Guide to Electrical Safety Testing

Guide to Electrical Safety Testing
Guide to Electrical
Safety Testing
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GENERAL INFORMATION
GENERAL INFORMATION
Why Test?
There are four main reasons why you should safety test your products prior to shipment
1. Safety
Ensure that the product is not going to pose a hazard to the end user.
2. Quality
Detect workmanship defects and prevent faulty components from being installed.
3. Cost Control
Identify production problems before a product is shipped, preventing costly recalls.
4. Liability
Prevent product liability suits because the responsibility of performing electrical safety tests
ultimately rests on the manufacturer
NRTLs (Nationally Recognized Testing Laboratories) set standards outlining tests that must be performed on a product before
it’s considered safe for the consumer market. NRTLs implement and enforce electrical safety testing to protect consumers from
a potentially fatal electric shock.
NRTL standards generally specify two separate testing categories
Type Test
• Performed as a laboratory or prototype test
• Done on sample basis
• Used to detect defects in product design
• More rigorous testing
Production Line Test
• Performed on 100% of products on the production line.
• Used to detect manufacturing or workmanship defects
As a manufacturer or test operator, it’s up to you to ensure you have the proper knowledge and
training to use high voltage equipment.
Before working with an electrical safety test station, you need to make sure you are a qualified operator according to OSHA
guidelines1.
NRTL Examples: Underwriters Laboratories (UL - United States), TUV Rheinland (Germany), Canadian Standards Association
(CSA - Canada), ETL (Intertek - United States) and CCC (China Compulsory Certification - China)
Occupational Safety and Health Administration
An agency of the United States Department of Labor charged
with ensuring safe working conditions as well as enforcing
standards and providing workplace training and education.
NRTL standards dictate that electrical products incorporate two lines of defense to protect the
user from electrical shock
Insulation
Safety Grounds
• Separates power lines from low voltage circuits.
•Separates power lines from isolated power supplies.
• Allow dangerous fault currents to return to
system ground.
•Isolates input power from the chassis or case of an
electrical device.
• Safeguards against fire.
OSHA 1910.332 Subpart S • osha.gov
Effects of the electrical current on the human body
• Enables circuit breakers to open.
Current
Reaction**
0.5 to 1 milliamp
Perception
5 milliamps
Slight shock felt, startled reaction
Electrical products can be classified according to insulation type
6 to 30 milliamps
Painful shock and inability to let go
Class I Products
• Terminate in 3 prong line cord (line, neutral and ground).
30 to 150 milliamps
Extremely painful, respiratory arrest, ventricular fibrillation, death possible
• Ground prong connects to product chassis.
10 amps
Cardiac arrest, severe burns
• Protects against damage to electrical equipment.
• Safety through basic insulation and proper grounding.
Class II Products
• Double insulated products.
• Terminate in 2 prong line cord (line and neutral).
These effects are for voltages less than 600 volts. Many electrical safety testers can output voltages in excess of 5000 volts which can cause more
severe reactions at lower current levels.
**
1
OSHA 29 CFR part 1910.332 Subpart S defines the training requirements for anyone exposed to voltages in excess of 50 volts.
• Safety through dual layer of insulation.
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OPERATOR SAFETY AND TRAINING
A Qualified Operator Must Know
OPERATOR SAFETY AND TRAINING
A Qualified Operator Must Know
Knowledge
Example
Knowledge
Example
1. D
etermine whether an exposed
conductor is energized or not.
Hipot tester with the output voltage ON. The
CAUTION and HIGH VOLTAGE warning lights
illuminate RED when the tester is active. This
indicates that the tester is in a dangerous state.
7. K
now the methods of release for
victims who are being shocked.
Methods include using a non-conductive
material (i.e. a fiberglass pole) to release
someone from a live circuit. Using an E-Stop
can also shut off power to the entire station
and release the victim.
2. D
etermine the nominal voltage
of an electrical circuit by reading
drawings, signs and labels. Know
how to use the equipment. Every
tester should come with a user’s
manual.
eview this manual prior to using the
R
Product power cord with label displaying
the nominal voltage and current of the device.
3. Understand approach distances
and corresponding voltages to
which you may be exposed.2
Slaughter testers can output up to 5000 VAC. Always review product
specifications before using the equipment.
4. You should be trained to identify
and understand the relationship
between electrical hazards and
possible injury.
Refer to the table “Effects of Current on the Human Body” on the preceding
page.
5. Know the safety features of the
equipment and utilize them.
Most Slaughter testers have an automatic discharge circuit that will discharge
the DUT in less than 200 msec after the test completes. This ensures the DUT is
safe for you to touch once the test has completed.
6. D
etermine if Personal Protective
Equipment (PPE) is necessary,
what type of PPE3 is necessary
and how the PPE is rated. OSHA
now requires in addition to being
a Qualified Person, that you must
wear PPE for protection from
shock if you cross the Restricted
Boundary.
This image contains high voltage gloves,
safety glasses, a hard hat and high voltage boots.
These are common examples of the PPE
you should wear as an operator
when using high voltage equipment.
