Original MTL7767+ 2-Channel Intrinsically Safe Relay Output Barrier with 15V Safety Description and IIC Gas Group Certification
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negotiable
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1
Delivery Time:
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Brand:
MTL
Product Description
Original MTL7767+ Intrinsically Safe Relay Output Barrier Hazardous Area Protection Module
Product Overview
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.
Model Number Decoding: MTL7767+
| Code Segment | Meaning |
|---|---|
| MTL | MTL Instruments Group (now Eaton) |
| 77 | MTL7700 series — Shunt-diode safety barriers |
| 67 | Specific barrier configuration for low-level positive DC systems |
| + | Positive polarity configuration |
The "+" suffix indicates positive polarity, distinguishing it from negative polarity versions and AC versions.
Key Features & Benefits
- 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
Technical Specifications
General Specifications
| Parameter | Value |
|---|---|
| Manufacturer | Eaton (Crouse-Hinds series MTL) |
| Series | MTL7700 Range |
| Product Model | MTL7767+ |
| Product Type | Shunt-Diode Safety Barrier (Zener Barrier) |
| Number of Channels | 2 (dual-channel) |
| Polarity | Positive (+) |
Electrical Ratings
| Parameter | Value |
|---|---|
| Safety Description | 15V, 100Ω, 150mA |
| Working Voltage (Vwkg) | 12V DC nominal (low-level DC systems) |
| End-to-End Resistance | 110Ω Min to 119Ω Max |
| Maximum Current | 150mA |
Test Specifications
| Test | Value |
|---|---|
| Terminal Voltage @ 10 µA | 12V Min to 13.6V Max |
| Terminal Voltage @ 20mA | 12.4V Min to 13.7V Max |
| Diode Test +ve | ∞ |
| Diode Test -ve | Vfz x 1 |
Hazardous Area Specifications
| Parameter | Value |
|---|---|
| Gas Groups | IIC, IIB, IIA |
| Zones | Zone 0, 1, 2 |
| Equipment Protection Level (EPL) | Ga, Gb, Gc |
| Certification | ATEX II (1) GD [Ex ia] IIC |
Mechanical Specifications
| Parameter | Value |
|---|---|
| Width | 12 mm |
| Height | 85 mm / 90 mm |
| Depth | 105 mm |
| Weight | 0.120 kg / 120 g |
| Enclosure Material | Polycarbonate |
| Mounting | DIN rail (35 mm T-section) |
| Terminals | Removable screw terminals |
Environmental Specifications
| Parameter | Value |
|---|---|
| Operating Temperature | -20°C to +60°C |
| Degree of Protection | IP20 |
Certifications & Approvals
| Certification | Status | Details |
|---|---|---|
| ATEX | ✅ Certified | BAS01 ATEX 7217 — II (1) GD [Ex ia] IIC |
| IECEx | ✅ Certified | International certification for explosive atmospheres |
| CCC Ex (China) | ✅ Certified | Available |
| RoHS | ✅ Compliant | Lead-free |
Function Description
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.
How it works:
- 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
Signal Flow
Safe Area (Control Side) Hazardous Area (Field Side)
PLC/DCS/Indicator ──► MTL7767+ ────► Intrinsically safe circuit
12V DC supply ──► (Voltage/Current limiting) ──► Low-level DC sensors/switches
(Zener diodes + 100Ω resistor)
[High-integrity earth ground required]
Applications
The MTL7767+ is specifically designed for positive DC system protection in hazardous area installations:
| Industry | Application |
|---|---|
| Oil & Gas | Low-level DC logic circuits and sensor inputs on offshore platforms and refineries |
| Chemical Processing | 12V DC control circuits, digital input protection in explosive atmospheres |
| Pharmaceutical | Low-voltage DC systems for batch processing equipment requiring Ex protection |
| Factory Automation | 12V DC proximity sensors, limit switches, and digital I/O protection |
| Power Generation | Turbine control systems with low-level DC inputs |
| Marine & Offshore | Marine control systems requiring intrinsic safety certification |
Typical field devices connected:
- 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)
Why Choose the MTL7767+?
Optimized for 12V DC Systems — Specifically designed for positive DC systems up to 12V DC, the MTL7767+ provides the precise voltage and current limiting characteristics required for low-level logic circuits.
2-Channel Efficiency — With two independent channels in a single compact 12 mm housing, the MTL7767+ protects two field devices while using minimal panel space.
