Post on 12-Mar-2021
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Presented byLee Marchessault, CUSP, CUSA
President, WSSI
Electrical Safe Work Practices (OSHA and NFPA 70E)
Objectives
Explain Electrical Hazards Including Shock and Arc Flash.
Describe Approach Boundaries: Restricted, Limited, Arc Flash Protection Boundaries.
Define Training and Qualifications for Electrical Workers.
Demonstrate Personal Protective Equipment.
Describe Safety-Related Work Practices including methods to De-energize, LOTO and Verify by Testing.
Understand Wiring Requirements.
Explain updates to the 2021 NFPA 70E
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Electrical Fatality Statistics
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• All electrically related fatalitiesin 2018 were caused by electric shock, no fatalities were caused by burns.
• 61% of electrical fatalities occurred in workers aged 25 –44.
• 35% of electrical fatalities occurred in Private Residences
• 26% occurred in Industrial Place and Premises
• 13% in Street and Highway.
.
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Intense Light
Sound Waves
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Pressure Waves
Shrapnel
Hot Air-Rapid Expansion
Molten Metal
Copper Vapor:Solid to VaporExpands by 67,000 times
Electric Arcs can reach the Temperature of the suns
Surface or 35,000°
The box effect makes the arc directional increasing
the flash hazard
Severity depends on the capacity of the arcto deliver enough energy to cause a thermal
burn of greater than 1.2 cal/cm² at 18” (NFPA)
What is an Arc Flash?
Incident energy is measured in calories/cm²The level depends on available bolted fault current,
clearing time, impedance, and distance.
What We Need to Know
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An arc flash starts from a ground fault or a short circuit.
Ground Fault
ShortCircuit
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Clearing Times of Protective Devices Table 130.7(C)(15)(a)New Note
Device CyclesCurrent Limiting Fuse .5Molded Case Breaker 1.5Insulated Case Breaker 3.0Relay Operated Bkr 1-35 kV 5.0Insul. Case with motor delay 20.0Insul. Case ST Delay no Inst. 30.0
Time Current Curve
Coordination and Short Circuit StudyRequired by OSHA 1910.303(b)(5)
Coordination and Short Circuit StudyRequired by OSHA 1910.303(b)(5)
Incident energy is directly proportional to clearing time
Arc Flash Hazard Assessment
480 volt
Not Enough
AFB 215” 96 cal/cm² @ 18” AFB 55” 18.6 cal/cm²@18”
<18” < 1.8 cal/cm²@18”
AFB < 10” .5 cal/cm²@18”
PPE Cat 4
PPE Cat 2PPE Cat 1
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PPE Cat 3
AFB 33” 7.6 cal/cm²@18”
Improper Wire Protection
Causes of Arc Flash Events
Connections not torqued properly or wired wrong
Insulated Torque wrench and screwdriver
Insulated Torque wrench and screwdriver
Causes of Arc Flash Events
Causes of Arc Flash Events
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Replacing buckets on MCC (Motor Control Center Improper use of non-insulated tools
Causes of Arc Flash Events
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Installation or employee error
Causes of Arc Flash Events Cause of Arc Flash Event
No updated short circuit and coordination study
OSHA 1910.303(b)(4) and (b)(5)
Protective Clothing after a 480 Volt Flash
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Not wearing an arcshield as the hazarddictated. Notice wherethe protection left off.
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Engineer out the arc flash hazards
DuPont electricians fabricated a racking tool reducing worker exposure by distance.
Increasing Distance
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Engineer out the Arc Flash Hazard
By remote switching
By reducing the clearing time
Arc Flash Relay
Differential Relays
Maintenance Switch
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Training
Employees shall be trained in and familiar with the safety-related work practices, safety procedures, and other safety requirements that pertain to their job assignments.
Electrical employees and those responding shall be trained to release victims from contact with exposed electric parts an shall be regularly instructed in CPR.
To be considered a qualified worker training may be in the
Classroom or on-the-job. 19
Qualified Employees
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NFPA 70E 2015 Definitions Qualified person is “One who has
demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved”. They shall als be competent and have: Skills to distinguish live parts. Skills to determine nominal voltage Understanding of approach boundaries. Understanding of special precautionary
techniques, PPE, insulated tools, etc.
Unqualified persons not allowed within
limited space
Limited Approach Boundary
Any point on an exposed, energizedelectrical conductor
or circuit path
Restricted Approach Boundary
Shock Boundaries 150-750 V
Qualified workers may enter restricted space only with appropriate
protection12”
42”
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Approach Distances for Qualified Employees(Approach Boundaries- NFPA 70E Table 130.4(D)(a)
The restricted approach boundary represents the minimum distance unprotected skin can be to energized parts [arm’s reach plus…].
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Test to Verify De-energized
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Qualified Employees shall be competent and understand:
• Proper use of special precautionary techniques, PPE, insulating and shielding material, and insulating tools.
Must be Listed
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Special Precautions
Capacitors shall be disconnected and after 5 minutes short circuited.
Consider Gradient Potentials around higher voltages.
