Original MTL7767+ 2-Channel Intrinsically Safe Relay Output Barrier with 15V Safety Description and IIC Gas Group Certification

The MTL7767+ is a high-performance 2-channel shunt-diode safety barrier (Zener barrier) from Eaton's Crouse-Hinds series MTL7700 range, specifically engineered for positive DC systems up to 12V DC requiring intrinsic safety protection in hazardous areas.

This passive device limits the voltage and current that can reach a hazardous area under fault conditions, preventing ignition of flammable atmospheres. With a safety description of 15V, 100 Ω, 150mA, the MTL7767+ is the ideal solution for protecting low-level DC circuits in Zone 0, 1, and 2 hazardous locations (gas groups IIC, IIB, IIA).

The device features a compact 12 mm width and standard DIN rail mounting for easy integration into existing control cabinets. The "+" suffix indicates positive polarity configuration.

The "+" suffix indicates positive polarity, distinguishing it from negative polarity versions and AC versions.

• 2-Channel Efficiency: Two independent intrinsically safe channels in a single compact housing — protects two field devices while using minimal panel space
• Low Voltage DC Optimization: Specifically designed for positive DC systems up to 12V DC — ideal for low-level logic circuits and digital inputs
• 15V Safety Description: Provides safe voltage limiting for low-voltage DC circuits, preventing ignition under fault conditions
• 100 Ω End-to-End Resistance: Low resistance design minimizes voltage drop in sensitive low-voltage circuits
• 150mA Maximum Current: High current capability suitable for switching applications and low-power loads
• IIC Gas Group Certification: Certified for use in the most hazardous gas groups including IIC (hydrogen, acetylene)
• Removable Terminals: Unique removable terminal blocks for easy cabling, maintenance, and loop disconnect by simply unplugging terminals from the side of the module
• Bussed Power Capability: Reduces cabling requirements with integrated bussed power distribution — a unique feature of the MTL7700 series
• Angled Wire Entry: Wire entry is angled to assist wiring within limited space enclosures
• Ultra-Slim DIN Rail Mounting: Compact 12 mm width for standard 35 mm DIN rail installation — simultaneously makes a reliable IS earth connection when clipped onto the rail
• Dual-Stage Protection: Two stages of pulse-tested Zener diodes and an 'infallible' terminating resistor ensure continued safety if either stage should fail
• No Active Current Limiting Circuits: Pure passive design for maximum reliability — no active output current limiting circuits are employed

The MTL7767+ is a passive shunt-diode safety barrier that operates on the Zener barrier principle. It limits both voltage and current that can be delivered to a hazardous area circuit under fault conditions.

• Voltage limiting: Zener diodes clamp the output voltage to a safe level (15V) if the safe-area voltage rises above normal operating levels
• Current limiting: A series resistor (100Ω) limits fault current to a safe value (150mA)
• Fusing: Internal fuses provide backup protection under severe fault conditions
• Two-stage voltage limitation: Two stages of pulse-tested Zener diodes ensure continued safety if either stage should fail
• No active output current limiting circuits: Pure passive design for maximum reliability
• Grounding: The barrier requires a connection to a high-integrity earth ground — made simultaneously when clipping onto standard T-section DIN rail

The MTL7767+ is specifically designed for positive DC system protection in hazardous area installations:

• 12V DC proximity sensors
• Low-level DC switches and push buttons
• Digital input circuits in hazardous areas
• LED indicators
• Simple apparatus (switches, thermocouples, resistive sensors, photocells)

Contact our sales team for volume pricing, datasheet downloads, or technical application support.

The MTL7700 series offers a complete range of shunt-diode safety barriers for all intrinsic safety applications.