Production Safety Testing Ensures Compliance with Global Safety Standards

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Because virtually all electronic devices and electrical apparatus require safety certification, manufacturers must submit samples of their products to compliance agencies and regulatory authorities to ensure they meet global standards. 

This article gives an overview of the many safety standards required for certification and how advanced hipot testers have evolved to speed and simplify the compliance process. It also discusses the critical pre-testing setup and safety procedures required to ensure user safety. Finally, it describes the four types of essential hipot tests, dialectic withstand, insulation resistance, ground continuity, and ground bond testing, conducted during final production as well as the test results to look for.

Understanding Global Safety Standards

During the production phase of product development, products destined for sale in the U.S. market are typically sent to Nationally Recognized Testing Laboratories (NRTLs) for compliance testing. NRTLs provide services to certify compliance with the relevant standard(s) and regularly inspect the testing equipment and facilities.

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The compliance evaluation conducted by an NRTL typically investigates two key areas of a product, as follows: 

1. Construction'Mechanical construction, spacing, clearances, etc.; and

2. Safety'To assure safe operation, even under high-stress conditions.

    

The details of what constitutes an NRTL-certified product depend on the specific standard (or standards) applicable to that product. For products that will be sold and used in jurisdictions outside the U.S., the requirements of different standards may be applicable, potentially complicating the process of achieving global access. 

In an effort to address this challenge, efforts are ongoing to harmonize standards internationally. An example is IEC -5-1, a standard developed by the International Electrotechnical Commission (IEC) that addresses the safety aspects related to electrical, thermal, and energy in adjustable speed electrical power drive systems. In the U.S., the requirements of IEC -5-1 have effectively replaced those of UL 508C, which has been withdrawn and superseded by UL -5-1. 

The Evolution of Hipot Testing

Hipot testing has long been a standard procedure for various types of equipment. Hipot testers get their name from the 'high potential' (high voltage) that they produce in order to perform dielectric withstand and insulation resistance tests. Many hipot testers also provide accurate, low-resistance measurements and low-resistance/high-current outputs to test ground resistance and ground bond integrity. 

The early commercial hipot tester was not much more than a step-up transformer used to adjust an applied voltage in stepped increases over prescribed time segments to test for leakage or component breakdown. However, this legacy method could easily lead to incorrect results when leakage current causes the voltage output from a high-impedance transformer source to drop. 

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In contrast, today's most advanced hipot testers utilize electronic source technology to assure compliance with IEC-, which explicitly requires that 'the voltage test equipment shall be able to maintain the required voltage for the specified period of time.' 

Hipot Testing Setup and Safety Procedures

By its very nature, electrical safety testing involves the use of high voltages and requires test operators to follow strict adherence to safety procedures. Operators should understand that high voltages are dangerous and that care must be taken to avoid contact with energized circuits. The importance of having trained personnel as the first step in ensuring a safe testing environment can't be overstated. 

Station Setup

The next step is determining where the test station will be located. The test area should be isolated from the factory assembly area and located away from routine foot traffic to help ensure the safety of those who occasionally come near the test station. In addition, operator distractions should be kept to a minimum and the area should be conspicuously marked with internationally approved signage, such as 'DANGER ' HIGH VOLTAGE.' 

During testing, the hipot tester itself should have indicator lights to denote when high voltage is present. There should be ample and reliable power supplied to the test station. Verify that the power wiring meets electrical code requirements for polarization and grounding. Always use an outlet that has a properly connected protection ground and make sure this ground has been tested to ensure a low impedance path to the panel ground and earth bonded ground. 

Figure 2a/2b illustrates two alternative approaches to the setup of a benchtop hipot test. In Figure 2a, the operator is wearing safety glasses, and the device under test (DUT) is placed on the test bench equipped with a combination of palm switches and a footswitch to prevent the operator from making direct contact with the DUT while testing is underway. As a practical matter, the use of palm switches is typically restricted to short-duration tests done on a repetitive basis with a series of DUTs. If this test setup is used for longer tests, operators often find a way to bypass the palm switches, thereby defeating their intended purpose of protecting the operator.

Figure 2b shows the DUT placed under a protective cover with an interlock to isolate the operator during the test. The use of an enclosure is a more reliable means of assuring operator safety, particularly when testing requires longer time periods. More elaborate test stations can include a hipot tester interlock as well.

One safety method that utilizes the interlock is a light curtain, which is an infrared light beam that opens the interlock if anyone interrupts any part of the beam. The output of the light curtain is connected to the interlock terminal on the hipot tester. If the interlock is open, high voltage is immediately terminated. The light curtain is placed in between the hipot tester or the DUT and the operator. For the operator to touch the high voltage, they would have to pass through the light curtain, triggering the opening of the interlock and terminating the high voltage. 

If the hipot is placed behind a light curtain, a method must be available to initiate the test, and a footswitch is an easy solution. But keep in mind that the test space must be designed to prevent anyone from reaching the high voltage by going around the light curtain.

Operator injury may result if the hipot tester is not properly connected to an earth ground. The work area and bench surface should consist of non-metallic materials, which means that metalwork surfaces should be avoided, and metal objects should not be placed between the operator and the DUT. All other metal objects should either be grounded or placed outside of the test area altogether. An ESD mat is not a recommended platform for a test station, as it may cause erroneous readings for leakage and is unnecessary in this application. 

The test equipment should also provide for immediate and safe removal of the output voltage using internal discharge circuity, either at the conclusion of the test or if the test is interrupted. Never remove power for the hipot tester. If there is a power interruption, use extreme care in any contact with the DUT. The safest approach is to leave the DUT connected to the hipot tester until power is restored and the tester can conduct its discharge function.

The test station should have sufficient space for the tester and the DUT without the operator having to reach over the DUT to access the tester. The tester should be at least three inches away from the wall to provide proper airflow for the unit. Ideally, the DUT should be isolated from the operator and the tester. For larger DUTs, which are wheeled to the test station, the cart should be non-conductive and have locking wheels. (This also applies if the tester needs to be wheeled to the DUT.) Keep the area clean and neat, and arrange the equipment so that it is easy and safe for the operator to use. 

There are many safety features that can be added to the test station to prevent the operator from encountering high voltage, such as guards or enclosures. When placed around a DUT, guards or enclosures should be non-conducting and be equipped with safety interlocks that interrupt all high voltages when open. Interlocks should be arranged so that operators are never exposed to high voltages under any conditions. 

In addition, it is easy to implement circuit palm switches that prevent the operator from encountering high voltage during testing. The basic operation of a palm switch requires the operator to use both hands to initiate a test with, potentially, a footswitch to activate the test. If one or both hands are removed from the switches while testing, the test is immediately stopped. The switches are placed directly in front of the operator and spaced shoulder-width apart. Spacing the switches in this way prevents an operator from trying to press both buttons down with one hand or object. 

No high voltage can be applied to the output terminals and DUT until both switches are pressed simultaneously. The operator cannot touch the DUT or test leads if both hands are on the palm switches. The palm switches are connected to the digital I/O on the hipot tester. Only when the switches are in the down position is the start function enabled. Once one switch goes up, the safety interlock is enabled, terminating the output voltage of the hipot test. This method is safe, quick, and effective.

On a regular basis, typically at the start of every shift, the tester itself should be checked by connecting the tester to both PASS and FAIL samples. These samples should be designed to confirm the proper operation of the tester based on the type(s) of tests to be conducted (hipot, insulation resistance, ground resistance, or ground bond). Once all of the connections are made, and the prescribed test procedure is selected, the operator should confirm that all test parameters specified in the testing documentation are displayed on the tester screen. Operation of the test can then be conducted, keeping in mind the safety considerations described previously.

Hipot Testing During Production

Hipot testing during production is performed to:

• Assure compliance with safety agency labeling requirements;

• Detect defective components or assembly flaws; and

• Reduce the incidence of latent field failures and the attendant warranty costs.

   

Once in production, products must be 100% tested to confirm compliance with the related agency certifications and safety standards. Production tests are less stringent than initial certification testing but will generally include basic dielectric withstand and shock hazard (leakage) tests. 

Plug-connected devices will also be subjected to ground resistance and ground bond tests if required by the applicable standard. Electrical motors, transformers, and other such devices will likely include insulation resistance tests. 

Periodic inspection and calibration of test equipment is a standard requirement to maintain NRTL certification for the product being produced. This inspection will include a check of hipot instrument calibration certification. This 'cal cert' is typically required to be renewed on an annual basis. (NRTLs require compliance certification with ISO .) Another common requirement prescribed by most NRTLs is a daily functional test of the hipot equipment.

Test 1: Dielectric Withstand

The basic hipot test applies a high voltage from the conductors to the chassis of the DUT. This test is often referred to as dielectric test or voltage withstand test. Its purpose is to confirm that the insulation and isolation of the non-conducting surfaces from the operating voltage are sufficient to avoid a shock hazard. The typical specification for this test is V + 2x normal operating voltage. 

Both AC and DC hipot tests are possible and, in general, the test should use the same type of voltage as would be used during normal operation. However, if a DC hipot test is used on an AC circuit, the hipot voltage should be two times the peak, that is (2 x 1.4 x RMS) + V (see Figure 3). 

Depending on the applicable standard, units will pass this test if either: 

• • The leakage current measured is less than the maximum allowable current; or

• No breakdown occurs, i.e., there is no sudden and uncontrolled flow of current.

In the case of double-insulated products, higher voltages are often specified in the test standard. In addition, this class of device typically requires special fixturing to connect the non-conductive outer shell to a conductive element.

Defects that are often detected with the hipot test include contamination (e.g., dirt, debris, etc.) and lack of proper spacing (creepage and clearance) of components. Creepage is measured across surfaces, while clearance is the air gap between components. Contamination would likely cause an unacceptable level of leakage current. Clearance problems can result in a breakdown.

Desirable hipot tester features for dielectric withstand testing include:

• Adjustable maximum output voltage:

  • 5KV is adequate for many applications

  • Higher voltages (up to 30KV) may be required

  • AC and DC outputs

  • Excellent regulation ' both line and load

  • Controllable ramp rates, dwell times, and discharge features

  • Phase angle measurement of leakage current ' capacitive coupling detection

     

  • Some standards allow for in-phase and quadrature currents to be measured separately. Leakage current due to capacitive coupling may not be a safety concern

• Min/max pass/fail current limits:

   

  • Separate limits during ramp

• Programmable multichannel testing

Test 2: Insulation Resistance

Insulation resistance testing is likely to be required in motor winding, transformer winding, and other applications involving cabling or insulated wire. Insulation resistance testing typically involves confirming that the resistance exceeds a defined high resistance value. 

In many instances, insulation resistance needs to be measured between several conductors. Examples include cable/connector assemblies, multiconductor cables, and relays. To make this measurement, all the conductors except one are shorted together, and the test voltage is applied from the remaining conductor across the bundled ones. Each wire is then tested in this fashion (see Figure 4.)

Desirable hipot tester features for insulation resistance testing include:

• Wide range of selectable test voltages

• Accurate/repeatable high-resistance measurement

• Programmable high voltage switching accessory

• Multichannel programmable testing

• Pass on steady and increasing voltage

Test 3: Ground Continuity

Ground continuity testing is performed to confirm that the conductive chassis of a device is safely connected to the earth ground pin on the power plug. This assures protection against shock hazards even if the equipment suffers an internal short to the chassis. The current would be shunted via the ground wire and would likely trip the breaker or blow the fuse. 

Ground continuity is performed by applying a low current (e.g., 50 mA) and calculating the resistance from the ground pin on the power plug to selected locations on the exposed surfaces of the DUT. 

Desirable hipot tester features for ground continuity testing include:

• Accurate, repeatable low resistance meter

• Plug adaptor accessory to speed testing

   

Test 4: Ground Bond

Whereas ground continuity measures the resistance of the safety ground connection, the ground bond test assures the integrity of the connection. Using the same test setup, a high current is passed through the circuit. If the ground bond is solid, the current passes without a change in resistance. 

Desirable hipot tester features for ground bond testing include:

• Accurate high-current source

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• Programmable test currents and test times

• Plug adaptor accessory to speed testing

• 4-wire milliohm meter ' providing a Kelvin connection for highly accurate low resistance measurement

Conclusion

Hipot testing is an important final step in the production process for most electrical and electronic equipment. With programmable features and advanced functionality, today's hipot testers simplify electrical safety testing. But before commencing testing, manufacturers should be aware of the many updated safety certification standards and their requirements. And test operators must ensure upfront that they have set up a safe testing environment and fully understand the applicable testing protocols. 

Hipot testing gets its name from the 'high potential' that they generate in order to perform 

• Dielectric withstand and 
• Insulation resistance tests. 

As a result, this testing remains a common procedure for various types of equipment. 

Many hipot testers also provide exact, low-resistance, high-current outputs as well as low-resistance measurements for measuring ground bond integrity and ground resistance. 

Most modern hipot testers are currently employing electronic source technologies to ensure compliance with IEC-, which clearly states that the voltage test equipment must be able to perform in maintaining the required voltage for a specific time period. 

This post provides an overview of Hipot Testing.

What is Hipot Testing?

• Transformers, 
• Relays, 
• Switchgear, 
• Bus-bar, 
• Generators, 
• Cables, 
• Lightning arresters, and many more.

This test can be done on devices ranging in voltage from very low to very high. 

The hipot test is extremely useful for finding terminal spacing difficulties, faulty cable junctions and terminations, crushed insulation, reduction in inside clearance and creepage, corrosive/conductive impurities, and braided shielding (or) stray wire stands.

Importance of Hipot Test

The relevance of the Hipot test is that it basically evaluates the electrical insulation range for the specific device. 

This test simply determines whether or not the insulation can withstand transient overvoltages. 

This might be done for a wide range of devices over a set period of time. This test is also beneficial in identifying problems with the insulation, which is typically finished with braided shielding, such as cuts, stray wire strands, tolerance mistakes, terminal spacing issues, corrosive impurities, and so on. 

Many faults that occur during manufacturing, such as creepage or incorrect clearance distances, can be detected with this testing. 

A Hipot test is required to measure the strain of an electronic component for security and quality assurance objectives.

Why Hipot Testing is Important?

The Hipot test is significant because it determines the level of the electrical insulation of a certain device or assembly. Technicians employ testing to determine whether the insulation can withstand transient overvoltages ' the 'push' that triggers electromotive charges to move in a wire (or) other electrical conductor. 

The electrical insulation is subjected to high voltage for an extended period of time to ensure that it meets safety & quality standards.

The Hipot test identifies insulation defects by identifying the electrical insulation to the transient overvoltages. 

It is essential to look for these problems. Insulation is frequently subjected to unexpected surroundings (or) circumstances that can impair device performance. 

Electrical insulation to the electronic harnesses & cable assemblies can be compromised by 

• Braided shielding, 
• Stray wire strands,
• Tolerance mistakes, 
• Corrosive pollutants, and 
• Terminal spacing problems. 

It can also be used to locate cuts in the insulation, as well as nicked or crushed insulation.

Hipot testing may also be carried out on manufacturing lines while the product is being manufactured. 

How Hipot Tests Work?

To ensure the safety and quality of an electronic equipment, a Hipot test is required. It ensures that no breakdown or perforation occurs at high voltage & that insulation distances on transmission line as well as the air are observed. Tests can be carried out between mutually insulated components of a part or between electrified parts & electrical ground. While testing, electric current will flows between two different locations in either case.

The test duration must be closely related to the device's safety regulations. For products specified by IEC , the international standard for the rated voltage, it should be one minute. Otherwise, current limit might be regulated to fulfill the assembly's safety standards.

Hipot Testing Procedure

The Hipot Testing step-by-step procedure is described in detail below.

Step 1: First, open switches/CBs to disconnect the DUT from both ends.

Step 2: A discharge rod is subsequently utilized to discharge all of the conductors.

Step 3: Set CAUTION labels (or) Barricades near the HV testing area.

Step 4: Connect Hipot's Master Earthing Terminal (MET) to the proper System Earthing.

Step 5: Connect the operational earthing terminal to the body earth (or) safety ground.

Step 6: Confirm that the connection is correct.

Step 7: Connect the kit's HV terminal to the conductive portion of the test object.

Step 8: Verify all circuit phase conductors by connecting each phase to ground according to the time, current, & voltage settings that is pre-determined.

When all of these procedures have been completed, the following points must be verified.

The current flow would be measured as a result of the voltage difference between the conductors. There must be no breakdown of either the solid (or) air insulation. In addition, the current flow should not exceed the 5mA peak. In order to pass the test, the test object must be subjected to the minimum amount of stress at the predetermined voltage for 1 minute without showing signs of breakdown. Hipot testing can thus ensure the security, excellence, & consistency of essential electrical equipment.

Cable Hipot Testing

A Hipot test for the cable is used to determine whether (or) not a power cable is in good condition. This test is carried out with the help of a Hipot Test kit, which comprises 

• Auto transformer,  
• Test transformer, 
• Some necessary components, &
• Power cord.

Cable Hipot Testing Procedure

The cable hipot testing step-by-step procedure is described in detail below.

Step 1: To get started, the power wire being checked is entirely isolated from the both ends. The cable's 3 phases are discharged with the support of earth rods, allowing the cable to work safely.

Step 2: A control box supplies 220V AC power to the Autotransformer, and the output can be utilized to control the input voltage to the transformer's main windings. 

Step 3: The test transformer is employed here to increase the voltage to the required test range.

Step 4: If the testing type is AC Hipot testing, the test transformer's secondary winding terminal is connected to the cable's phase conductor. 

Step 5: If the testing is DC Hipot, the silicon rectifying diode may be simply connected in series with the test transformer's secondary winding. 

Step 6: The secondary terminal of the test transformer is linked to the cable's phase conductor via the diode, while the other terminal is routed straight to earth via the cable armor.

Step 7: Insulation between the phase conductor and the ground is evaluated. Once the power cable is in operation and charged, simply connect the cable's armor to GND and the armor will be at '0' potential.

Step 8: As a result, insulation between phase conductor and armor is tested. So, the input voltage of 220 volts is raised to the required test voltage, which ranges from 6 KV to 60 KV, and the Hipot test is done. The test voltage is increased in accordance with the voltage and insulation level of the component to be tested.

A similar procedure is followed for the remaining two phases of the power cable. We might test their physical condition of the insulation between phase and earth in this method. To assess the condition of the insulation between two phases, connect one high voltage lead to one phase and the other to another phase and ground.

In a similar way the hipot test for transformers is primarily used to determine if a resistance welding transformer is electrically stable enough to be used in production. 

This type of test is quite quick and simple to execute in 5 minutes after disconnecting from the main power and the secondary power. 

This test determines whether there is an internal short, which is usually caused by an insulation breakdown, or whether there is an open circuit in the secondary.

Formula for Hipot Testing

The Hipot test voltage is calculated using the formula below. 

Hipot voltages are mostly used to test the insulation and ensure that there will be no electrical breakdown.

A basic thumb rule for measuring the hi-pot test voltage is twice the working voltage + V.

Hipot Test Formula = 2 x (Working Voltage) + V

Ex: 

If the operating voltage is 120V,

2 x 120 + = V.

In general, the hipot test can be described as AC/DC. As a result, the following formula is typically used to equalize these hi-pot tests.

VDC = VAC (PEAK) = VAC(RMS) × '2

The hi-pot test period is generally 1 minute, however according to safety standards, 1 to 2 seconds are allowed for testing the manufacturing line only when the voltage increases by 20% over the 1-minute test.

What is a Hipot Test used for?

The high potential (hipot) test measures the insulation's dielectric strength to ground. The hipot test determines the possibility that the ground wall can withstand an overvoltage event. An over-voltage is defined as a voltage greater than the device under test's (DUT's) highest functioning (line-to-line) voltage.

What is a Hipot Tester?

Safety Guidelines in Hipot Test

When working on an electrical instrument, the output is potentially dangerous voltages and currents, so it is important to check that device on a regular basis and recommend secure testing methods such as setting up a secure work area, properly training test operators, and setting up safe test procedures.

