Electrical safety risks include shock, arc flash, and arc blast. Shock can cause electrocution and death from contact with any live electricity source. An arc flash is created by a short circuit and passes current through ionized air, while an arc blast is the explosive result and causes hazards like heat, shock waves, and metal shrapnel. Transients from switching equipment can trigger an arc flash. Proper personal protective equipment and following guidelines like NFPA 70E can reduce risks when working with electricity. Test equipment must be rated for the voltage category of the circuit and independently certified to safety standards to avoid hazards.

1. Electrical
Measurement Safety
You’re right to be
concerned
Presenter: Curt Geeting, Fluke Corporation

2. Risks from electrocution and shock hazards
Shock
• Contact with any source of electricity that causes a sufficient current
through the skin, muscles, or hair.
• Shock can cause electrocution and death.

3. Risks from an arc flash
Created by a phase to phase or phase to ground short circuit.
• Current passes through the air.
• Ionized air (plasma) is a good conductor.
• Once an arc begins, it feeds off any matter in its path and vaporizes it.
• Duration is under one second.

4. Risks from an arc blast
The explosive result of an arcing fault.
• Vaporized conductors are rapidly expelled creating such hazards as intense heat,
thermoacoustic shock wave, molten metal, shrapnel, blinding light, toxic smoke
and contact with energized components.

5. Transients can trigger an arc flash
What causes a transient?
• Motor or other inductive load switching off
• Equipment malfunction
• Utility load switching
• Adjustable speed drives
• Lightning strike
480 V rms, +/- 678 V peaks
Spikes up to
8,000 volts
Transients:
• Are invisible and largely unavoidable.
• May last under 100 mS but can be extremely dangerous.
• May overcome test equipment input protection causing an
arc/short in the tester.

6. What likely causes these incidents?
1. Racking a circuit breaker
– Inserting or removing a breaker on a
live bus.
2. Lose panel wiring
– A lose conductor that shorts across
another conductor or ground.
3. Removing panel covers
– Retaining screws and fasteners fall
into an unsecured panel against a
live bus.
4. Hand tool shorted across two phases
– Experienced electrician cuts into live
cable with cable shears, shear handle
touches another phase.
5. Using incorrect test probes
– The user gets distracted or hand
slips while measuring phase to
phase or phase to ground while
using old style ¾ inch probe tips.
6. Misuse of measurement tools
– Measuring across phases with
an inline amp meter creating a
short circuit.
– Measuring continuity on a live
circuit with a tool that cannot
withstand full voltage.
– Accidental shorting of phases with
a test lead tip that is too long for
the safety category.

7. 1NFPA-70E –
Standard for Electrical Safety in the Workplace
As the work environment and the type of job become more hazardous,
the need for protection increases.
Follow industry guidelines
NFPA-70E1 addresses:
Safety-related work practices
Maintenance of safety equipment
Safety requirements for special equipment
Safety related installation requirements

8. Boundaries apply
when workers are
exposed to energized
electrical conductors
or circuit parts.
Safe working distances
Flash limits of approach

9. PPE Category Required Minimum Arc Rating of PPE Typical Layers
1 4 Cal/cm² 1
2 8 Cal/cm² 1 or 2
3 25 Cal/cm² 2 or 3
4 40 Cal/cm² 3 or more
The higher the electrical environment, the stronger
the personal protective equipment must be to withstand
an arc-flash incident.
Images courtesy of Salisbury
PPE – Personal Protective Equipment
The PPE category is used to determine the necessary arc rating of a garment
worn during a given job task.

10. NFPA: Test instruments are part of PPE
(Article 110.4):
• Shall be rated for circuits and equipment to which they will be connected*
• Shall be designed for the environment to which they will be exposed, and the
manner in which they will be used.*
• Shall be visually inspected before use. Defective or damaged equipment must
be repaired and tested before being used again*
• The insulation of protective tools, including voltage test indicators, shall be verified
by test and inspection (Article 110.4(5))
* NFPA 70E 110.4(A), 2015 Edition
Reduce the risk by using the right test equipment
IEC 61010: International Standards for low voltage
“test, measurement and control equipment”

11. Measurement Category locations or ratings
CAT IV Three-phase at utility connection, any outdoor mains conductor
CAT III Three-phase distribution, including single-phase commercial lighting
CAT II Single-phase receptacle connected loads
The level and energy of voltage impulses are dependent on the location.
The closer the location is to the utility supply, the higher the available fault current and the higher
the category.
IEC 61010 defines three measurement locations or categories:
The greatest danger from transients is in the high
categories, because they could trigger an arc blast.

12. Ensure your test equipment meets or
exceeds industry standards
To provide better protection for electrical workers
standards have been developed for test equipment used in environments of 1000
volts or less, including 480 volt and 600 volt three-phase circuits.
1International Electrotechnical Commission
IEC 61010 are the group standards for
low voltage “test, measurement and
control equipment”

13. First the category, then the voltage
First know the category you are working in, then choose the appropriate
voltage rating
• The working voltage could be 1,000 V, 600 V or 300 V
• Equipment can be dual rated, meeting both requirements
• If you measure power circuits, you should use a CAT III-600 V or CAT IV-600 V/CAT III-1000 V
meter, in addition to CAT IV-600 V/CAT III-1000 V test leads and probes
Voltage rating by itself can be misleading
• CAT III-1000 V (withstands 8 kV transient) is safer than CAT III-600 V (withstands 6 kV transient)
Bottom line and most importantly,
know the measurement category and voltage you are working in.

14. The test equipment should be
independently tested, marked
and certified.
CAT III-600 V
CAT III-1000 V
CAT IV-600 V
CAT III-1000 V
CAT IV-600 V
Look for CAT markings between input jacks

15. What if I can’t find a rating?
Older Fluke 70 Series-III
CAT II-600 V
Original
Fluke 70 Series
UNDER RATEDNOT RATED
Meters and testers designed and produced prior to 1997
no longer meet code and therefore should be replaced.

16. Independent testing and certification
• IEC sets standards, but does not test or inspect for compliance.
• A manufacturer can claim to “design to” a standard with no independent verification.
• To be UL listed, or CSA or TÜV certified, a manufacturer must employ the
listing agency to test the product’s compliance with the standard.
• Look for the listing agency’s emblem on the meter.
“Listed” vs. “designed to”
Tester must be independently tested,
marked and certified.

17. Read and understand the manufacturer’s
instructions

18. 1. Verify the voltage detector function is working properly.
2. Make sure the detector is rated for the level of voltage being measured and
is sensitive enough for your application.
3. Make sure that you also wear the appropriate PPE based on the
environment you're in.
4. Make sure the hazardous voltage is not shielded.
Use only a digital multimeter or contact type voltage
tester to test for the absence of voltage.
Non-contact voltage detectors
Non-contact voltage
detectors are a quick,
inexpensive way to check
for the presence of live
voltage on ac circuits,
switches and outlets
before working on them.

19. Live-dead-live testing
Verify the operation of the contact voltage tester
Before beginning the absence of voltage test, check the
test instrument to ensure it is working properly in
accordance with NFPA 70E Article 110.9 (A)(4)
1. Wearing proper PPE, measure a voltage similar to the voltage of the
equipment about to be tested. This would include whether it is ac or dc
and approximately the same magnitude.
2. Now test the circuit that is supposed to be de-energized.
3. Once testing is complete, re-verify the meter is still functioning properly
by going to the same known voltage source and making another
measurement.

20. Operational readiness test
Verify proper operation of test tools on a known voltage source before and after
absence or presence of voltage testing is performed.
Several options:
1. Use a convenient electrical outlet (if available)
2. Access live conductors (posing unnecessary risk)
–Suit up in appropriate PPE arc flash gear
3. No power exists
• The Fluke PRV240 Proving Unit provides a regulated
and fixed ac or dc output voltage of 240 volts specifically
to allow for verification testing of Multimeters,
Clampmeters or testers
When test instruments are used for testing the absence of voltage on conductors or circuit parts
operating at 50 volts or more, the operation of the test instrument shall be verified on a known
voltage source before and after an absence of voltage test is performed.
NFPA70 E 2015 edition Article 110.4 (A)(5) Operation Verification proposed wording change

21. Double insulation, finger guards, shrouds and recessed input
jacks protect against electric shock from accidental contact
with live circuits.
Perform an inspection of the test leads
 CAT III-1000 V or CAT IV-600 V/CAT III-1000 V rating
 Wear indicator on lead wires
 Shrouded connectors
 Finger guards
 Insulation not damaged (melted, cut, cracked or
stretched)
 Connectors: no insulation pulled away from end
connectors
 Probe tips: not loose or broken off (too short)
 4mm exposed probe tips in CAT III or CAT IV
environments
Test Lead Safety Checklist
Don’t let test leads be a weak point!

22. The amount of exposed metal at the tip of the test lead must match
the energy potential of a given measurement
Minimize exposed metal for safety
In accordance with IEC 61010-031
Safety requirements for hand-held probe assemblies for electrical measurement and test.
Some leads offer extendable tip shrouds
to meet the reduced tip length requirement
Other leads come with tip guards
to minimize exposed metal
The higher the CAT rating the less exposed
metal is allowed at the tip of the test lead.
CAT II – 19 mm (0.75 inch)
CAT IV – 4 mm (0.16 inch)

23. The bottom line ― Safety First
Best practices include:
1. Whenever possible, work on de-energized circuits.
• Follow proper lock-out/tag-out procedures
2. Use well maintained tools and appropriate personal
protective equipment
according to NFPA 70E.
• Safety glasses, insulated tools, insulating gloves, arc-
rated clothing,
arc shields, flash suits, insulating mats, etc.
3. Don’t work alone.
4. Practice safe measurement techniques.
• Always connect the grounded lead first, hot second
• Disconnect the hot lead first, grounded lead second
5. Use the live-dead-live test method.
• Test known circuit, measure target circuit, then re-test
known circuit

24. Built-in protection devices guard against the
most common safety hazards:
Overload protection on
all functions
1000 V high
energy fuses
CAT IV-600 V
CAT III-1000 V
Protection that’s designed in
An industrial grade Fluke meter devotes 10 to 15%
of its components exclusively to protection
1. High voltage transients and danger of arc-over
2. Voltage contact while in continuity or resistance
mode
3. Voltage measurement while test leads are plugged
into the amps jacks

25. Common errors with measurement tools
Connecting a meter to a voltage source with the meter configured
for inline amp measurements.
The amps mode on a meter is almost a short circuit
Measuring ohms or continuity on
a live circuit.
Most older meters cannot handle the full
voltage on the ohms function

26. Handheld Test Tool Safety
Last known earthly
residence of automotive fuse
used to replace original fuse
Test leads
survived intact
How not
to save
time...

27. The wrong
meter to use
on a power
circuit.
Probe tips
burned off
Poor quality
leads and
probes led to
injury.
250V fuse
didn’t open in
time
Handheld Test Tool Safety

28. Fingerprints
burned into
probes
The electrician suffered
severe burn injuries on
his hand and arm.
Handheld Test Tool Safety

29. Fluke incorporates specially designed “high-energy” fuses in our digital multimeters
Designed to keep the energy generated by an electrical short
within the fuse enclosure
• Limit the amount of time current is applied and oxygen
available for combustion
• In addition to the specially designed fuse element,
the high energy fuse is filled with sand
Protection devices provide additional safety
30
High temperatures (up to 10,000F) generated by the energy will melt
the sand and turn it into glass, smothering the fireball by cutting off
the available oxygen

30. Common DMM safety hazards
• Measuring voltage while test
leads are in the current
jacks: short-circuit!
Protection: Fluke meters use
high energy fuses.
• Contact with ac or dc power
source while in Ohms mode.
• Using meter above rated voltage, i.e., on medium voltage
circuits.
• No Protection above rated voltages
Protection: Fluke meters have “Overload Protection”.
Functions are self-protected to the meter’s rated voltage.
Three common errors that are avoidable

31. PRESENTER SLIDE: HIDE
Meter Examples/Demonstrations
• Hold up Fluke 87 with leads in Amps Jack
• To measure amps in-line, you wire your meter in series with the circuit. In order not to interfere
with the measurement , you want your meter to look like a piece of wire. Another word for a
piece of wire is a short circuit. So when you have your leads in the amps input terminals, you
have a dead short across these probe tips. That is why it is so important that your meter has
fused input jacks. And not just any fuse, but a specially designed high energy fuse.
“ If this happens with a properly fused meter, the fuse will blow, and you will not even know it.
to check the fuse, you open the meter, pull out the fuse, close the meter or get another meter, and
measure the ohms or continuity to see of the fuse is open. There is a much easier way to do this,
without even having to open up your meter
The black input jack is common for all measurements. So, by measuring across the Common and
Amps input jacks in Ohms, you can check your fuses without opening the case
(show how to do this while talking)
Never change a fuse with the wrong fuse. It is very important to replace the fuse with the
manufacturer’s suggested high energy fuse Now most of the time you will be using a current clamp
to measure current safely
(play amps input-fuse animation)?

32. Safety Inspection
• In a power circuit, use current clamp accessory.
• In low energy ckt, 10A or less, open the circuit:
– Measure in series (current is the same in a series circuit). The
amps circuit resistance must be small, to have a minimal effect
on the current. This low impedance input requires fuse
protection.
Caution!!! Don’t leave the leads in mA or A input jacks
and then take voltage measurements.
A, mA/uA inputs
COM
Ammeter circuit inside DMM
Amps inputs need high energy fuses

33. PRESENTERS SLIDE: HIDE BEFORE
PRESENTATION:Next 3 slides
ClampMeter Examples/Demonstrations
• Hold up Fluke 376 with iFLEX plugged into it
• “Most of the time you will be measuring current with a current clamp accessory or ClampMeter. This is a
safer, noncontact method for measuring current.
• There are two type of current clamps and ClampMeters: AC and AC/DC
– AC CLAMP SLIDE: AC is just a coil of wire that picks up the magnetic field (AC Current clamp slide) There are new technologies that
make this easier than every (do iFLex explanation)
– AC DC CLAMP SLIDE: AC/DC uses an electronic sensor, because DC current generates a much smaller magnetic field around the
wire. (DC Current clamp slide)
• This applied to current clamp accessories you plug into your meter as well. (How DMMs measure
current slide). One of the most common questions on our 800-44-FLUKE technical hot line is “I plug in
my new clamp meter accessories into my meter and it does not work”
• Process Loop slide: Does any one have to check 4-20 mA control loops? Until recently, the only
way to do this was too break the circuit. Now there are new test tools that can measure the loop
currents with out breaking the loop (hold up Fluke 771 or 773). For these , it is very important to zero
out the ClampMeter next to the wire before making the measurement.
• HOLD 771, 323, iFLex UP“ the moral of this story is that, depending on the size of the wire and the
level of current you are looking to measure, there are different size ClampMeter openings to get the
best measurement.

34. How DMMs Measure Current
• Current transformer (CT) style preferred for AC:
– CT clamps have good noise immunity: recommended for
AC Variable Speed Drives and other noisy environments
• How to use: use A inputs
– They are CTs with 1:1000 turns ratio:
1 A on primary (circuit being measured) =
1 mA on secondary (input signal to DMM)
– Connect probe to Amps jacks of DMM.
– Select A
– 87: select manual range of 4000mA for direct
reading of Amps (since 1 mA = 1 A)
– 26: Select manual range of 4.000A. Mentally
move the decimal three places to the right: .089 = 89 Amps
• True-rms measurements require a T-rms meter.
AC Current Clamp Accessories

35. How DMMs Measure Current
• AC/DC clamps: use V inputs of DMM
– Use Hall-effect technology:
require batteries in clamp
– 1 mV per Amp.
– Select Vdc or mVdc to measure DC current
– Select Vac to measure AC current
• True-rms measurement (of ac current) requires a
T-rms meter.
• Always “Zero” clamp next to wire before
measurement to eliminate incorrect
measurements from AC magnetic fields in cabinet
AC/DC Current Clamp Accessories