DO NOT touch a person who is being shocked
or you could also become part of the circuit!
equipment.
Note: The restricted boundary for live parts
operating between 751 V and 15 kV is 2 feet
2 inches.
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8. U
nderstand that the tester is a
variable voltage power source that
will output current to any available
ground path. Contacting the DUT
during the test can result in a
dangerous shock hazard.
This image shows someone contacting
a live circuit. The current flows directly
through their body to ground causing
severe, possibly fatal injuries.
9. Y
ou must know the importance of
discharging the DUT.
While all Slaughter testers do have an automatic discharging circuit, lifting
the high voltage or return lead from the DUT before the test is complete can
leave the DUT charged. If the Hipot does not have a complete circuit, it cannot
discharge the DUT at the end of the test.
10. U
nderstand that each step in the
work plan must be executed as
planned.
DO NOT TAKE SHORT CUTS!
Refer to Test Station Safety Procedure Checklist to review your Hipot setup
before you test.
Scan for additional Slaughter educational material
Slaughter Whitepapers
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2
3
NFPA 70E Table 130.2(C) outlines approach boundaries to live parts for shock protection.
NFPA 70E Section 130.7(C)(10) shall be used to determine the required PPE for the task.
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OPERATOR SAFETY AND TRAINING
OPERATOR SAFETY AND TRAINING
Setting up a Safe Workstation
G
One of the best ways to prevent injury is to ensure that the test station is set up safely and
securely. Test stations can be setup with or without direct protection depending on your
requirements. Direct protection means that the operator cannot physically come into
contact with an energized DUT while a test is running.
E
E
F
E
A
F
B
10’
J
C
H
I
A
DUT Safety Enclosure
Signal Tower Light
This is wired to the Hipot tester’s Remote
Safety Interlock. This protects you from
touching the DUT while a test is in progress.
If the enclosure door is opened, the tester’s
high voltage is immediately disabled.
Gives an indication as to the status of
the testing area. A green light indicates
the Hipot tester is not outputting high
voltage and the test area is safe. A red light
indicates that the Hipot tester is active and
to stay clear of the test area.
Non-Conductive
Work Bench
Test Operator
D
High Voltage Insulation Mat
This isolates you from ground which
provides an additional means of protection
when operating high voltage equipment.
F
Emergency Stop Button
Located on the perimeter of the test area.
In the event of an emergency, someone
outside the test area can hit the E-Stop
button to immediately cut off power to the
entire test station.
G
Warning Signs
Mark the testing area with clearly posted
signs that read: DANGER - HIGH VOLTAGE
TEST AREA. AUTHORIZED PERSONNEL
ONLY.
Station without direct protection against
electric shock. Such a station does not protect
the user from touching the DUT during a test.
Reference
Only use a work bench made of nonconductive material such as plastic or
wood. This ensures no stray leakage current
could flow through you during a test.
I
Dual Remote Palm Switches
Safety Made Simple®
DUT – This large DUT prevents you from using a product safety enclosure. Instead, other precautions
must be taken to ensure a safe testing station.
B
The Hipot Tester – tester used to test the DUT.
C
Test Operator.
D
High Voltage Insulation Mat – This isolates you from ground which provides an additional means of
protection when operating high voltage equipment.
Signal Tower Light – gives an indication as to the status of the testing area. A green light indicates the
Hipot tester is not outputting high voltage and the test area is safe. A red light indicates that the Hipot
tester is active and to stay clear of the test area.
F
J
G
NEC (National Electric
Code) & NFPA (National Fire
Protection Agency
H
Stipulate that any unqualified workers
shall not come within 10' of an EXPOSED
energized circuit.
4
Description
A
E
Two hand operation switches force the
operator to place a hand on each switch
and hold them throughout the test.
The palm switches should be placed at
least 21.6" (550mm) apart to prevent the
operator from one hand activation of both
switches.
5
6
GER
DAN GE
TA
VOL D
HIGH HORISE LY
G
D
H
C
C
AUT NEL ON
ON
E
Tester used to test the DUT.
P
PERS
A
Hipot Tester
E-STO
D
10’
Station with protection against electric shock.
B
B
10’
OP
G
F
P
E-ST
H
10’
E-STO
Emergency Stop Button – An E-stop button is located on the perimeter of the test area. In the event of
an emergency, someone outside the test area can hit the E-Stop button to immediately cut off power
to the entire test station.
Warning Signs4 – Mark the testing area with clearly posted signs that read: DANGER-HIGH VOLTAGE
TEST IN PROGRESS. UNAUTHORIZED PERSONNEL KEEP AWAY.
Sectioned Off Test Area – Since the size of the DUT restricts the use of an enclosure, this test area is
sectioned off by a mesh fence to keep unauthorized personnel away from the testing station. NEC
(National Electric Code) and NFPA (National Fire Protection Agency)5 stipulate that any unqualified
workers shall not come within 10 feet of an EXPOSED energized circuit.
High Voltage signs compliant to ANSI Z535-2011
See NFPA 70E Table 130.2(C)
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OPERATOR SAFETY AND TRAINING
OPERATOR SAFETY AND TRAINING
Important Information Regarding ESD Stations
Signal Tower Lights
WARNING
Do NOT setup electrical safety testing stations and ESD (electrostatic discharge) stations
in the same area. ESD protocols are designed to protect a component or device from
static discharge (not the operator from high voltage hazards). Do NOT use anti-static
robes, benches, or floor mats during electrical safety testing. All of these items are used to
intentionally ground the test operator which can cause injury or death to a high voltage
test operator. Such stations are not designed for voltages above 250 VAC.
These status lights illuminate RED when a test is running and GREEN when the test passes or
the Hipot tester is idle. Refer to figures 1 and 2 for more information.
WHY IS THIS SAFE?
Mounted lights warn operators in the nearby area
to the status of the Hipot test and if the tester is
outputting high voltage.
Additional Methods for Test Safety
In some cases, you may not be able to use a roped off test area or DUT enclosure. When necessary, there are other methods
that you can use to protect your operators:
Insulation Mats
Dual Remote Palm Switches
High voltage insulation mats on the floor of the test area.
The operator stands on the mat while testing.
Two hand operation switches force the operator to place a hand on each
switch and hold them throughout the test. The palm switches should
be placed at least 21.6 in (550 mm) apart to prevent the operator from
one hand activation of both switches. Some switches have guards over
the top to prevent one hand actuation and do not require a minimum
distance of separation.
WHY IS THIS SAFE?
The mat isolates the operator from ground while
testing which greatly mitigates the shock hazard.
WHY IS THIS SAFE?
This does NOT allow the operator to touch the DUT
as their hands must remain on the test switches
during the test.
ALWAYS REMEMBER
• Keep the unqualified and unauthorized personnel away from the testing area. If this is not possible, the
unqualified person must be supervised by a qualified operator while they are in the test area.
• Arrange the testing area out of the way of routine activity. Designate the area clearly.
Safety Probes
• Never touch the DUT or the connections between the DUT and the tester during a test.
Use extended probes to contact the DUT during a test. A push
button on the probe extends a conductive tip for contact to the DUT.
• In the case of an emergency, or if problems arise, turn off the high voltage first.
WHY IS THIS SAFE?
This forces the operator to hold extended probes
so that they cannot touch the DUT or tester while a
test is running.
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• Properly discharge any DC-tested product before touching or handling connections.
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ELECTRICAL SAFETY TESTS - THE HIPOT TEST
ELECTRICAL SAFETY TESTS - THE HIPOT TEST
The Hipot Test (Dielectric Voltage Withstand)
General Hipot Test Considerations
The Hipot test is the most common type of safety test. This test is designed to stress a product’s insulation beyond what it
would encounter during normal use. The reasoning behind this test is that if the insulation can withstand high voltage for
short period of time, it will be safe to use at nominal voltage throughout its useful life.
Voltage
6
One of the main advantages of the Hipot test is its versatility. In addition to measuring leakage currents and detecting
breakdowns, you can also use it to detect:
• Material and workmanship defects.
• Weak points in the insulation.
• Small gap spacing between conductors. Air is just an insulator and Hipot voltage will “jump” through
the air across gaps that are too small.
• Condensation, dirt and contaminants in the insulation.
When running a Hipot test, high voltage is applied to the mains conductors (LINE and NEUTRAL). The Hipot return point is
connected to the bare metal chassis of the fan. You’re essentially creating a capacitor, where the product insulation is the
dielectric material. The Hipot tester measures the resulting leakage current flowing through the insulation (represented as
capacitors between mains and ground).
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Hipot test voltage values will vary between products due to the nature of the insulation barrier. However, a good rule of thumb
that most safety agencies use to determine the appropriate test voltage for an electrical product:
(Hipot Test Voltage) = (Nominal Input Voltage) * 2 + 1000 V
For example, if the nominal voltage on a fan is 120 VAC, the test voltage would be 1240 VAC.
Not sure about Hipot test voltage? When in doubt, you should always refer back to the appropriate NRTL standard.
Test Time
Hipot test time (dwell time) can also vary between agency standards. The most common test durations are 1 sec for
production tests and 1 minute for design tests. However, if the test time is reduced from 1 min to 1 sec, the Hipot test voltage
generally needs to be raised by 20% since the insulation is being stressed for a shorter period of time.
The example below is from UL 1598 – Luminaries, outlining the voltage and time differences for a type and production line test.
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POWER
POWER
UL 1598 - Dielectric Voltage-Withstand Test for incandescent type luminaries
CURRENT
GND
CAUTION
5KVAC MAX.
6KVDC MAX.
POWER
H.V.
RETURN
EXIT
SET
Test Time
Test Voltage
60 sec (type)
1000 VAC
1 sec (production
1200 VAC
ACW / DCW / IR / GB TESTER
Leakage Current and Dielectric Breakdown
Any electrical device will produce small levels of leakage current due to the voltages and internal capacitance present within
the product. Under normal circumstances this leakage current isn’t large enough to be perceived by the human body. Yet due
to design flaws or manufacturing defects the insulation in a product can break down, resulting in excessive leakage current
flow. This is exactly what a Hipot test is designed to check.