Knowing and detecting safety problems so assist a manufacturer in securing their workplace. 

The primary safety considerations when doing the Hipot test are outlined below.

• Keep unauthorized workers out of the testing area.
• Arrange the test station in a safe and orderly manner.
• Make no unauthorized adjustments to the test equipment.
• Verify any custom test setups and record the appropriate ratings.
• During a Hipot test, never touch the connectors or the product.
• When there is a problem, first turn OFF the high voltage.
• Before switching connections, discharge any tested equipment correctly through DC supply.

Advantages of Hipot Test 

• This test protects operators from electrical shock injuries.
• It lowers the cost of replacement or repair.
• It reduces the risk of motor vehicle injury.
• It extends the equipment's life.
• This test assists manufacturers in determining corrosion and damaged insulation.
• This test often includes either high potential or high voltage testing.
• The key advantage of this test is its adaptability.
• This test detects material and workmanship faults, insulation weak points, conductor gap spacing, dirt, pollutants, and moisture within the insulation. 

Disadvantages of Hipot Test

• It just measures total leakage current.
• Because it measures the total leakage current, a large Hipot transformer is required.
• It is not usually accepted by safety departments.
• The DC hipot test is more expensive than the AC hipot test.

Application of Hipot Test

• Ensure the insulating integrity of power transmission cables.
• The insulation between the windings and the earth is being tested.
• Checking the insulation of appliances, PCBs, & other electrical components.
• Electrical systems can benefit from preventative maintenance.
• Motors, transformers, and high-voltage systems are examples of industrial equipment.
• Manufacturing of electrical appliances
• Aerospace and defense technology

What is a Dielectric Tester?

A dielectric withstand test (or) pressure test (or) hipot test in electrical engineering is an electrical safety test done on a component or product to verify the effectiveness of its insulation. The test could be performed between mutually isolated sections of the part, (or) between powered parts and ground.

A Dielectric Strength Tester (also known as a hipot tester or dielectric strength tester or flash tester, or high voltage tester) is then used to determine this current.

Difference between AC and DC Hipot Test

AC Hipot Test vs DC Hipot Test

AC Hipot TestDC Hipot TestAC hipot testing is as simple as applying a higher AC voltage to the test conductor and measuring leakage current.DC hipot is used to determine the insulation resistance of a cable by simply increasing the voltage on the test instrument.AC hipot test equipment's are huge and heavy.DC highpot test supplies are compact and light.The AC hipot test employs a lower voltage.Higher voltage is used in the DC hipot test.This test makes use of alternating current (AC) voltage.This test makes use of direct current (DC) voltage.The AC hipot test has a higher o/p current capability.This test has a very low o/p current capability.This test only measures total current and does not provide a precise assessment of leakage current.By just reading actual current, this test provides a more exact leakage current reading.This test is effective in both positive and negative voltage polarities.Since it charges only insulation inside a single polarity, this test does not do polarity-based testing.It is not economical.It is inexpensive.This cannot be used to make a diagnostic test.When compared to other past test findings, this can be used as a diagnostic test.It is not widely accepted by security agencies.It is widely accepted by security agencies.

How to do DC Hipot Testing?

The iTIG hipot tester (or) motor analyzer applies DC voltage to open (disconnected) windings. Depending on the test method employed, the DC voltage potential in windings is instantly increased to a predefined level or gradually increased to this level.

What is Very Low Frequency (VLF) Testing?

A direct correlation exists between the test frequency and the amount of electricity needed to activate the capacitance of a device. Power consumption during energization utilizing a VLF power source is 500 to 5,000 times lower (0.1 ' 1Hz) than that of 50Hz.

Therefore, for hi-pot testing (or) offline partial discharge (PD) testing of cables, VLF testing is the more practical selection.

Given the high voltage but low power aspect of a 50Hz power supply, it is common practice to disconnect cables & voltage transformers before testing starts to compensate for their inherent capacitance. A VLF power supply will be used to test lengthy busbars or connected switchgear.

