General
Degree of protection	Ex i
Number of conductors	2
Cross section	0,08-2,5 mm²
Colour	Blue

The WAGO 280-904 is a 2-conductor pass-through terminal block designed for use in explosion-protected installations according to the protection type Ex i. It enables the safe connection of two conductors in a pass-through concept, with the connection conductors attached from the front. The terminal block is finished in blue and is suitable for cross-sections from 0.08 to 2.5 mm². The width is 5 mm, making it suitable for use in standard rail systems.

Applications
This terminal block is specifically designed for applications in explosion protection technology, particularly for circuits complying with protection type Ex i. This includes, for example, installations in areas with explosive atmospheres, such as in the chemical industry, petrochemicals, or food processing. Use in such environments requires high electrical safety, which is ensured by the specific design of the terminal block.

Functions and Equipment in Detail
The 2-conductor pass-through terminal block 280-904 enables the connection of two conductors within a single component, with current flow passing through the terminal block. The connection conductors are inserted from the front, enabling quick and secure installation. The terminal block is designed for cross-sections from 0.08 to 2.5 mm², covering a wide range of conductor cross-sections commonly used in industrial electrical engineering. The blue color serves as a visual identifier and is standard for specific conductor functions.

Technology Explained Simply
The terminal block operates on the principle of a pass-through terminal block, where the electrical connection between two conductors is made via a common contact. The design ensures a secure and durable connection, even under the special requirements of explosion protection technology. The protection type Ex i (intrinsic safety) means that the terminal block is designed so that it does not act as an ignition source for an explosion under normal operating conditions. This is achieved by limiting electrical energy and specific design features. The terminal block is designed for mounting on a standard rail (e.g. 35 mm), enabling easy integration into existing control systems.

Compatibility and Accessories
The terminal block can be combined with various accessories that extend its functionality. These include, for example, insulation stops (280-470), partition panels (280-311), wire chain bridges (210-123, 709-110), wire end ferrules (216-201, 216-203, 216-101, 216-104), test plug and adapter modules (249-141, 249-106), LED and neon lamp modules (280-803/281-415, 280-803/281-418), end and intermediate plates (280-309), reducing cover plates (284-344), double label carriers (209-128), and box bridges (780-458, 780-455, 780-454). These components can be used depending on the application for identification, insulation, testing, or optical indication. Combination with rails (e.g. 210-197, 210-198) enables modular mounting in enclosures.

Mounting and Installation
Mounting is done on a standard rail (e.g. 35 mm), with the terminal block secured using an integrated rail retention profile. The connection conductors are inserted from the front into the terminal opening and tightened by turning the screw head. The specified cross-section range of 0.08 to 2.5 mm² must be observed to ensure a secure connection. Mounting requires no additional tools other than a screwdriver or suitable terminal block key.

Advantages in Operation
The terminal block provides a reliable and safe connection, especially in explosive environments. The pass-through design reduces the number of required components and simplifies circuit diagram management. The clear identification via the blue color supports quick recognition of the conductor function. Compatibility with a wide range of accessories allows flexible adaptation to specific requirements. Mounting is quick and requires no special tools, simplifying maintenance and servicing.