In today's fast-evolving electrical and industrial landscape, precision and reliability in wiring solutions are more critical than ever. Terminal blocks are commonly used for signal connections or power distribution within a control panel. A terminal block is like 'LEGO' for the engineering world—connecting and organizing with precision.
In this article, we will focus on a specific terminal block product range from Weidmüller. Recently, Ultech Engineering attended a Weidmüller webinar introducing one of their key application ranges from Transformer Terminal Block (TTB) —Instrument Transformer Wiring—or transducer wiring and how their Klippon Connect Terminal Block is designed to streamline and optimize this essential process.
Instrument transformer wiring refers to the electrical connections and configurations used to install and integrate instrument transformers—such as current transformers (CTs) and voltage transformers (VTs), also known as potential transformers (PTs)—into a power system. These transformers are essential for stepping down high voltage and current levels to safer, measurable values, enabling accurate metering, protection, and control of electrical systems.
Instrument transformer wiring is crucial in power distribution and industrial automation, ensuring accurate measurement, protection, and control. However, traditional wiring methods often pose challenges such as complex installations, safety risks, and maintenance difficulties. Weidmüller’s Klippon Connect addresses these concerns with innovative design features that improve efficiency, safety, and ease of use.
This article explores the Klippon Connect Terminal Block's capabilities, its role in instrument transformer wiring, and the key takeaways from Weidmüller’s presentation.
Correct wiring adheres to industry standards (e.g., IEC, IEEE, ANSI), ensuring compatibility and reliability in electrical installations.
Ensures precise voltage and current readings for metering and monitoring power system performance.
Facilitates the operation of protective relays, preventing damage to electrical equipment and enhancing personnel safety.
Provides electrical isolation between high-voltage circuits and measuring/control devices, reducing the risk of electrical hazards.
Proper wiring ensures reliable signal transmission to relays and meters, supporting stable and efficient power system operation.
In modern industrial and automation environments, efficient and reliable electrical connections are critical for operational success. Weidmüller’s Klippon® Connect Terminal Blocks provide a comprehensive solution tailored to various applications, from signal wiring to power distribution, shielding, and earthing. Designed for seamless integration into control cabinets, the Klippon Connect range enhances efficiency, safety, and flexibility across diverse electrical systems.
With optimized solutions for PLC I/O, DCS I/O, voltage distribution, and transformer wiring, Klippon Connect ensures that electrical connections remain robust, organized, and future-ready. Whether in building installations, instrumentation, or power feed-in applications, these terminal blocks deliver superior performance while reducing wiring complexity and maintenance efforts. However, this article focuses primarily on Instrument Transformer Wiring.
Weidmüller offers a variety of connection technologies designed for safe, efficient, and precise wiring of current and voltage transformers. These solutions ensure error-free installation, reliable operation, and long-term performance in energy monitoring applications.
✔️Fast and tool-free wiring with direct insertion of conductors
✔️High vibration resistance, ensuring secure connections
✔️Reduced wiring time, improving installation efficiency
✔️Proven reliability with a strong mechanical connection
✔️Easy maintenance with simple re-tightening when needed
✔️Ideal for harsh environments, ensuring long-term durability
✔️Combines PUSH IN and screw connections for maximum flexibility
✔️Allows for different wiring methods within the same terminal block
✔️Versatile solution for varied installation requirements
In current transformer circuits, the ATTB 6 PG CT is equipped with a specially designed 2 and 3-pole self-shorting pluggable to guarantee a Make Before Break (MBB) contact under every handling condition.
✔️Data-supported accessory selection via Weidmüller Configurator (WMC)
The complete provision of data in the WMC enables a straightforward selection of safety-critical accessories and safe and rational product configuration.
✔️Maximum function density
The new transformer terminal blocks of the TTB range are particularly compact and offer outstanding functional density compared to other solutions on the market.
✔️Dedicated cross-connection channel
A cross-connection channel, upstream and downstream of the disconnect point, ensures maximum flexibility during installation. Neither the short-circuit function of current transformers nor the testing possibilities are limited. In this way, even more complex circuit requirements can be realized with the same standardized accessories.
In current transformer circuits, the ATTB 6 PG CT is equipped with a specially designed 2 and 3-pole self-shorting plugable to guarantee a Make Before Break (MBB) contact under every handling condition.
The ATTB 6 PG pluggable terminal blocks are designed for instrument transformer circuits, ensuring secure and efficient connections. In current transformer (CT) applications, the ATTB 6 PG CT features specially designed 2- and 3-pole self-shorting terminal blocks, guaranteeing a reliable make-before-break (MBB) contact under all handling conditions. For voltage transformer (VT) circuits, the ATTB 6 PG VT includes a simple feed-through plug, offering the same ease of handling and safety. Both CT and VT plugs are fully coded to prevent mismating, enhancing system reliability and operational safety.
In current transformer circuits, the ATTB 6 PG CT is equipped with a specially designed 2 and 3-pole self-shorting plug to guarantee a "make before break" (MBB) contact in all handling conditions
For voltage circuits, a simple feed-through plug offered with the ATTB 6 PG VT guarantees the same ease of handling and safety, which is also required for voltage circuits.
Uniform accessories from the PUSH IN A-Series reduce inventory costs and increase productivity in production.
Weidmüller has developed a series of test-disconnect terminal blocks for current and voltage transformer wiring. These terminal blocks address key challenges by offering safe, efficient, easy-to-use instrument transformer connection solutions. Disconnect terminal blocks, test disconnect terminal blocks, and N-disconnect terminal blocks for testing and measuring circuits during maintenance work or normative requirements. They are commonly used in applications such as energy meters, relays, and control panels.
Test disconnect terminal blocks come in various types, including standard disconnect terminals and those specifically designed for instrument transformer wiring (ITW). Instrument Transformer Wiring terminal blocks are a specialized subcategory used for connecting current transformers (CTs) and voltage transformers (VTs) in protection and metering circuits. Instrument Transformer Wiring (ITW) is a specialized subset of Test Disconnect Terminal Blocks, each serving distinct roles within the category.
| Test-Disconnect Terminal Blocks | Instrument Transformer Wiring Terminal Block |
| Enables safe testing, isolation, and maintenance of electrical circuits. | Specifically designed for connecting current transformers (CTs) and voltage transformers (VTs) in protection and metering circuits. |
| Used in energy meters, relays, and general control circuits. | Used in CT and VT circuits for power system protection and monitoring. |
✔️Ensures that the current transformer is short-circuited during disconnection before being removed from the circuit.
✔️Prevents hazardous voltage spikes in the secondary winding.
✔️Enhances operational safety by protecting measuring devices and personnel.
✔️Positioned upstream and downstream of the disconnect point.
✔️Allows safe and convenient testing without requiring additional tools.
✔️Reduces downtime and simplifies maintenance.
✔️Prevents loss of critical components during installation and servicing.
✔️Enhances durability and long-term reliability.
✔️Ensures easy identification of the connection and disconnect status.
In-application measurements and the protection of such measurements are among the main functions in the energy sector. Measuring devices require regular maintenance to remain informative and can continue to be used reliably in the industry.
Protection relays have an extremely important and critical function in T&D grids since they have to detect and isolate faults in the shortest possible time. Their connection with current transformers and voltage converters not only has to be RELIABLE but must also be SIMPLE and SAFE. Simplicity is extremely important when it comes to the design/standardization of the required protection circuits (engineering phase). In addition, safety is crucial to avoid potential human errors during maintenance operations that adversely affect personnel or devices. Our instrument transformer terminal blocks make this possible.
Indirect and semi-direct measurement applications also require reliability, simplicity, and safety in the connections with current transformers and voltage converters. However, special features of this application mean that a certain flexibility is required. This might affect safety (e.g. the connection of a sample series ammeter from time to time). The instrument transformer terminal blocks in our Klippon® TTB range also cover the specific requirements of measurement connections. We offer the right solutions for performing all necessary tests with our instrument transformer terminal blocks – without negatively affecting the safety of personnel and devices.
Weidmüller test-disconnect terminal blocks, available with both spring and screw connection technology, ensure safe and efficient wiring for current and voltage transformer applications. To support seamless installation and operation, a range of standard accessories is available, including reliable lockout devices, captive components, and data-supported accessory selection via Weidmüller Configurator. These accessories enhance flexibility by enabling a make-before-break (MBB) function through either a lever or plug, ensuring precise and secure measurement of current, voltage, and power in transformer circuits.
The short current bridges are inserted into two instrument transformer wiring terminal blocks. The short-circuit bridge allows the desired short-circuit to be realized within the application for maintenance work.
The test socket is used to connect test devices with a standard 4.0 plug. Depending on the potential within the application, different colors of the test sockets can be selected for quick and easy maintenance work.
Current and voltage transformer wiring
Weidmüller test disconnect terminal blocks featuring spring and screw connection technology allow you to create all the important converter circuits for measuring current, voltage, and power in a safe and sophisticated way.
Fixing screws fix the short current bridge within the application. If the short current bridge is slid between two adjacent terminal blocks into the short circuit position, it can be fixed using a fastening screw. This ensures a permanent connection or short circuit.
Current and voltage transformer wiring
Weidmüller test disconnect terminal blocks featuring spring and screw connection technology allow you to create all the important converter circuits for measuring current, voltage, and power in a safe and sophisticated way.
The switch lock can be easily inserted into the terminal from above. The switch lock prevents the unauthorized opening or closing of circuits as it blocks the disconnect lever in its respective position.
Weidmüller’s Instrument Transformer / Modular Test-Disconnect Terminal Blocks offer a comprehensive and reliable solution for secure transformer wiring in measurement and protection applications. Designed with safety, efficiency, and ease of use, these terminal blocks incorporate essential features such as MBB (Make-Before-Break) contact mechanisms, integrated test sockets, and versatile connection technologies. They enhance system performance by simplifying maintenance, minimizing wiring errors, and optimizing space utilization while ensuring compliance with stringent industry standards. With Weidmüller’s innovative wiring solutions, industries can achieve precise metering, robust protection, and long-term operational reliability in energy distribution networks.
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