The DEHNguard DG M TT 275 FM is a high-performance Type 2 Surge Protective Device (SPD) engineered specifically for TT earthing systems. Manufactured by DEHN (Germany), this modular surge arrester provides reliable protection against transient overvoltages caused by indirect lightning strikes, grid switching operations, and voltage spikes.

Designed for installation inside the main distribution board on a DIN rail, the DG M TT 275 FM protects downstream electrical equipment by safely diverting surge energy to earth (PE) while limiting residual voltage to a safe level (Up 1.5 kV).

The FM version includes an integrated remote signaling contact, enabling external fault monitoring via alarm or control systems — ideal for professional and industrial installations.

🛠 Condition

Tested and fully functional

🕒 Warranty

12-month warranty provided by Green Energy

⚙️ Technical Specifications

• Model: DG M TT 275 FM

• Article Number: 952 050

• SPD Classification: Type 2 (T2)

• System Configuration: TT (N/PE protection)

• Maximum Continuous Operating Voltage (Uc): 255 V AC (50/60 Hz)

• Nominal Discharge Current (In): 20 kA

• Maximum Discharge Current (Imax): 40 kA

• Voltage Protection Level (Up): 1.5 kV

• Mounting: DIN rail, modular (3-module width)

• Status Indicator: Green = OK / Red = Replace cartridge

• Remote Signaling: Yes (FM contact)

• Certification: CE

• Country of Manufacture: Germany

🔧 Key Features

✔ Type 2 surge protection for TT systems
✔ High discharge capacity up to 40 kA
✔ Modular design with replaceable cartridges
✔ Integrated visual status indicator
✔ Remote alarm signaling contact (FM version)
✔ DIN rail mounting for fast installation
✔ Premium German engineering by DEHN

🛠 Applications

• Residential electrical distribution boards

• Industrial and commercial installations

• AC side protection of photovoltaic systems (TT systems)

• Protection of inverters, PLCs, and automation panels

• Safeguarding sensitive electronic equipment

⚡ Operating Principle

In the event of a transient overvoltage:

• Surge energy is diverted safely to earth (PE)

• Residual voltage is limited to Up = 1.5 kV

• Downstream equipment remains protected

If the protection module reaches end-of-life, the visual indicator switches from green to red, signaling cartridge replacement.

📦 Scope of Delivery

• 1× DEHNguard DG M TT 275 FM surge protective device (as shown)

🚀 Professional-grade surge protection for TT electrical systems — engineered in Germany and tested for reliable performance by Green Energy.