Have adequate lighting
No open secondary on CTs
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Personal Protective EquipmentHazard Assessment OSHA Subpart S
Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.
PPE shall be maintained in safe and reliable condition and inspected.
Determine heat level in cal/cm²
AR Clothing has ATPV (Arc Thermal Performance Value) in cal.cm²
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Ugly P. 62
Protection from Shock
Assess for hazards requiring PPE
Inspect before use
Understand how to wear and use PPE
OSHA 1910.135 - ANSI Z89.1 Type I Class E and G
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OSHA 1910.136ASTM F1116-17 20kV
OSHA 1910.137References ASTM stds.
OSHA 1910.133ANSI Z87.1
OSHA 1910.95ANSI S12.42
AR Clothing
AR Clothing has an Arc Rating in cal/cm2. ATPV – Arc Thermal Performance Value
EBT – Energy Break-open Threshold
Determine heat that could be released from an electric arc (incident energy) for the job in cal/cm2.
Wear clothing with Arc Rating greater than incident energy for the job.
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Arc Flash PPE1.2 – 40 cal/cm²
Hard hat with Arc Shield and safety
glasses
FR Pants and Shirt or coveralls over cotton
Cat 2
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Leather BootsShock and Arc Flash
Protection
Balaclava
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Arc Flash Engineering Analysis
Dangerous Arc Flash Level
3516 Generator101 cal/cm² at 18”
2020 NEC
Determine PPE (Labels)
Arc Rating can be for a single layer or a multi-layer system if tested as a combination 35
Determine PPE - Layering
Layered System
Note: For over 12 cal/cm², arc rating can be a multi-layer System if
tested as a combination(shirt, pants, coverall and/or suit)
Summary: Protection for 480 volt 7.6 cal/cm²Personal Protective Equipment:8 cal/cm² pants, long-sleeved 8 cal/cm² shirt (or coveralls), Class 0 or 00 rubber gloves with leather protectors, hard hat with arc balaclava hood and arc-rated face shield min. 8 cal/cm², safety glasses (plastic rims), leather shoes, hearing protection, and for outside work AR winter-wear/rainwear.
Restricted Approach Boundary 12”
Limited Approach Boundary 42”
Flash Hazard Boundary (Calculated)
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Decision-Making Process
Worker shall be able to: Perform the job safely Identify electrical hazards Assess the associated
risks Select appropriate risk
control methods from the hierarchy of controls.
High RiskModerate RiskLow Risk
Assessing the Risk
ATS connected to main bus of 1964 Switchgear
ATS connected to switch Downstream of main switch
of 2004 Switchgear
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Electrical Job Safety Plan
Before starting each job that involves an exposure to electrical hazards, the [qualified] employee-in-charge shall complete a documented job safety plan and conduct a job briefing with the employees involved and include: Job tasks
Electrical hazard
Shock and arc flash risk assessment
Work procedures including special precautions, energy source controls [and PPE requirements]
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Job Briefing
Hazards associated with the job
Work procedures involved
Special precautions
Energy source controls (Lockout/Tagout)
Personal protective equipment
Energized areas in Substations
Emergency Response Procedures
A job briefing shall be conducted and shall cover at least the following subjects:
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Employer Responsibilities
The employer shall determine, through regular supervision or through inspections conducted on at least an annual basis, that each employee is complying with the safety-related work practices required by this standard.
Retraining shall be performed if deficiencies are identified and at intervals not to exceed 3 years.
Electrical Safety Programs is required and must be audited.
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Proper work procedures?
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Safety Related Work Practices
Live parts which an employee may be exposed shall be deenergized before an employee works on or near them unless the employer can demonstrate that deenergizing introduces additional or increased hazards. (OSHA)
A qualified person shall use test equipment to test the circuit elements and electrical parts of equipment
and shall verify that the parts are de-energized.Check meter on a live source and calibrate.
Verify De-energized
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Control Hazardous Energy Electrical Lockout/Tagout
Review Drawings/Schematics
Notify and coordinate with others
Barricade the area
Shut equipment down
Apply locks and tags for each (lock box for group LO)
Operate to ensure it is shut off
Test voltage L-D-L (Unqualified verification with controls)
Release stored energy
Return the controls to the off position before removing tags.
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Energy Isolation Devices
Push buttons, selector switches, and other control circuit type devices are not energy isolating devices.
Such controls interrupt power, but do not isolate power.
Effective Breaker LOTO Assess the Risk
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Working on or Near Live Parts
Justification for working on or near unless creates Additional/ increased hazards
Infeasible due to: Interruption of life support
Deactivation of emergency systems
Shutdown of hazardous location ventilation systems
Diagnostic testing/Troubleshooting/startup
Less than 50 volts with parameters
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Energized Electrical Work Permit
Exemptions to permit Testing
Troubleshooting
Voltage measuring
Still need safe work practices
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Working On or Near Live Parts
Inherently self-protected (ohm setting)
Protection from max voltage and impulse value from transients on this UL Cat III / Cat IV device.
Leads double insulated, shrouded and finger guards.
Training mandated.
