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Connectwell Disconnect and Test Terminal Blocks Make Testing of Electrical Circuits Easy and Safe
October 2022

For applications that require frequent on-site testing, Disconnect & Test Terminal Blocks are used to provide convenient access to Ammeters, KWH Meters, Maximum Demand Indicators, Trivector Meters, Relays and Instrument Transformers, without removing the load and avoiding CT open circuit hazards.

A safe and simple way to disconnect and test


Test Terminal Blocks have amechanism that allows technical personnel to disconnect and reconnect the contacts inside the Terminal Block. Disconnect Terminal Blocks are used for disconnecting the secondary side of CT for measurement, meter testing and regulatory purposes. The disconnection in the circuit is achieved by means of the various mechanisms like lever type contacts or screw type contacts or sliding type contacts.


Measuring made easier under live conditions

Disconnect and Test Terminal Blocks can be used in low voltage current transformer and metering applications to safely disconnect the circuit. In these types of applications, primary current is provided to a  current transformer so as to step down the high current to 5A or 1A secondary current. This step down current is provided to the measuring meter, whether it is an analog or digital type meter. 


It is recommended that  a Connectwell Disconnect and Test Terminal Block (CDS6U, CDS6U/SC, STH4DT, CDTTU) is used between the current transformer and the meter. Above mentioned disconnecting terminals  can offer solutions during testing of meter and current transformer, however  should any fault occur or incorrect measurement is noted it will be displayed on the meter. 




Connectwell Disconnect and Test Terminal Test Socket as accessories (TPSLS) provide an easier way to measure the voltage and current (with help of testing probes) under live conditions.






Always remember that if there is current flowing in the primary circuit, the secondary circuit should never be opened. The primary's Ampere-Turns, which begins magnetizing the core, might cause extremely high voltage peaks while serving as a transformer and may cause high voltage hazard at open connections.


It is recommended that personnel involved in operations use specially designed Slide Shorting Link (SLS) or pluggable shorting plugs and Short the secondary side of the current transformer to avoid high voltage hazard. After shorting the secondary side of CT personnel can safely  operate the slide disconnect with a simple screw-driver .




How to test and measure more effectively

When testing the meter for any incorrect readings, use an external power source and test the meter at the secondary side of the current transformer with the help of a test socket (TPSLS). 




Using an external power supply, can help decide on whether the meter needs to be re -calibrated or replaced.  





The meter reading can be also compared with another meter.





For single phase applications use 2 Disconnect and Test Terminals for testing the single phase current measurement, using one current transformer. 




For three-phase and three-wire star connection use 6 Disconnect and Test Terminals for  testing a three phase current measurement  using   3 (three) current transformers.



For three-phase, four-wire delta connection to measure power and energy using multi-function meters, use 10 Disconnect and Test Terminals for connecting  three phase current measurement using 3 current transformers and three-phase voltage L1, L2 and L3 measurement and one neutral connection.


Switch to the modern standard for measuring and testing applications

When it comes to the modern method of measuring and testing voltage and current, using meters and current transformers, you can ensure a higher level of safety, security and operational convenience by choosing Connectwell Disconnect and Test Terminal Blocks. 

For more information or to discover the effectiveness of Connectwell Disconnect and Test Terminal Blocks, contact us today.



Connectwell, your right connection partner

With more than 15 international product certifications backed by the most stringent quality standards, our products pass through more than 40 quality assurance tests. This has ensured a ready acceptance of Connectwell terminal blocks across 80+ countries and in thousands of projects and applications worldwide.

Through our 4 decades of experience with state-of-the-art operations which are ISO certified, Connectwell has grown to become one of the leading manufacturers of terminal blocks in the world.

More than 1 million connections are made every day across the globe with Connectwell terminal blocks, making Connectwell a synonym for… the right connection.

So, if you would like to build your projects with a solution that can accommodate both dense and simple wiring, while saving panel space, ensure that you select Connectwell Multiple Level Terminal Blocks and get the added flexibility you need.

To know more about how Connectwell can contribute to your applications, please reach out to us at or +912517120600 / +912516762600


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