MTL7755AC Eaton MTL RTD Zener Safety Barrier

The MTL7755AC is a high-performance 2-channel shunt-diode safety barrier (Zener barrier) from Eaton's Crouse-Hinds series MTL7700 range, specifically engineered for 2-wire and 3-wire floating bridge RTD 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 safety description of 3V, 10 Ω, 300mA, the MTL7755AC is the ideal solution for protecting Pt100, Pt500, and Pt1000 RTD sensors in Zone 0, 1, and 2 hazardous locations (gas groups IIC, IIB, IIA).

The "AC" suffix indicates a non-polarized barrier suitable for both AC and DC circuits, distinguishing it from polarity-sensitive models. This model is specifically designed for 2-wire and 3-wire RTDs (floating bridge).

• 2-Channel Efficiency: Two independent intrinsically safe channels in a single compact housing — protects two RTD sensors while using minimal panel space
• Floating RTD Optimization: Specifically designed for floating bridge RTD applications — ideal for Pt100, Pt500, Pt1000 2-wire and 3-wire RTD temperature sensors
• Low-Voltage/High-Current Design: Safety description of 3V, 10 Ω, 300mA — perfect for low-voltage temperature sensing applications requiring higher current
• 2-Wire or 3-Wire RTD Support: Flexible configuration for 2-wire or 3-wire RTD connections — compensates for lead resistance for accurate temperature measurement
• AC/DC Compatibility: Non-polarized operation eliminates wiring errors — no need to worry about positive or negative polarity connections
• 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
• Angled Wire Entry: Wire entry is angled to assist wiring within limited space enclosures, making installation easier in crowded control cabinets
• Ultra-Slim DIN Rail Mounting: Compact 12.6 mm width for standard 35 mm T-section DIN rail — simultaneously makes a reliable IS earth connection when clipped onto the rail
• Dual-Stage Protection: Each channel contains two stages of pulse-tested Zener or forward-connected diodes and an 'infallible' terminating resistor
• Direct Replacement for Obsolete Models: Compatible terminal numbering and safety descriptions allow direct replacement of older barriers: MTL105, MTL155, MTL156, MTL755AC
• Global Approvals: CCC Ex (China valid until 2030-09-01), ATEX (BAS01 ATEX 7217), IECEx, UL, CSA certifications for international installation flexibility

TIIS certification expired July 2, 2024. CCC Ex certification is valid until September 1, 2030.

The MTL7755AC 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 MTL7755AC is specifically designed for floating RTD temperature measurement protection in hazardous area installations: