Wednesday, June 26, 2019

3 Phase Current Transformer Wiring Diagram

3 phase current transformer wiring diagram for 3 phase load (ampere) testing. As you know that we use the current transformer to measure the current. For testing the current (ampere) running to load we use two types of amp meter. In which one series type which is wired in series between load and supply. And 2nd is a current transformer type which is wired with a current transformer to measure the current. We can wire a current transformer for single phase and also for 3 phase. The current transformer is always used for line ampere testing. For 3 phase system ampere testing every Line has its own current transformer. And these current transformers further connected with a 3-ampere meter or one-ampere meter and ampere testing selector switch.

For better understanding also read below

How to wire current transformer with digital ampere meter
Ampere meter selector switch wiring with current transformers

How to 3 phase current transformer wiring diagram with ampere meter

Note that if your ampere meter is 100/5A then used only 100/5A ratio current transformer. In the below 3 phase current transformer wiring diagram with amp meter. 3 CT coil and Amp testing meters are shown. The current transformer wiring for each meter.

3 phase current transformer wiring diagram

You can wire the current transformer for three phase system as shown in the above diagram. However, if you want to test 3 phase ampere with an only one-ampere meter. Then use an ampere selector switch with the current transformer. For that, you need to wire all 3 current transformers with an amp selector switch. And from the selector switch, the two-wire supply will go to ampere meter. From the selector switch, you can test at each line(phase) ampere.


  1. Why is the one point of ammeter/ct connected together with each other.

  2. Amazing post, Which you have shared here about the 3 Phase Current Transformer Wiring. Your article is very informative and nicely describes the process of 3 Phase Current Transformer Wiring. I would like to thanks for sharing this article here. residential electricians near me


  4. Thanks for picking out the time to discuss this, I feel great about it and love studying more on this topic. It is extremely helpful for me. Thanks for such a valuable help again. ground fault current transformer