General
Terminal type	3-wire protective earth terminal
Conductor cross section	0,08–2,5 mm²
Colour	Green-yellow
Text	Centrical
DIN rail	35 x 15 mm and 35 x 7.5 mm
Connection technology	CAGE CLAMP®

The WAGO 280-687 is a 3-conductor protective earth terminal block, specifically designed for use in electrical installations to safely and reliably connect protective earth (PE) conductors. The device is coloured green-yellow, matching the international identification for protective earth conductors, and features a central labelling for clear identification of connection points. The terminal block is designed for mounting on support rails with dimensions 35 x 15 mm and 35 x 7.5 mm, enabling universal installation in standard switchgear. The connection technology is based on the CAGE CLAMP® system, which enables a secure, permanent, and resistance-free connection without additional tools. The terminal block is rated for a conductor cross-section up to 2.5 mm², with a minimum cross-section of 0.08 mm².

Applications
This terminal block is used in industrial and commercial electrical installations where secure connection of protective earth conductors is required. It is suitable for applications in enclosures, distribution boxes, and other electrical distribution units, where grounding of devices and switching equipment must comply with applicable safety standards. Its use in building electrical engineering, machine construction, and automation technology is common.

Functions and Equipment in Detail
The 3-conductor protective earth terminal block allows simultaneous connection of three individual conductors at one connection point. The central labelling facilitates assignment and documentation of connections, especially in complex switchgear. The CAGE CLAMP® system ensures an automatic, force-locked connection as soon as the conductor is inserted into the terminal block. The terminal block is rated for a maximum cross-section of 2.5 mm², making it suitable for a wide range of applications in low-voltage technology. The green-yellow colouring corresponds to the international standard for identifying protective earth conductors.

Technology Explained Simply
The CAGE CLAMP® system operates without tools: the conductor is simply inserted into the terminal block, where a movable contact arm automatically encloses the conductor and establishes a secure connection. The terminal block is designed to maintain the connection even under vibration and mechanical stress. The use of green-yellow as the colour coding is a clear identification in accordance with DIN VDE 0100-510, ensuring the protective earth conductor is clearly identifiable. The central labelling allows for clear assignment of connections, which is beneficial during maintenance and inspections.

Compatibility and Accessories
The terminal block is suitable for support rails with dimensions 35 x 15 mm and 35 x 7.5 mm, enabling mounting on standard support rails in the electrical industry. As accessories, various bridging elements are available, such as the box bridge 780-456 or the wire chain bridge 709-112, which allow connection of multiple terminal blocks. Additionally, wire end ferrules such as 216-102 or 216-104 can be used to protect conductor ends and ensure a clean connection. Labelling systems such as the WMB system (e.g. 793-5501) can be used for individual identification of connections.

Mounting and Installation
Mounting is done by simply clipping the terminal block onto the support rail. The terminal block fits securely and cannot accidentally slip off. Connection of conductors is achieved by inserting the conductor into the terminal block — the CAGE CLAMP® system ensures an immediate, secure connection. The terminal block is intended for use in enclosed switchgear, and mounting should be done in a dry, dust-free environment. Tools are not required, as the connection technology operates without tools.

Advantages in Operation
The terminal block provides a reliable, resistance-free connection that remains stable even under mechanical stress. The tool-free mounting reduces installation time and minimizes error sources. Clear identification through colour and labelling facilitates maintenance and inspection. Compatibility with standard support rails and the availability of accessories such as bridges and labelling systems increase flexibility in planning and executing electrical installations.