36. • In power circuits, clamps are used to measure amps.
• Two types of clamps: AC or AC/DC
(Scope clamps have BNC connectors: AC or AC/DC both output mV. )
How DMMs Measure Current
Current Clamp Accessories
AC
Model: 80i-400
AC/DC
Model: i410, i1010
Output signal Current Voltage
Scale factor 1 milliAmp
per Amp
1 milliVolt
per Amp
Sensor Current
Transformer
Hall effect
Battery No Yes

37. 2200 ºC
ZERO SPAN
Process Loops
4 to 20 mA
Transmitter
Sensor
Indicator
Loop
Supply
4-20 mA process signals
• Very low current, in line
measurement
• Measure transmitter o/p:
• Source 4-20 mA to indicator
• Simulate 4-20 mA
Fluke 789

38. Fluke 771 mA Process Clamp Meter
• Measure mA signals without breaking the loop
• Best in class mA measurement accuracy and resolution
• Save time and money troubleshooting PLC analog I/O
and process loops
• Detachable clamp with extension cable
• Dual display with both mA and % of span readouts
• Measurement spotlight illuminates hard to see wires.
• Fluke 772 and Fluke 773 add full 4-20mA Source and
Measurement for loop calibration and troubleshooting
Measure 4-20 mA signals
without breaking the loop.
Innovative new approach to measuring mA loop signals

39. Misuse of DMM in Ammeter Mode

40. Safety Inspection
Step 1: Plug test lead in V/  input. Select  .
Step 2: Insert probe tip into mA input. Read value.
Step 3: Insert probe tip into A input. Read value.
• Is the fuse okay? What would an open fuse read?
Checking fuses on the Fluke 87-IV
Step 1: Select (w/o test leads).
Step 2: Plug lead into mA and A input.
Step 3: Listen for Beeps=fuse is good
(special automatic warning circuit to prevent you from
doing this)
Checking meter fuses on most meters
DMM BASICS
Fluke 87: With lead in mA or A, select  and listen

41. Common errors with measurement tools
Measuring ohms or
continuity on a live circuit.
Most older meters cannot handle the full
voltage on the ohms function

42. PRESENTER SLIDE: PRACTICE and HIDE:
Connecting Voltage while in the Ohms Demonstration
• Hold up Fluke 87 with leads plugged into Fluke 1587, 87=DC Volts; 1587 = Insulation Test mode
• “Part of the IEC 61010 Safety rating is if I have a 1000 volt meter, I should be able to connect
1000 volts in the volts terminals in any function, without anything happening to me or the meter.
• “Here I am applying 1000 volts to the input of this meter (Hold up 87-V with 1587 locked in 1000
mode output, walk around and show audience 1000V displayed on meter).
• I switch to ohms mode and apply the same 1000V. (show meter face “OL”) Those of you who
have been around a while probably instinctively wanted to step back a little. Why? With older or
unprotected meters, when you do this, if you are lucky you typically would see a puff of smoke
and be in the market for a new meter. If you are unlucky, you’re holding a fire ball
• I’ll go back to volts, and see how the meter is still working fine? (Show 1000V on meter display)
• What I am using here is a mega-ohm meter, or insulation resistance tester. This pressure tests
electrical wires, motor coils and such, to see if the insulation is going bad. Just as I would use
water pressure to look for leaks on a hose, we use Electrical Pressure, or VOLTS, to pressureize
the wire and look for leaks in t he insulation. It is also a great way to test new wiring you just
installed, instead of turning everything on and looking for smoke.
• Now while you have your meter with you at all times, chances are the megaohmmeter is back in
the shop. What we’ve done is take the meter (show Fluke 87 in front) and the megger (show
1587 in front with other hand) and built them into one unit ( move and hold the Fluke 87 behind
the Fluke 1587). This way you always have an insulation tester with you, and you are more
likely to make these tests, instead of having to walk back to the shop.

