture Live, and join neutrals; ensure proper earth/grounding.

Do I need a neutral at the sensor?

Some sensors are two-wire (no neutral) but many modern sensors require neutral — check the model spec.

Can I use it with LED lights?

Yes, but choose a sensor and driver compatible with low current/LED inrush characteristics.

Is polarity important when wiring?

Yes — connect Live, Neutral and Earth correctly and follow the sensor’s labeled terminals.

Do sensors need surge protection?

Recommended for outdoor installations to protect against lightning or switching transients.

Can I dim lights with a day-night sensor?

Typical photocells are on/off devices; for dimming you need a sensor + dimmable driver and compatible control circuitry.

How do I prevent false triggers?

Mount sensor away from stray light, reflective surfaces, and position to face the open sky.

Is professional installation required?

If you are not confident working with mains electricity, hire a licensed electrician for safety and code compliance.

Md Jony Islam

Md Jony Islam

CalculatorToolsProject

Founder of Earthbondhon.com

a free online tools website designed to make everyday and engineering-related calculations easier for students, professionals, and hobbyists. The site offers a wide range of basic calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators.