Inst ToolsInst ToolsInst Tools
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Search
  • Books
  • Software
  • Projects
  • Process
  • Tools
  • Basics
  • Formula
  • Power Plant
  • Root Cause Analysis
  • Electrical Basics
  • Animation
  • Standards
  • 4-20 mA Course
  • Siemens PLC Course
Reading: What is an Insulation Resistance Test? – Types, Applications
Share
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • Design
  • PLC
  • Interview
  • Control System
Search
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Common > What is an Insulation Resistance Test? – Types, Applications

What is an Insulation Resistance Test? – Types, Applications

This article provides an overview of an Insulation Resistance test, types of testing and its Advantages, & Applications.

Last updated: March 17, 2023 1:46 pm
Shiv Kumar
Common
1 Comment
Share
8 Min Read
SHARE

This article provides an overview of an Insulation Resistance test and its Advantages, & Applications.

Contents
What is Insulation Resistance Testing?Principle of Insulation Resistance TestingWhy is an Insulation Resistance Test Required?How Do You Measure Insulation Resistance?Testing of InsulationTypes of Insulation Resistance TestsShort-Time or Spot-Reading TestTime-Resistance MethodDielectric Absorption RatioAdvantages of Insulation Resistance TestApplications of Insulation Resistance Test

The insulation resistance test is not the most recent, but it is the most commonly used to determine the reliability of cables or windings within transformers, switchgear, motors, and electrical installations.

Insulation Resistance measurement is a common test performed on various types of cables and electrical wires.

This test is commonly used as a customer acceptance test, similar to a production test, with minimum insulation resistance for each unit length frequently specified by the customer.

The installation of the device, the type of usage, and the operating conditions are all factors that influence the IR test.

What is Insulation Resistance Testing?

The insulation resistance test definition is the measurement of total resistance between any two points separated by electrical insulation. The megger test is another name for this test. As a result, this test is used to determine how effective the dielectric or insulation is at restricting the flow of electric current.

Insulation Resistance tests are very useful not only for verifying insulation quality when the product is manufactured, but also when the product is used over time.

Principle of Insulation Resistance Testing

The insulation resistance test principle is to measure the steady-state leakage current with a voltage and then divide the voltage by the current (R = V/I).

If the IR meets or beats the required value, the IR test is successful.

The target insulation resistance of the measurement can be calculated by measuring the flow of current to the target after the voltage ‘V’ is applied, and then dividing the applied voltage ‘V’ by the resulting current ‘I’.

Why is an Insulation Resistance Test Required?

Once an electric current is supplied through a conducting wire to its destination, there is a loss of electric current along the way for various reasons.

As a result, we must conduct insulation testing to determine whether or not there is any current leakage, as this leakage could be extremely dangerous.

This testing is critical for avoiding injury and damage.

As a result, this test should be performed to ensure the dependability of the electrical equipment.

By performing this test, we can determine if the electrical equipment is in good condition and approximate the service life of the insulation. Insulation testing should be performed while repairing new electrical equipment so that while testing electrical equipment, we can ensure that the insulation is in good working order.

How Do You Measure Insulation Resistance?

Insulation Resistance Test

Ohms Law can be used to calculate insulation resistance.

If we apply a voltage across a resistor, we can calculate the current flow using the formula R=V/I. This is a fundamental technique; we should be aware of various types of current such as capacitive charge, polarization, leakage, and conduction current.

An insulation resistance tester can be used to measure insulation resistance. This tester has three terminals, two of which are simply connected to a circuit to perform the test and the third to a guard terminal.

This terminal is used to select specific electrical components within large plant machinery.

Testing of Insulation

The following procedure dissipates testing of insulation.

Before using the megger instrument, we must determine whether it provides an infinity value when not connected and a zero value when the two terminals are connected and the handle is turned.

To perform an insulation resistance test, make sure the cable is disconnected from any devices and that there is no eddy current within the device by grounding it.

Because resistance is proportional to temperature, the instrument must be at its normal operating temperature.

Check that both ends of the cable are separated from one another. Connect the megger’s two terminals to the conductors to be tested. If the reading is infinite, the conductor’s insulation is adequate.

This test is important because it determines the dependability of the insulation between conductors. This test aids in the detection of short circuits within the circuit.