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POWER
POWER
Current Limit
Most safety agencies do not specify leakage current limits. Here is valid method for determining proper leakage limit settings:
1. Perform a Hipot test on a sample of known good products. Record the leakage current results.
2. Calculate an average leakage current value from these samples.
3. Multiply the average value by 25%. Add this number to the average value.
This is your leakage current high limit.
4. Perform the same step, but now subtract 25% from the average value. This is your leakage current
low limit.
CURRENT
GND
CAUTION
5KVAC MAX.
6KVDC MAX.
POWER
H.V.
RETURN
EXIT
SET
ACW / DCW / IR / GB TESTER
Dielectric breakdown is defined as the failure of insulation to prevent the flow of current. The best indication of dielectric
breakdown is a leakage current measurement significantly higher than the nominal current measurement. The maximum
leakage current is dependent upon the test voltage; therefore, the leakage current will vary depending upon the product
being tested.
6
“Hipot” comes from the combination of “High Potential”
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ELECTRICAL SAFETY TESTS - THE HIPOT TEST
ELECTRICAL SAFETY TESTS - THE GROUND CONTINUITY/GROUND BOND TEST
AC vs. DC Hipot Tests
Ground Continuity Test
AC and DC Hipot tests have advantages and disadvantages that become evident depending on the characteristics of the DUT.
The table below lists the advantages and disadvantages of each type of test.
The Ground Continuity test often are required to be performed along with or prior to the Hipot test. Its purpose is to ensure
that the DUT’s safety ground connections have been made properly. This test checks for a connection between the third
prong on a line cord (Class I product) and the product chassis or case.
AC Hipot
DC Hipot
Advantages
Advantages
• Slow ramping of the test voltage isn’t necessary due to
the changing polarity of the applied waveform.
• The test can be performed at a much lower current level, saving
power and with less risk to the test operator.
• It is unnecessary to discharge the DUT after AC testing.
• Leakage current measurement is a more accurate
representation of the real current. This is due to the insulation
capacitance charging after the ramp up cycle.
• AC testing stresses the insulation alternately in both
polarities. This makes it a more stringent Hipot test.
• DC testing is the only option for some circuit components such
as diodes and larger capacitance values.
Ground Bond Test
The Ground Bond test determines whether the safety ground connection of a DUT can adequately handle the fault current
resulting from insulation failure. By simulating a failure condition and circulating excessive current through the DUT’s ground
connection, the Ground Bond test helps to verify the integrity of the connection to earth ground. This means that potentially
lethal fault current will flow to ground and not to a person that comes into contact with the DUT’s metal enclosure.
Ground Bond Tester
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DUT
Line
4320
POWER
POWER
CURRENT
CAUTION
5KVAC MAX.
6KVDC MAX.
Disadvantages
Disadvantages
POWER
H.V.
L
N
CAUTION
HIGH VOLTAGE
ACW / DCW / IR / GB TESTER
• Measures only the total leakage current (from capacitive
and resistive elements).
RETURN
EXIT
SET
5KVAC MAX.
6KVDC MAX.
High Current Transformer
Return
• Must ramp up the test voltage so inrush leakage does not
exceed Hipot tester’s capability.
• Requires a large Hipot transformer due to measuring the • Must discharge the DUT at the end of the test.
total leakage current.
•O
nly stresses insulation in one polarity. Not as stressful of a
Hipot test.
• Not always accepted by safety agencies.
A Note on Procedural Differences
Since a Hipot test is stressing the insulation of a DUT with high voltage, the applied test voltage must be the same value
whether it is AC or DC.
(Hipot Test Voltage) = (Nominal Input Voltage) * 2 + 1000 V
For a DC test use the following formula to assure that the DC voltage is the same value as the peak of the AC waveform:
DC Hipot Test Voltage = (AC Hipot Test Voltage) * 1.414
Not sure about Hipot test voltage? Always refer to the appropriate agency standard they may specify a different
multiplier for the AC to DC hipot test voltage conversion.
Low impedance
path to ground
During a Ground Bond test, high current flows from the ground pin of the DUT to the RETURN on the chassis. The Ground
Bond tester then displays the resulting ground circuit resistance.
Ground Bond/Ground Continuity Test Considerations
Current and Voltage Drop
Testing a ground circuit with a ground bond or continuity test involves running current through the circuit and measuring the
resulting voltage drop. Since all products have different current ratings, the current and voltage drop for the test will also vary.
A general range for each value is specified across NRTL standards.
General Ground Bond/Ground Continuity test parameter values
Test Parameter
Value
Current
1.5 - 2.5 X tester current rating*
Voltage Drop
4 V - 12 V
*May also indicate extra condition of current = 25 - 40 A. It depends upon which value is higher (the calculated value or 25 - 40 A value).
This is illustrated in standards such as UL 60335-1 for household appliances. It stipulates a type test for ground bond:
Test Current = 1.5 X Rated Current for appliance OR 25 A passed between ground
pin and product case, whichever value is higher. The voltage drop across the
circuit is not to exceed 12 V.
For example, if my product has a rated current of 10 A, you would test the product at 25 A as 1.5 X 10 A = 15 A.
Not sure about the Ground Bond current or Voltage Drop values? When in doubt, you should always refer back to
the appropriate NRTL standard.
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ELECTRICAL SAFETY TESTS - THE GROUND CONTINUITY/GROUND BOND TEST
Test Time
The testing time for a ground bond and ground continuity test is left to the discretion of the manufacturer. Some standards do
indicate a ground bond test time of 120 sec but most stipulate to run the test for the amount of time necessary to get a stable
reading. If you’re running a higher current test (10 A or greater), it is recommended to run the test for at least 5-10 sec. If you’re
running a low amperage ground continuity test, 1 sec is enough time to obtain a reading.
Resistance Limits
The idea behind a ground bond/ground continuity test is to measure the resistance to ground to ensure the value is low
enough so fault current will flow. The majority of NRTL standards give a range of maximum resistance values depending upon
the nature of the product’s ground wire or power cord.
Ground Bond/Ground Continuity test resistance limits
Cord Type
Resistance Limit
Detachable power cord
0.1 Ω
Permanently connected power cord
0.2 Ω
ELECTRICAL SAFETY TESTS - THE GROUND CONTINUITY/GROUND BOND TEST
Ground Bond vs. Continuity
Ground Continuity
Ground Bond
• Verifies the existence of a ground connection.
• Verifies the integrity of a ground connection.
• Readings generally given in Ωs.
• Readings generally given in mΩ
• The test is quick to set up and easy to perform.
• Provides more valuable safety information about DUT
• Usually used as an extra feature during the Hipot test.
• Can be combined with a Hipot test for a more
complete safety testing system.
The Ground Continuity test does have limitations when it comes to testing the integrity of the ground conductor. Take the
example of a line cord that has a 64 strand braided ground conductor wire . What if all of the strands were broken except for one?
A Ground Continuity test could pass a product that has only 1 strand of wire connecting its chassis to ground.
Check your NRTL standards! It’s important to remember that these values can vary from standard to standard.
As a manufacturer, it’s up to you to check your standard to ensure proper testing parameters.
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If a fault were to occur, this connection wouldn’t be capable of handling the input current to the product and could create an
open ground condition. A ground bond test would fail this test because the single wire would not be able to handle the high
current and would burn up.
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For this reason, many electrical product manufacturers have been turning to the Ground Bond test as a more thorough
alternative to the Ground Continuity test.
Not sure whether you need Ground Continuity or Ground Bond? We’re here to help! Call our technical support line
+1-800-504-0055
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ELECTRICAL SAFETY TESTS - THE INSULATION RESISTANCE TEST
TEST APPLICATION EXAMPLES
The Insulation Resistance Test
UL/IEC 60335-1: Household Electric Appliances
The Insulation Resistance (IR) test is used to provide a quantifiable value for the resistance of a product’s insulation. The tester
applies a DC voltage across the insulation of a product and measures the corresponding leakage current in order to calculate a
resistance value.
A fan needs to be tested on the production line per the UL/IEC 60335-1 standard. The fan runs from a 120 V and is a Class I
product (3 prong cord with basic insulation).
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4320
POWER
60335 Production Line Test Parameters
POWER
Test Type
CURRENT
CAUTION
Parameters
5KVAC MAX.
6KVDC MAX.
POWER
H.V.
RETURN
GND
Dielectric Withstand
Test Voltage
Max. Leakage
Current
Test Time
Test Current
Voltage Limit
Maximum
Resistance
Test Time
800 VAC
5 mA
1 sec
10 A
< 12 V
0.2Ω
5 sec
EXIT
SET
ACW / DCW / IR / GB TESTER
Although most IR testers have a variable output voltage, the test is usually specified at 500 or 1000 volts.
Ground Bond
Before testing, turn on all power switches on the appliance so that all internal circuits are tested. Ensure the appliance is
disconnected from all other circuits.
The IR test is sometimes required by safety agencies to be performed subsequent to the Hipot test in order to make sure that
the DUT’s insulation was not damaged as a result of the high voltage applied to it.
Insulation Resistance Test Considerations
60335 Testing Example Setup
Using Test Leads
There are a few things to keep in mind when running an IR test:
• Since most products are capacitive in nature it is important to allow the test to run for an adequate period of time before
recording any measurements. Test times can vary but a 1-10 min test should supply a stable reading.
Test Procedures
1. Connect the RETURN lead from the test tester to the metal chassis of the DUT. This will act as the return point for
both the Hipot and the ground bond tests.
2. If using test leads, connect the line and neutral (shorted together) of the fan’s three prong cord to the high voltage
terminal of the Hipot tester. If using a universal style adapter box, connect the high voltage lead of the adapter box
to the HV port on the tester. High voltage will be applied to the line and neutral plug conductors shorted together.
