Manuale Timer Legrand 03740 _hot_ May 2026

Legrand 03740 Manuale Timer: Precision Control for Daily Electrical Circuits

The Legrand 03740, often referred to as the Manuale Timer, is a high-quality, electromechanical time switch designed for reliable, repeatable control of lighting, ventilation, heating, or other electrical loads. Built for both residential and light commercial applications, this timer offers a simple, robust solution for automating daily schedules without the need for digital programming or network connectivity.

Core Functionality: 24-Hour Programmable Switching

At its heart, the Legrand 03740 operates on a 24-hour cycle. Using a user-friendly, dial-based interface, it allows you to program up to 48 switching operations per day (on/off) with a minimum interval of 15 minutes. This is achieved by lifting or lowering plastic tappets (actuators) around the edge of the time dial—each tappet representing a 15-minute segment.

Key Technical Specifications:

• Supply Voltage: 230V AC, 50/60Hz
• Switching Capacity: 16A resistive (e.g., heating) / 10A inductive (e.g., motors, lighting ballasts)
• Programmable Actions: Up to 48 (ON/OFF) per day
• Shortest Switching Interval: 15 minutes
• Reserve (Power backup): 150 hours (approx. 6 days) – maintains time and program during power outages
• Contact Type: Single-pole, single-throw (SPST) – potential-free changeover contact
• Dial Graduation: 96 tappets (15 min each)

Installation & Mounting:

• Form Factor: DIN rail mount (standard EN 60715)
• Width: 1 modular unit (17.5 mm)
• Terminals: Screw-type terminals for solid or stranded wire
• Protection Class: IP20 (for installation in distribution board)

How to Use the Manuale Timer (Quick Guide):

1. Set Current Time: Rotate the outer dial clockwise (only!) until the pointer aligns with the correct time of day. Note that the inner dial follows a 24-hour scale.
2. Set Programs:
   • To turn a device ON during a period: Push the external tappets outward (away from center) for all 15-minute segments during the desired ON window.
   • To turn a device OFF during a period: Leave tappets in their default inward position.
3. Select Mode: Use the manual selector switch (typically located on the side or top of the unit) – positions: I = permanent ON, 0 = permanent OFF, Timer = automatic program running.
4. Power Reserve: No battery is required. When power is applied, the internal rechargeable NiMH battery (or supercapacitor) charges automatically; it keeps the clock running for approx. 6 days without mains power.

Best Applications:

• Lighting control: Shop window displays, outdoor garden lights, corridor lighting.
• Ventilation: Bathroom fans, attic ventilation on a schedule.
• Small heating systems: Floor heating in bathrooms, towel radiators.
• Signage & advertising displays.

Advantages over digital timers:

• No complex menus – immediate visual feedback of the program.
• 100% reliable after power loss – the mechanical dial position doesn’t change, and the reserve keeps time.
• Durable, long life – tested for over 100,000 switching cycles.

Important Notes:

• Do not exceed the rated switching capacity (16A resistive). For higher loads, use an external contactor.
• The timer is not battery-free but contains a rechargeable reserve; initial charging may take up to 100 hours—leave connected to mains before first programming.
• The 03740 is a single-channel, 24-hour timer. For weekly or 2-channel applications, see other Legrand models (e.g., 03750 or 412000).

Conclusion

For professionals and homeowners seeking a no-nonsense, tactile, and durable time switch, the Legrand 03740 Manuale Timer is an industry-standard choice. Its robust mechanical design, combined with a generous power reserve and straightforward operation, ensures that your electrical circuits operate exactly when you need them—day after day.

Legrand – Built for life, engineered for simplicity.

Case 3: Using as a 24/7 Cyclic Timer (e.g., for aquariums)

• Program 1ON at 00:00 (midnight) and 1OFF at 00:10 (ten minutes past midnight).
• Program 2ON at 06:00 and 2OFF at 06:10.
• Result: Load runs 10 minutes every 6 hours.