Types of Insulation Resistance Tests

Generally, we know that this Insulation Resistance Test is conducted by using a megger or mega-ohm meter.

Insulation Resistance Tests can be classified into three types as

  1. Short-Time or Spot-Reading Test
  2. Time-Resistance Method
  3. Dielectric Absorption Ratio

Short-Time or Spot-Reading Test

The Short-Time or Spot-Reading test is as simple as connecting a Megger device across the insulation to be tested.

Following that, it is used for a short period, usually 60 seconds. It is critical to remember that humidity, temperature, and insulation conditions all have an impact on the reading.

Time-Resistance Method

The Time-Resistance testing method frequently yields conclusive results with no prior test results. This test is primarily dependent on good insulation absorption compared to contaminated insulation.

Throughout the insulation test, a device such as Megger will take straight readings at specific times and record the differences. If the insulation is good, this type of time resistance test should show a consistent increase in resistance over a set period.

Dielectric Absorption Ratio

Dielectric Absorption Ratio is the ratio of two time-resistance readings, and it is extremely useful for recording insulation data. A one-minute reading, for example, can be divided by 30 seconds of reading; thus, a Megger device will make this test easier and provide the best results.

So, while this device can run for one minute, it also allows you to take readings every 30 seconds and every minute.

Advantages of Insulation Resistance Test

  • The following are some of the benefits of the insulation resistance test.
  • The insulation resistance test determines how effective the insulation is at limiting current flow.
  • These tests are extremely useful for determining the quality of insulation.
  • To avoid electrical shocks, this test is recommended.
  • It is a quality control measure used during the manufacturing of electrical equipment.

Applications of Insulation Resistance Test

  • The following are examples of insulation resistance test applications.
  • This test is performed to avoid hazards such as short circuits and electric shocks caused when the insulation within electrical devices, equipment, and parts used in buildings and industrial plants deteriorates over time.
  • The Insulation Resistance test determines the entire resistance among any two points segregated by electrical insulation.
Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Continue Reading

What is a Jet Pump? – Principle, Types, Comparison
Modbus Relative Addressing
International Standards – Types and Their Details
What is a Load Cell ?
List of Tools used by Instrument Technician or Engineer
The Aghorn Hydrogen Sulfide Accident – H2S Gas
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
1 Comment
  • Nimal Rathnaweera says:
    April 9, 2023 at 9:24 am

    What is the minimum value for the insulation resistance in a domestic electric installation?

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
210kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

Look Listen Feel of Instruments – Instrumentation Engineer Maintenance
Difference Between CNC Machine and VMC Machine
What’s the Best GPS Fleet Tracking Software and Systems?
Why do Teenagers want to be Entrepreneurs?
Slip Rings in Robotics – Types, Applications, Advantages
What Can You Do with an Engineering Degree?
Loop diagram and System Inspection Lab Exercise
9 Best E-Book Apps for Students

Keep Learning

Technology is Shaping the Future of Education

How Technology is Shaping the Future of Education?

Introduction of Urea Bagging machine

Introduction to Urea Bagging Machine

HVAC System

What is HVAC System?

Types of Engineering Courses

Various Types of Engineering Courses

Instrument Skid

What is an Instrument Skid? – Example of Metering Skid

importance-of-device-diagnostics

Importance of Device Diagnostics

Overview of Resistor

The Information About Resistor Color Code You Should Know

Digital Instrument Example

Digital Measuring Instruments – Types, Functions, Advantages, Disadvantages

Learn More

Nameplate Markings

Explosive Atmospheres & Hazardous Classification

Motor Disconnector Switch

What is a Motor Disconnector Switch? – Purpose, Principle, Factors

Why is White Powder Used in Electrical Cables

Why is White Powder Used in Electrical Cables?

Difference Between Modbus TCP IP and Profinet

Difference Between Modbus TCP IP and Profinet

DCS Vs PLC

Difference between DCS & PLC Systems

Diaphragm seal for pressure measurement device

When to use a Diaphragm Seal?

Stepper Motor Parts

Stepper Motor MCQ

Calibration Procedure of displacer type Level transmitter

Calibration of Displacer Level Transmitter

Menu

  • About
  • Privacy Policy
  • Copyright

Quick Links

  • Learn PLC
  • Helping Hand
  • Part Time Job

YouTube Subscribe

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?