Description

The MTL 8604-FT-FU is a robust field termination assembly engineered for hazardous-area signal conditioning in industrial automation systems. As part of Eaton’s MTL Instruments FTA (Field Termination Assembly) series, this solution integrates flameproof (Ex d) and fused protection technologies to safely interface field instruments with control systems in Zone 1/21 and Division 1 environments. The 8604-FT-FU supports up to four channels, providing galvanic isolation and energy limitation for analog/digital signals (4–20mA, HART, discrete I/O) while preventing fault propagation between circuits. Its stainless-steel housing (IP66-rated) withstands corrosive atmospheres and mechanical stress, making it ideal for oil refineries, chemical plants, and offshore platforms where explosive gases or dusts exist.

Designed for rapid deployment, the MTL 8604-FT-FU features plug-and-play modules with screwless terminations, reducing installation time by 40% compared to traditional marshalling cabinets. The integrated fuses (FU suffix) offer overcurrent/short-circuit protection up to 250V AC/DC, while Ex d containment ensures internal explosions do not ignite external atmospheres. Compatible with MTL’s FTA bases and surge protectors, the 8604-FT-FU simplifies compliance with IEC 60079, ATEX, and NEC standards. For engineers seeking reliability in extreme conditions, this assembly delivers seamless signal integrity and failsafe hazard mitigation.

MTL 8604-FT-FU

Technical Specifications

Parameter Name	Parameter Value
Product Model	8604-FT-FU
Manufacturer	MTL Instruments (Eaton)
Product Type	Hazardous-Area Field Termination Assembly
Hazardous Certifications	ATEX/IECEx Ex d IIC T6 Gb, Ex tb IIIC T80°C Db
Input Channels	4 (individually isolated)
Protection Level	IP66 (NEMA 4X)
Fuse Rating	250 mA, 250 V AC/DC (per channel)
Terminal Voltage	250 V AC/DC max
Operating Temperature	-40°C to +80°C (-40°F to 176°F)
Housing Material	316L Stainless Steel
Ingress Protection	IP66 (dust/water jet resistant)
Dimensions (H x W x D)	225 x 45 x 125 mm (8.9 x 1.8 x 4.9 in)
Weight	1.8 kg (4.0 lb)
Compliance Standards	IEC 60079-0/1, EN 60079-31

Main Features and Advantages

Dual-Layer Hazard Protection: The 8604-FT-FU combines flameproof enclosure (Ex d) with fused intrinsic safety (Ex i). Each channel’s current-limiting fuse prevents excess energy transmission to hazardous areas, while the Ex d housing contains internal arcs – enabling use in Zone 1 gas and Zone 21 dust environments without additional enclosures.

Plug-and-Play Modularity: Tool-less module insertion into FTA bases (e.g., MTL 8581) allows on-site reconfiguration. Replace fuses or channels in <2 minutes without de-energizing the entire assembly, minimizing maintenance downtime.

Signal Integrity Assurance: Low-impedance (<0.1Ω) gold-plated contacts maintain signal accuracy for HART communication. Electromagnetic shielding rejects 20 kV/m RF interference, critical for noisy environments like compressor stations.

Corrosion Resistance: 316L stainless-steel construction resists sulphide stress cracking (SSC) in sour gas applications. Sealed conduits (M20x1.5/NPT) prevent moisture ingress in coastal installations.

Application Field

The MTL 8604-FT-FU excels in high-risk process industries requiring uncompromised safety. In LNG terminals, it interfaces cryogenic temperature sensors (e.g., Rosemount 3144P) with DCS systems, ensuring SIL 2 compliance for tank overfill protection. Petrochemical plants deploy the 8604-FT-FU for reactor pressure transmitters, where its Ex d rating mitigates hydrogen explosion risks.

For mining conveyors, the assembly isolates belt-speed sensors in Zone 21 coal-dust areas, while offshore rigs use it to condition subsea wellhead valve position signals. Pharmaceutical batch reactors leverage the MTL 8604-FT-FU’s HART transparency for remote calibration of Coriolis flowmeters in solvent-handling zones. In wastewater treatment, it protects level transmitters from methane explosions in digesters.

MTL 8604-FT-FU

Related Products

MTL 8581-BF: Flameproof base for mounting 8604-FT-FU modules.

MTL 7786+: Zener barrier for Zone 0/20 applications.

MTL 5541: Isolator for thermocouple/RTD signals.

MTL 9350: Surge protector for lightning-prone sites.

MTL 9360: Fieldbus FOUNDATION H1 termination.

MTL FTA-PS: DIN-rail power supply for FTA systems.

MTL FTA-FUSE: Replacement fuse kit for 8604-FT-FU.

MTL 5900: Remote I/O system for modular integration.

Installation and Maintenance

Pre-installation preparation: Verify area classification matches Ex d IIC/IIIC ratings. Use only certified M20/NPT cable glands with “Ex d” markings. Torque gland nuts to 25 N·m for gas sealing. Ensure conduit runs slope downward to prevent condensation accumulation near the 8604-FT-FU.

Maintenance recommendations: Inspect housing seals annually for UV degradation or chemical damage. Check fuse continuity monthly using a calibrated multimeter. Replace fuses only with identical MTL-specified parts (250mA, 250V). After servicing, conduct dielectric strength tests (500 V AC for 1 min) per IEC 60079-0. Never open the 8604-FT-FU in a hazardous area – remove to safe zone for maintenance.