3. If using test leads, connect the ground pin of the fan to the HIGH CURRENT or CURRENT terminal on the ground
bond tester. If using a plug in style adapter box, connect the high current lead of the adapter box to the CURRENT
port on the tester. Current will be injected into the ground pin when using an adapter box.
4. Plug the fan’s three prong cord into the box if using the plug in style adapter box.
5. First, the ground bond test is run to ensure that the grounding circuit is sufficient for the product. Set the ground
bond test to the parameters listed above.
6. Set the Hipot test to the parameters listed above.
7. Stand back from the DUT and press the TEST button. Take note of the test results.
• It is always a good idea to ramp up the voltage over a period of time. This ensures the DUT is not subjected to a voltage
surge that could damage it. This will also help avoid false failures due to inrush current (as with the DC Hipot test).
• The most important parameter for the IR test is the resistance low limit. If the resistance is too low, more current will flow
and the test will fail. Remember, the higher the resistance, the better the insulation. If no IR value is specified by and agency
specification, the insulation resistance for an IR test at 1000 V or less should be at least 1 MΩ.
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Safety Made Simple®
60335 Testing Example Setup
Using Adapter Box
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TEST APPLICATION EXAMPLES
TEST APPLICATION EXAMPLES
RV Testing
Mobile Home Testing
The R.V.I.A (Recreation Vehicle and Industry Association) sets forth testing to cover 120 VAC Electrical Systems. The R.V.I.A. bases
this testing off of the National Electrical Code Article 551:
With the regulations put in place by the U.S. Department of Housing and Urban Development (HUD), Hipot testing is
important to modular and RV home manufacturers:
R.V.I.A. (NEC 2011 Article 551) Section 551.60 Factory Tests (Electrical)
R.V.I.A Section 551.60 – Dielectric Voltage-Withstand Test for Recreational Vehicles7
H.U.D. #24 CRF 3280.810(a)– Dielectric Voltage-Withstand Test for Recreational Vehicles
Test Time
Test Voltage AC
Test Voltage DC
Test Time
Test Voltage
60 sec
900 V
1280V
60 sec
900 - 1079 V
1 sec
1080 V
1530 V
1 sec
1080 - 1250 V
All switches and other controls shall be in the “on” position. Fixtures, including luminaries and permanently installed appliances, shall not be required to
withstand this test.
7
This Hipot test will generally be run at the breaker box of the R.V. In recent years, more manufacturers have adopted the DC
Hipot test due to the fact that all lights and appliances can remain installed in the R.V. during the test. An AC Hipot test could
potentially damage such components. For AC testing, such elements usually have to be removed which adds considerable
difficulty and complexity to the production line.
For this example, an operator will test an RV with a DC Hipot tester. The operator will use a safety test probe and alligator clip
style RETURN lead.
Test Procedure
The test is conducted between the live parts and the manufactured home’s ground, as well as between the neutral and the
manufactured home’s ground. It is important to refrain from conducting the test from phase to phase or between hot and
neutral in order to avoid damage to any appliances that might be connected.
As with the R.V. test example, this test is generally performed at the breaker box of the modular home.
Test Procedure
1. If the neutral bar is shorted to the ground bar, remove this short prior
to testing. This short will cause the hipot tester to indicate a false failure.
2. C
onnect the RETURN lead to the grounding point in the breaker box.
1. If the neutral bar is shorted to the ground bar, remove this short prior to
testing. This short will cause the hipot tester to indicate a false failure.
3. Set the Hipot test for 1250 VAC. Set the test time for 1 sec.
2. Connect the RETURN lead to the grounding point in the breaker box.
4. Contact the first breaker with the Hipot safety probe.*
3. S et the Hipot test for 1530 VDC. Set the test time for 1 sec.
5. Push the test button and wait for the test to complete.
4. Contact the first breaker with the Hipot safety probe.*
6. Repeat steps 4 and 5 for all breakers.
5. Push the test button and wait for the test to complete.
6. R
epeat steps 4 and 5 for all breakers in the RV.
*If there is a main breaker in the breaker box, short all lines (L1 and L2) and neutral together. Apply HV to the shorted lines. If you test in this fashion, you
only need to run one hipot test on the main breaker
*If there is a main breaker in the breaker box, short all lines (L1 and L2) and neutral together. Apply HV to the shorted lines. If you test in this fashion, you
only need to run one hipot test on the main breaker
18
Scan for R.V.I.A Information
Scan for H.U.D. Testing Information
Recreation Vehicle Industry Association Standards
rvia.org
Manufactured Home Construction and Safety Standards
ecfr.gov
Safety Made Simple®
hipot.com
19
TEST APPLICATION EXAMPLES
Test Station Safety Procedure Checklist
UL 1598 and IEC 60598 - Luminaries
Prior to testing
A fluorescent lamp ballast assembly needs to be tested for Hipot. The ballast has an input voltage range of 120-277 VAC.
According to UL 1598 section 17.1.3:
Visually inspect test lead for signs of excessive wear. If a test lead appears worn or damaged, do not use it. Find a
replacement lead.