6. Domande Frequenti (FAQ)

D: Posso programmare intervalli inferiori a 15 minuti? R: No. Il Legrand 03740 ha una risoluzione di 15 minuti. Per intervalli più brevi (es. 1 minuto) occorre un timer digitale (es. Legrand 03747). Manuale Timer Legrand 03740

D: Perché il mio timer ha i numeri romani (I, II, III) invece che 1,2,3? R: È una variante estetica. I = 1 ora, XII = 12 ore, ripetuti due volte per il ciclo di 24 ore.

D: Il manuale originale dov’è? R: Legrand non produce più manuali cartacei. Puoi scaricarlo dal sito Legrand Italia → Supporto → Cerca "03740". In alternativa, le istruzioni qui descritte sono le medesime.

D: Posso usare questo timer per una caldaia o un motore? R: Sì, ma verifica la corrente assorbita. Per carichi induttivi (motori, elettrovalvole), la portata massima consigliata è 10 A. Per caldaie va benissimo.

Chapter 4: Manual Override and Special Modes

The Manuale Timer Legrand 03740 includes an intuitive manual override system, essential for holidays or unexpected needs.

2. Wiring Diagram (Crucial Step)

The device usually has 4 terminals (2 input, 2 output). The terminals are often labeled 1, 2, 3, 4 or L/N Input & L/N Output.

Standard Wiring Configuration:

1. Terminals 1 & 2 (Input): Connect the Power Supply.

   • Terminal 1: Phase (L)
   • Terminal 2: Neutral (N)
   • (Check device markings, usually terminals 1-2 are for the power supply coil).

2. Terminals 3 & 4 (Output): Connect the Load (Appliance).

   • Terminal 3: Phase Out to Load
   • Terminal 4: Neutral Out to Load

Note: The Legrand 03740 is an Omnipolar device, meaning it breaks both Phase and Neutral simultaneously for safety. Ensure the power is off before installation.

Key Specifications

• Supply Voltage: 230V AC ~ 50/60Hz
• Switching Capacity: 16A (resistive load) / 10A (inductive load)
• Power reserve (battery backup): 150 hours (approx. 6 days) – retains programming during power outages.
• Number of programs: Up to 10 ON/OFF commands per day (total 70 per week).
• Minimum switching interval: 1 minute.
• Display: LCD with backlight (varies by revision). Some models have a blue backlight; older ones are non-backlit.
• Physical form factor: 2 modular units (35mm per module).

2. Technical Specifications

Before programming, the user must verify the electrical parameters to ensure compatibility with the load.

• Model Number: 03740 (often part of the Plexo or Ecogreen range).
• Rated Voltage: 230 V AC (50/60 Hz).
• Contact Configuration: 1 Changeover (1 CO / SPDT).
• Rated Current: Typically 16 A (Resistive load), 10 A (Inductive load).
• Min. Switching Interval: 1 minute.
• Memory Capacity: Up to 50 to 56 switching operations (model dependent).
• Backup Battery: Integrated rechargeable lithium battery (non-replaceable in some older units; designed for 100+ hours backup).
• Mounting: DIN Rail (standard 35mm).

5. Operational Scenarios

Scenario A: Office Lighting (Mon-Fri, 08:00 - 18:00)

1. Program 1 ON: Select "MO-FR", Set 08:00.
2. Program 1 OFF: Select "MO-FR", Set 18:00.
3. Leave Programs 2–50 empty.

Scenario B: Bathroom Heater (Twice Daily) Legrand 03740 Manuale Timer: Precision Control for Daily

1. Program 1 ON: 07:00.
2. Program 1 OFF: 08:00.
3. Program 2 ON: 18:00.
4. Program 2 OFF: 20:00.

What is the Legrand 03740?

The Legrand 03740 is a modular digital timer designed for DIN rail mounting inside an electrical panel. It is part of Legrand’s BTicino and Living Now series (depending on the market). This timer is widely used to control lighting, heating, ventilation, irrigation pumps, or any electrical load requiring scheduled ON/OFF cycles.