Unique Removable Terminals — Unlike competitors, the MTL7767+ features removable terminal blocks that simplify cabling, maintenance, and barrier replacement without rewiring. The terminals can be unplugged from the side of the module for loop disconnect.
Bussed Power Capability — Integrated bussed power distribution reduces cabling requirements and installation costs — a unique feature of the MTL7700 series.
Compatibility with MTL7764+ — The MTL7767+ and MTL7764+ are designed to work together in IIC environments, providing complete low-voltage DC system protection.
Dual-Stage Protection — Each channel contains two stages of pulse-tested Zener diodes and an 'infallible' terminating resistor. The two stages of voltage limitation ensure continued safety if either stage should fail.
Pure Passive Design — No active output current limiting circuits are employed — pure passive design for maximum reliability and long service life.
Proven MTL Heritage — Since its introduction in 1984, the MTL700 range established itself as the worldwide standard for safety barriers. The MTL7700 range follows closely in its footsteps, providing quick and easy DIN rail installation.
Simple Installation — DIN rail mounting with simultaneous IS earth connection, clearly labeled terminals, removable terminal blocks, and compact 12 mm width make installation quick and intuitive.
MTL7767+ vs. Related MTL7700 Series Models
| Model | Channels | Working Voltage | Resistance | Current | Polarity | Primary Application |
|---|---|---|---|---|---|---|
| MTL7767+ | 2 | 12V | 100 Ω | 150mA | Positive (+) | 12V DC positive systems |
| MTL7764+ | 2 | 12V | 1,000Ω | 12mA | Positive (+) | Strain-gauge bridges |
| MTL7722+ | 2 | 18V | -- | -- | Positive (+) | 18V DC systems |
| MTL7706+ | 1 | 28V | 300Ω | 93mA | Positive (+) | General purpose positive polarity |
| MTL7765ac | 2 | 28V | 300Ω | 93mA | AC | AC/DC high voltage systems |
| MTL7778ac | 2 | 28V | 600Ω | 47mA | AC | AC/DC systems, common-mode voltage |
Installation Information
| Parameter | Detail |
|---|---|
| Mounting | Standard 35 mm T-section DIN rail (EN 60715) |
| Terminals | Removable screw terminals |
| Grounding | High-integrity earth connection made simultaneously when clipping onto DIN rail |
| Wire Entry | Angled to assist wiring in limited space enclosures |
| Clearance | Minimal — 12 mm width enables high-density installation |
| Operating Position | Any orientation |
Important Installation Notes:
- A high-integrity earth ground connection is mandatory for proper Zener barrier operation
- Do not install in areas where condensation may occur
- The barrier must be installed in a safe area (non-hazardous location)
- The MTL7767+ and MTL7764+ can be safely used together in IIC environments
Ordering Information
| Item | Details |
|---|---|
| Part Number | MTL7767+ |
| Brand | Eaton (Crouse-Hinds series MTL) |
| Product Family | MTL7700 Range — Shunt-Diode Safety Barriers |
| Tariff Code | 85369095 |
| Weight | 0.120 kg (120 g) |
| Country of Origin | India / UK |
| Condition | New, Original, Factory Sealed |
| Minimum Order Quantity | 1 piece |
| Warranty | Manufacturer's standard warranty |
| Shipping | Immediate dispatch via DHL, FedEx, UPS, TNT |
Contact our sales team for volume pricing, datasheet downloads, or technical application support.
Related Products from MTL7700 Series for Low-Voltage DC Applications
| Model | Function | Description |
|---|---|---|
| MTL7767+ | Low-Voltage DC Barrier | 15V, 100 Ω, 150mA — 2-channel, positive polarity for 12V DC systems |
| MTL7764+ | Low-Voltage Sense Barrier | 15V, 1,000Ω, 12mA — for logic return signals |
| MTL7722+ | 18V DC Barrier | 18V DC systems |
| MTL7706+ | Single-Channel Barrier | 28V, 300Ω, 93mA — general purpose positive polarity |
| MTL7787+ | Dual-Channel Barrier | 28V, 300Ω, 93mA — general purpose positive polarity |
| MTL7798 | Power Feed Module | Provides bussed power distribution for PAC series barriers |
The MTL7700 series offers a complete range of shunt-diode safety barriers for all intrinsic safety applications.
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Company
Shenzhen Hengyo Power Technology Co., Limited
Location
Room 2407, B Block No.145 Chengshi Zhuchang Bld, Bagua 2nd Rd, Futian Dist. Shenzhen City, China 518029
Contact Person
Vivian Chan