“The test voltage shall be 1000 V for incandescent type luminaries and 1000 V plus twice the rated input voltage for all other
types of luminaire.”
Since this is not incandescent type ballast, the test voltage would be:
1554 VAC = 1000 VAC + 2 * 277 VAC
Verify the high voltage output is OFF before making any connections
Connect the low return side to the tester first in order to prevent the DUT from becoming energized.
If using alligator style clip leads, securely connect the clip lead to the exposed metal parts being tested.
If using a tester with a panel mounted receptacle, first connect the return clip lead and then plug the product’s cord set into the tester.
When using a test fixture, be certain that it is properly closed and that all guards are in place.
Double check the connections before beginning a test.
Double check all tester settings before the test.
LED Ballast
While Testing
Handle both return and high voltage clips by their insulating material; never by the conductive metal.
Keep the leads on the bench as close to the DUT as possible and avoid crossing test leads.
Neatly coil any excess lead halfway between the tester and the DUT
Never touch any of the cables, connections or DUT’s during a test.
Test Procedure:
1. Connect the RETURN lead of the Hipot tester to the metal chassis of the ballast. Often times, the chassis is connected to a
green grounding wire. This will provide the return point for leakage current to flow and the tester to take a reading.
Have a “hot stick” on hand when doing DC testing (a hot stick is a non-conducting rod about two feet long with a metal
probe connected to ground at one end). If a connection comes loose during the test, use the “hot stick” to discharge any
surface that contacted the tester’s hot lead - simply turning off the power is not sufficient.
After the test, turn off the high voltage.
Discharge DC-tested products for the proper length of time.
General Items
Develop a standard test procedure and always follow it; don’t take any shortcuts.
Turn off the test tester if it is not in use.
2. C
onnect the white and black wires (shorted together) of the ballast to the high voltage lead of the Hipot tester. This puts all
of the mains circuits in the ballast at high potential.
3. Set the Hipot test to the parameters per UL 1598 section 17.1.3.
4. Stand back from the DUT and press the TEST button.
20
Safety Made Simple®
hipot.com
21
Safety Reference Chart
Standard /
Harmonized
Standard
IEC/UL 60601-1
3rd Edition Medical
Electrical Equipment
Testing
Type
Glossary
Dielectric Withstand
Test Voltage
500 – 4000 VAC
or 707 – 5656 VDC
Performance
Production
Max I.
Ground Bond/Continuity
Test
Time
Insulation
Resistance
Suggested
Model #
Test
V
Current Limit
Max. R
10-25 A
≤6V
≤ 0.1 Ω
5s
110% x
5-10 mA
rated V
N/A
6330
1 or 60 s 10-25 A
≤6V
≤ 0.1 Ω
5s
N/A
N/A
4320, 4520
60 s
Test Time
No Breakdown
1000 – 3000 VAC
Earth
Leakage
Test
Voltage Max I.
Test V
Min Slaughter Tester
Time Limit R
IEC 60598-1
Luminaires
900-1079 VAC
or 1273-1526 VDC
No Breakdown
60 s
Continuity
N/A
N/A
Production
1080-1250 VAC
or 1527-1768 VDC
No Breakdown
1s
Continuity
N/A
N/A
294, 295,
296, 297
Performance
900 VAC or 1280 VDC
No Breakdown
60 s
Continuity
N/A
N/A
294, 295,
296, 297
Production
1080 VAC or
1530 VDC
No Breakdown
1s
Continuity
N/A
N/A
294, 295,
296, 297
500 – 2400 VAC x rated V
No Breakdown
+ 2400 VAC
60 s
≥ 10 A
≤ 12 V
0.1 – 0.2
Ω
≤ 120 s
1.06 x
rated V
N/A
6330
Dielectric - An insulator sandwiched between two conductors. In the case of a Hipot test, the DUT’s insulation is considered
to be a dielectric.
