The MTL7700 Series of intrinsically safe passive network devices use zener diodes, resistors and fuses to safely divert excess electrical energy to ground and prevent sparking or overheating of equipment in hazardous areas.

The MTL7700 intrinsic safety device provides quick and easy installation and maintenance with removable terminals, the loop can be disconnect by simply unplugging the terminals from the side of the module. Wire entry is also angled to assist wiring within limited space enclosures.

DIN-rail mountable the MTL7700 intrinsic safety devices clamp simply and securely onto standard T-section DIN rail, simultaneously making a reliable intrinsically safe earth connection.

For applications where field device power is required for switch inputs or 2-wire transmitters, the MTL7700 barrier range provides a bussed power feed facility. When used in conjunction with the MTL7798 power feed module the user has a fully protected, electronically fused supply to many barriers with no additional wiring required.

All MTL7700 range zener barriers are based on the same simple principle. Each channel contains two stages of pulse-tested Zener or forward-connected diodes and an ’infallible’ terminating resistor. In the event of an electrical fault in the safe area, the diodes limit the voltage that can reach the hazardous area and the resistor limits the current. A fuse protects the diodes, and the two stages of voltage limitation ensure continued safety if either stage should fail. No active output current limiting circuits are employed. All models are certified ’ia’ for all zones and ’IIC’ for all explosive atmospheres (except MTL7707P+ and MTL7729P+, 'ia' 'IIB').

Intrinsically safe zener barriers
Standard DIN rail mount
Removable, colour-coded terminals
Bussed power feed to other modules
Solid state and relay switch modules
Choice of solid-state or relay output
Dual-channel variants - 6.3mm per channel
Proximity detector inputs
Direct replacement for MTL700 Series
Compatible terminal numbering and safety descriptions
Dimensions: 105 x 90 x 12.6mm

Power bus facility applicable to MTL7706+, 7741 and 7787+ barriers

BAS01 ATEX 7217

II 1 GD EEx ia IIC T6

Use this Zener barrier from Eaton to regulate the electrical energy supplied to a transmitter in a hazardous location. A maximum current consumption of 93mA (milliampere) and a supply voltage of 28V DC make it an energy-efficient option for your industrial setup. The unit has built-in overvolt protection, which prevents damage from faulty wiring and means you can use it with an unregulated power supply. Compatibility with DIN rail mounting makes installation straightforward and tool-free. A wide operating temperature range between -20°C and +65°C means this device can withstand demanding environments.

• Rugged design so it's safe to use in hazardous areas
• Terminals are colour-coded for easy identification during installation and maintenance
• Angled wire entry for ease of wiring in tight spaces

A Zener barrier typically consists of an output resistor, Zener diodes and a fuse. The Zener diodes limit the voltage supply by redirecting excess voltage to the ground while the output resistor modifies the current. The fuse protects the diode from current overload and short circuits.

Eaton formerly known as MTL