Eaton MTL MTL7728P+ ATEX Current Loop Barrier

The MTL7728+ is a high-performance 1-channel shunt-diode safety barrier (Zener barrier) from Eaton's Crouse-Hinds series MTL7700 range, specifically engineered for analogue and digital I/O applications 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 rated supply voltage of 28 V DC, safety description of 28 V, 300 Ω, 93 mA, and positive polarity configuration, the MTL7728+ is the ideal solution for protecting controller outputs, solenoids, proximity detectors, and switch inputs in Zone 0, 1, and 2 hazardous locations (gas groups IIC, IIB, IIA).

The device features a compact 12.6 mm width and standard DIN rail mounting for easy integration into existing control cabinets.

The "+" suffix indicates positive polarity, distinguishing it from negative polarity and AC versions. This model is the direct replacement for the discontinued MTL728+ from the MTL700 range.

• IIC Gas Group Certification: Certified for the most hazardous IIC gas groups (hydrogen, acetylene) — suitable for use in Zone 0, 1, and 2 explosive atmospheres
• 1-Channel General Purpose I/O: Single channel rated for 93 mA switching current — ideal for protecting controller outputs, solenoids, proximity detectors, and switch inputs
• 28 V Working Voltage: Provides safe voltage limiting for analogue/digital circuits, preventing ignition under fault conditions
• 300 Ω End-to-End Resistance: Matches typical loop resistance requirements for 4-20 mA signal circuits while ensuring intrinsic safety compliance
• 93 mA Maximum Current: Adequate current handling for most field instrumentation including transmitters, sensors, and switch inputs
• Replaceable Secondary Fuses: Features secondary replaceable fuses — useful where there is the possibility of faults occurring during commissioning
• 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: Integrated bussed power distribution reduces cabling requirements when used with the MTL7798 power feed module
• Angled Wire Entry: Wire entry is angled to assist wiring within limited space enclosures
• Ultra-Slim DIN Rail Mounting: Compact 12.6 mm width for standard 35 mm T-section DIN rail
• Dual-Stage Protection: Contains two stages of pulse-tested Zener or forward-connected diodes and an 'infallible' terminating resistor
• Direct Replacement for MTL700 Series: Compatible terminal numbering and safety descriptions allow direct replacement of older MTL700 series barriers
• Global Approvals: ATEX, IECEx, UL, CSA, FM, KOSHA (Korea), and LR Marine certifications for international installation flexibility

The MTL7728+ 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.

The MTL7728+ is specifically designed for general-purpose I/O protection in hazardous area installations:

• Solenoid valves (low-power)
• Proximity detectors (NAMUR)
• Switch inputs (limit switches, pressure switches)
• 2-wire transmitters (with bussed power)
• Analogue I/O circuits
• Conventional fire detectors

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