1s
≥ 10 A
≤ 12 V
0.1 – 0.2
Ω
No time
specified
N/A
N/A
4520
DUT - Device Under Test
60 s
40 A
≤ 6.5 V
≤ 0.5 Ω
120 s
1.06 x
rated V
N/A
6330
1s
40 A
0.1 – 0.2
≤ 12 V
Ω
60 s
≥ 10 A
Performance
Production
Performance
400 – 2500 VAC
500 V – 2400 VAC x rated
No Breakdown
V + 2400 VAC
Production
Performance
5-30 mA
400 – 2500 VAC
5-30 mA
500 – 4 x rated V + 2000
No Breakdown
VAC
Production
1000 VAC - 1000 VAC x 2
x rated V
Production
1200 VAC
EN 60204-1
Electrical Equipment
of Machines
Performance
Production
EN 60950-1 EN
50116 Information
Technology
Equipment
Performance
UL 60950-1 CSA
22.2 No. 609501 Information
Technology
Equipment
20
60 s
Production
Production
1s
2 x rated V or
1000 VAC
No Breakdown
60 s
Rated V
N/A
0.5 – 10
mA
30 A
≤4V
≤ 0.1 Ω
120 s
60 s
500
VDC
4520
1-4
MΩ
Continuity
≤ 0.1 Ω
Continuity
1s
0.2 10 A
≤ 24 V
Refer to
Section
18.2.2
60 or 120 s
No time
specified
N/A
< 300 V
0.5 mA
N/A
No time
specified
1000 VAC + 2 x rated V
or DC equivalent
No Breakdown
1000 - 3000 VAC
1000 – 3000 VAC
or 1414 – 4242 VDC
1000 – 3000 VAC
or 1414 – 4242 VDC
Safety Made Simple®
60 s
Continuity
1s
Continuity
N/A
No time
specified
500
VDC
≥2
MΩ
0.5 – 3.5
mA
60 s
N/A
30 A
≤ 12 V
≤ 0.1 Ω
60 s
1-4s
25 A
≤ 12 V
≤ 0.1 Ω
1-4 s
60 s
≤ 40 A
≤ 12 V
≤ 0.1 Ω
60 s
4320, 4520
N/A
295, 296
N/A
6330
N/A
294, 295,
296, 297
500 V
≥1
MΩ
4320, 4520
294, 295,
296, 297
< 300 V
120 s
6330
294, 295,
296, 297
N/A
< 300 V
No Breakdown
0.25 –
3.5 mA
0.25 –
3.5 mA
500 V
≥ 50
KΩ
N/A
60 s
N/A
< 300 V
Class II Product - A product that contains additional safety precautions such as double insulation or reinforced insulation.
There are no provisions for protective earthing or reliance upon installation conditions, for these products.
Direct Current - The flow of continuous electric current in one direction that can change in magnitude but not polarity.
Design/Type Test - A safety test performed on a prototype model during the design phase of the product.
Ground Bond Test - A high current test that checks the integrity of a Class I product’s safety ground connection.
Ground Continuity Test - A low current test that verifies a Class I product’s safety ground connection is continuous.
Not Specified - Responsibility of Manufacturer
Performance
Production
N/A
0.25 –
5.0 uA
No Breakdown
Production
Performance
≤ 0.5 Ω
≤ 0.1 Ω
≤ 10
5 - 60 s 25 or 30 A V or ≤ or <4 V
12 V 0.133 Ω
840 - 11940 VAC or 1200
No Breakdown 5 s max
- 7500 VDC
ramp
Continuity
up
2s
dwell
Performance
UL 45A Portable
Electrical Appliances
≤ 12 V
No time
specified
0.25 –
5.0 uA
Not Specified - Responsibility of Manufacturer
Performance
UL 1598 Luminaires
IEC/UL 61010-1 &
CSA 22.2 No. 610101 Laboratory Control
Test & Measurement
Equipment
Class I Product - A product in which an additional safety precaution is provided in the form of a connection of the
equipment to earth ground. The protective earth conductor in the fixed wiring of the line cord is attached to the chassis in
such a way so that all accessible metal parts cannot become live in the event of a failure of the basic insulation.
Performance
R.V.I.A. (NEC)
UL 60335-1
Household Electrical
Appliances
Breakdown - Catastrophic failure of a product’s insulation resulting in excessive leakage current flow.
294, 295,
296, 297
H.U.D. Specification
#24 CFR 3280.810
IEC 60335-1
Household Electrical
Appliances
Alternating Current - is the flow of electric current which reaches a maximum in one direction, decreases to zero, then
reverses itself and reaches a maximum in the opposite direction. The cycle is repeated continuously, changing polarity and
magnitude with time.
500 V
N/A
60 s
500 V
Insulation - A material that is a poor conductor of electricity. Used to isolate electrical circuits from ground and each other.
Insulation Resistance Test - A high voltage test used to record the resistance of a product’s insulation.
Leakage Current - Current that leaks through a product’s insulation to ground.
Nationally Recognized Testing Laboratory (NRTL) - Independent or Federally-associated regulatory agencies that create
and oversee electrical safety testing.
NRTL Listing - Certification that a sample product has been tested by an independent third party agency (National
Recognized Testing Laboratory) and has complied with national standards applicable to that particular product. Once
certified, an agency label may be applied to the product to indicate compliance.
Production/Routine Test - A test performed on 100% of manufactured products after they are assembled, but before
shipment.
Safety Ground - An extra low-impedance connection from the metallic chassis of a product to earth ground. Acts as a
current path under fault conditions.
6330
294, 295
≥2
MΩ
Hipot Test - A high voltage test used to stress the insulation of a product and measure the resulting leakage current.
6330
Question about technical definitions? We’re here to help!
Technical Support +1-800-504-005
4320, 4520
≥2
MΩ
6330
No Breakdown
1–6s
Continuity
N/A
N/A
294, 295, 296
hipot.com
21
Questions?
We’re here to help.
+1-800-504-0055
28105 N. Keith Drive, Lake Forest, IL 60045 USA
+1-847-932-3662 • 800-504-0055 • Fax 847-932-3665 • hipot.com • [email protected]
© 2016 Slaughter Company, Inc.
V1.0 2/2016
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