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Class II AC Surge Protective Device MD1

MOREDAY MD1 ac surge protector 275v 385v 420v,type 2 surge protective devices ac spd.

  • Features (plug-in, remote signaling, compact, narrow design for little space)
  • According to IEC 61643-31
  • Thermal disconnect inside for fault indication
  • AC configuration (single/3-phase)
  • RoHS material

Stable Delvery Time

Technical Support

2 Years

MOREDAY MD1 AC Surge Protective Device

MOREDAY MD1 AC Surge Protective Device : Elevate Your Power Protection

The MD1-40 AC Surge Protective Device from Moreday offers robust safety and reliability for your electrical systems, primarily designed to shield commercial and industrial environments from sudden voltage surges and spikes. This device is ideal for systems up to 380V in AC power supply systems like TN-S, TN-C-S, TT, and IT, ensuring your operations run uninterrupted.

Technical Excellence and Innovations

Rated Operating Voltage (Un): 275V – 385V, adaptable for versatile industrial needs.
Maximum Continuous Operating Voltage (Uc): Up to 420V for continuous protection.
Nominal and Maximum Discharge Current: 20kA to 100kA, handling severe surge conditions with ease.
Voltage Protection Level (Up): Exceptionally low residual voltage levels (≤2.8 kV) during surge events.
Rapid Response Time: Less than 25 nanoseconds, ensuring immediate protection against voltage transients.
Ease of Maintenance: Features a modular design with plug-in protection modules, color-coded status indication (green for normal, red for fault), and easy replacement without system downtime.

Key Features

AC Surge Protective Device
Installation Flexibility

Designed for mounting on 35mm standard DIN rails, facilitating straightforward installation in diverse settings.

Environmental Resilience

Operates effectively within a temperature range of -40°C to +85°C, suitable for harsh industrial environments.

Material Integrity

Constructed with burning-proof Nylon, ensuring durability and safety under extreme conditions.


Data Centers

Manufacturing Facilities

Renewable Energy Installations

Why Choose Moreday?

Global Certifications

Complying with international standards such as IEC61643-1 and GB18802.1, with robust quality checks.

Proven Track Record

Over 15 years of innovation with a footprint in over 100 countries and a production capacity exceeding 5GW.

Customer-Centric Innovations

Tailor-made solutions addressing specific needs backed by a professional life cycle management system.

Choosing MOREDAY’s MD1 AC Surge Protective Device means selecting a solution that not only meets but exceeds the protective needs of your sophisticated electrical systems. Let’s safeguard your equipment with precision-engineered protection that stands the test of time. Elevate your power protection strategy with MOREDAY—where safety and quality converge.




Technical Parameters

380V/220V 0.36

Rated Operating Voltage Un(V~)


Maximum Continuous Operating Voltage Uc(V~)


Voltage protection Level Up(V~)kV


Nominal Discharge Current In (8/20s)kA


Response Time (ns)


Test Standard

IEC61643.1, GB1 8802.1

Operating Environment(centigrade)

-40℃ ~+85℃

Max Connection Line

35mm² hard wire/35mm² strand wire copper line

Recommended Connection L ine

16mm² hard wire/25mm² strand wire copper line


Standard Rail 35mm

Material of Outer Covering

Burning-proof Nylon

popular questions


1. What types of power supply systems is the MD1-40 AC SPD compatible with?

The MD1-40 AC SPD is designed for AC 50/60Hz power supply systems and is compatible with TN-S, TN-C-S, TT, and IT systems. This versatility makes it suitable for a wide range of industrial and commercial installations.

2. How does the MD1-40 AC SPD indicate its operational status?

The MD1-40 features an easy-to-understand color-coded indicator: green signifies normal operation, while red indicates a fault condition. This helps in quick diagnostics and maintenance.

3. Can the MD1-40 AC SPD be installed outdoors?

The MD1-40 is designed with an IP20 rating, which is suitable for indoor installations. For outdoor applications, additional protective enclosures may be required to shield it from environmental factors.

4. What is the response time of the MD1-40 AC SPD, and why is it important?

The response time of the MD1-40 AC SPD is less than 25 nanoseconds, which is crucial for protecting sensitive electrical equipment from rapid voltage spikes. This quick response helps in preventing potential damage to connected devices.

5. How often does the MD1-40 AC SPD need maintenance or replacement?

The lifespan of the MD1-40 depends on the frequency and severity of the voltage surges it encounters. The device is designed with a modular architecture, allowing for easy replacement of the protection module without needing to replace the entire unit. Regular checks are recommended to ensure optimal performance.

6. Can the MD1-40 AC SPD handle lightning-induced surges?

Yes, the MD1-40 is capable of handling surges induced by lightning, thanks to its high nominal discharge current (In) of up to 40kA and maximum discharge current (Imax) of up to 100kA. It provides robust protection against significant surge events.

7. What should I do if the indicator shows red?

If the red indicator light is on, it suggests a fault condition in the surge protection module. It is advisable to check the module for any damage and replace it if necessary. This ensures continuous protection and minimizes downtime in your operations.

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