HiPot Operator Checklist: Basic Safety Principles and Procedures

• Only fully trained operators must be permitted to operate the equipment and enter the testing area.
• Make no connections to a DUT until you have confirmed that the high voltage (HV) warning light is turned OFF.
• Never come into contact with a DUT, the tester, or the test leads.
• Always attach the ground clip initially when connecting the leads to the DUT.
• Never directly touch the metal of the high voltage probe (or) HV test lead. Only contact the insulated areas while there is no high voltage present.
• Only utilize interlocked test fixtures when possible.
• Before starting a test, double-check all DUT connections. Make ensure that no other things are in the vicinity of the DUT (or) the tester.
• Maintain a clean and uncluttered environment, and prevent crossing test leads.
• To reduce capacitive coupling, suspend the test leads.
• Follow the instructions for each test accurately as printed.
• Before starting a test, double-check all setup parameters and inspect all leads for the signs of wear.
• Using a performance verification device, ensure that the tester is working properly. This will additionally confirm the test leads' condition. Maintain a regularly scheduled calibration cycle for the equipment.
• When performing a DC test, keep a 'hot stick' nearby and utilize it to discharge any connection (or) equipment that may get unplugged during the test. This is required because unexpected, harmful charges can accumulate throughout test when a connection breaks.
• When a test is over, make sure the HV light is turned off.  The discharge of electricity may take some time if the test was DC.
• Ensure that the tester & test station utilize all of the hipot tester's built-in safety features & functionalities.
• Test the memory on a regular basis to ensure uniform testing & that the setting parameters are not changed.
• Verify that the AC power supply to the tester is appropriately placed with the low impedance ground connections. Also, ensure that the emergency switch turns off all power to the tester, the DUT, and any electrical equipment & feeds in the testing area.
• In the case of a heart attack or contact with high voltage, the operator and close coworkers should be educated in compression-only CPR.

Difference between Hipot Test and Megger Test

Hipot Test Vs Megger Test

Hipot TestMegger TestThe hipot test, also known as the Dielectric Withstand Test, measures the level of electric insulation in a device by determining whether or not current can flow between two specific ends at high voltages.An electrical test called the Megger test is used to evaluate how effectively an electrical device's insulation is performing.A high potential test is another name for a hipot test.Alternative terminology for a megger test is a megohmmeter test.By applying a high voltage to the equipment is all that is needed to conduct this type of test on electrical insulation.By applying a small DC voltage to the equipment, this test verifies the electrical insulation.In order to identify insulation failures or flaws, this test uses a higher voltage.The insulating resistance is measured by applying a low DC voltage in this test.In most condition, the voltage used for this test is far higher than the standard operating voltage.In most condition, the voltage used for this test is far lower than the actual operating voltage.The high-pot test is a way to make sure that electrical insulation is enough to withstand a typical over-voltage transient.Insulation resistance is evaluated using this test.

Frequently Asked Questions (FAQ)

1). What is the formula for hipot test?

The Hipot test voltage is calculated using the formula below. 

Hipot Test Formula = 2 x (Working Voltage) + V

In general, the hipot test can be described as AC/DC. As a result, the following formula is typically used to equalize these hi-pot tests.

VDC = VAC (PEAK) = VAC(RMS) × '2

2). What is a hipot test for busbar?

In order to verify that there is adequate electrical isolation between conductors, HiPot (High Potential) testing is done. A HiPot test, for example, at a given voltage, the various conductive layers that make up a laminated bus bar are adequately isolated from one another.

3). What is hipot voltage?

A high voltage is directly applied to a device being tested in a hipot test, which is known as high potential test. To put more stress on the dielectric qualities of the device being tested, the test voltage is typically significantly higher than the typical operational voltage.

4). What causes hipot failure?

A breakdown in insulation causes a hipot failure. It is indicated by an abrupt rise in current flowing as an outcome of the test voltage being applied.

5). Why dielectric test is performed?

The dielectric test determines the breakdown voltage on the weak sections caused by the actions of any type of dielectric. This test is used to ensure that the component complies with electrical security testing standards as well as the insulation effectively protects users from current shock.

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