43. Boundaries apply
when workers are
exposed to energized
electrical conductors
or circuit parts.
Safe working distances:
Work Outside the Danger Zones
Flash limits of approach

44. New Wireless measurement tools
Provide physical separation in an arc flash environment
One technician can do jobs that would
otherwise require two people
Connect the meter or clamp to a conductor, remove
the display and walk across the room to operate
controls or remove protective equipment, all the while
watching real-time readings.

45. Enhance safety with wireless tools
Fluke Connect™ enabled tools for data transfer

46. Fluke Connect Wireless Measurement Tools

47. Fluke 1736/1738 Power/Energy Loggers
Monitor, Record and Troubleshoot behind closed doors!
• Key Power Measurements
– All measurements are measured and logged to eliminate the risk
of not recording the important parameters.
• Fluke Connect App Compatible
– Enables data to be viewed without having to suit up and can
remotely view measurements – no need to visit panel
• Convenient Instrument Power
– Powered from the measurement circuit means there’ no need to
find a power outlet and run power cord extensions
Improves measurement efficiency, improves safety while measuring to get to
answers more quickly and reliably

48. Fluke Connect Wireless Measurement Tools

49. View multiple measurements simultaneously
with Fluke Connect™ wireless tools
View up to 10 live measurements
simultaneously from energized
equipment well outside of
arc flash boundaries
• 3-phase current and voltage
• Cause and effect relationships
• Log intermittent problems over time
• Verify lockout/tagout electrically safe status
Save all measurements
wirelessly, for each piece of
equipment, in one place, with the
same one App for all testers.
• Electrical measurements
• Temperature measurements
• Power and Energy usage
• Thermal Images
• Vibration
:
Build your equipment maintenance database over time while doing your normal work!

50. The Safest Way to Measure Electricity is to
Get No Where Near It!!

51. View the degree of heat coming from various
components, all in a single image
Most equipment’s failure mechanisms involve a significant rise in operating
temperature long before catastrophic failure occurs
• Equipment remains operational
• Captured at a safe distance increasing
safety
• Live voltage still requires full electrical
safety precautions
• Access components and systems not
otherwise measurable, such as ceiling runs
• Help detect imminent failures in nearly all
types of equipment
• Uncover potential problems in areas that
would typically be ignored
Fluke Infrared Cameras

52. Abnormal heating associated with high resistance or excessive current flow
is the main cause of many problems in electrical systems
Analyze the invisible with Infrared
• Troubleshoot problems in electrical connections
• Detect high resistance loose connections
• Check for unbalance in 3-phase electrical systems
• Balance branch loads and identify excessive current consumption

53. Inspect indoor or outdoor switchgear and
panels safely
An IR window can help increase the safety of personnel and reduce the cost of
predictive maintenance, in compliance with switchgear codes.

54. Test instrument training and proficiency
NFPA states that “Employees shall be trained to”:
• Select an appropriate test instrument for a given task
• Demonstrate how to use a test instrument
• Interpret results
• Understand ratings of the test instrument
• Perform a visual inspection of the test instrument and accessories
• Perform an operational verification on a known voltage source
• Identify misapplication

55. Next steps: Test Equipment Safety Audit
1. Complete the on-line training course for electrical measurement safety
2. Match you working environment to the CAT rating of your tools
3. We can help Audit your test tool inventory
• Ensure compliance with industry ratings and standards
• Verify the operational readiness of your tools
• Order spare parts where appropriate
4. Make training and briefings part of your daily work

56. Electrical
Measurement Safety
You’re right to be
concerned
Thank you!

57. Special limited-time offer!
• Gift with purchase – up to $1350 value
• Go to www.transcat.com/deals for more details
Electrical Measurement Safety Fluke Corporation © 2016

58. Questions or Comments?
Email Nicole VanWert-Quinzi
nvanwert@Transcat.com
Transcat: 800-800-5001
www.Transcat.com
For related product information, go to:
www.Transcat.com/Fluke
Electrical Measurement Safety Fluke Corporation © 2016