Check at known source before testing de-energized parts (6,9, or 12 pt. test)
All voltage testers are not equal
Cat III 1000vCat IV 600v
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Test Incident
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2nd degree burns
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Test 4160 Volts with Wiggy
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Grounding Path
The path to ground from circuits, equipment, and enclosures must be permanent, continuous and effective.
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Use caution whenperforming maintenance, a difference
of potential may exist.
Temporary Portable wires
Ground fault circuit interrupter protection should be provided and utilized for all temporary cord and plug activities.
GFCI protection is required for all wet locations
Check ground pins No damaged cords Flex wire not for
permanent wiring56
Visual Inspections
Qualified persons shall visually inspect cord sets, test instruments, leads and equipment. Any defective or damaged item shall be removed from service.
Twist lock connectors must be locked before use.
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Reclosing Circuits After Protective Device Operation
Circuits that are opened by a protective device shall not be manually reenergized until it has been determined that the equipment and circuit can be safely energized.
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Guarding of Live Parts
Must guard live parts of electric equipment operating at 50 volts or more against accidental contact by: Approved cabinets/enclosures Location or permanent partitions
making them accessible only to qualified persons
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• Electrical equipment shall be free from recognized hazards that are likely to cause death or physical harm.
Electrical Equipment
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Before
Work in Workmanlike Manner
After
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Other Hazards
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Same phases wires in one conduitBees
What’s New in the 2021 NFPA 70E
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What’s New in the 2021 NFPA 70E?
Major changes to Article 110: Transferred sections from 120
and 130.
110.1(l)(1) Job Safety Planning: An informational note was added referencing an example of a job safety planning check list in Informative Annex I.
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What’s New in the 2021 NFPA 70E?
Article 100 Definitions: Balaclava: The word “hood”
and “sock” were removed, and the definition was changed to: “An arc-rated head-protective fabric that protects the neck and head except for a small portion of the facial area.”
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What’s New in the 2021 NFPA 70E?
110.1 Electrically Safe Work Condition: New informational note was added: “An electrically safe work condition is not a procedure, it is a state wherein all hazardous electrical conductors or circuit parts to which a worker might be exposed are maintained in a de-energized state for the purpose of temporarily eliminating electrical hazards for the period of time for which the state is maintained.
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110.3 Electrically Safe Work Condition shifted from Article 130.2 to prioritize and emphasize that de-energizing is a requirement of an Electrical Safety Program and the requirement to de-energize should be located before lockout requirements [ Article 120].
Article 130 now focuses on requirements related to work involving an electrical hazard.
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What’s New in the 2021 NFPA 70E?
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What’s New in the 2021 NFPA 70E?
• 110.2(A)(4) Type of Training: An informational note was added: “Classroom training can include interactive electronic or interactive web-based training components.”
What’s new in NFPA 70E 2021
New Informational Note 110.3(c) “On multi-employer work sites (in all industry sectors), more than one employer can be responsible for identifying hazardous conditions and creating safe work practices.”
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What’s new in NFPA 70E 2021
110.4(A) Testing: “Only qualified persons shall perform tasks such as testing, troubleshooting, and voltage measuring on electrical equipment where an electrical hazard exists.” (replaced “operating at voltages equal to or greater than 50 volts).
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What’s new in NFPA 70E 2021
New Section110.12 Equipment Use: “Equipment shall be used in accordance with the manufacturer’s instructions.”
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What’s new in NFPA 70E 2021
120.2(B) Lockout/Tagout Procedure: The text “The procedure shall meet the requirements of applicable codes, standards, and regulations for lockout and tagging of electrical sources” was added to require that any Article 120 compliant lockout/tagout procedure meet applicable regulations.
120.3(C) Lockout Device: Added language to align with OSHA 1910.333(b)(2)(iii)(E)
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What’s new in NFPA 70E 2021
120.4(B) (2) Stored energy (new annex R and section in 360 added for working with Capacitors)
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What’s new in NFPA 70E 2021
130.4(B) Estimate of Likelihood and Severity: The following information was inserted to provide clarity and usability by aligning with 130.5: “The estimate of likelihood of occurrence of injury or
damage to health and the potential severity of injury or damage to health shall take into consideration all of the following: (1) The design of the electrical equipment
(2) The electrical equipment operating condition and the condition of maintenance.”
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What’s new in NFPA 70E 2021
New
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…you might have a bad maintenance conditionWhat’s new in NFPA 70E 2021
New
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…you might have a bad maintenance condition
What’s new in NFPA 70E 2021
New
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…you might have a bad maintenance condition What’s new in NFPA 70E 2021
Table 130.5(C) Estimate of the Likelihood of Occurrence of an Arc Flash Incident for AC and DC Systems: A new task was added as YES for likelihood of an arc flash incident for any condition. “Operation of a CB or switch the first time after installation or completion of maintenance in the equipment.”78
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What’s new in NFPA 70E 2021
130.5(G) Incident Energy Analysis Method: Informational Note (e) NEW“The arc rating of outer layers worn over arc-rated clothing as protection from the elements or for other safety purposes, and that are not used as part of a layered system, shall not be required to be equal to or greater than the estimated incident energy exposure.”
Note (d) Footwear other than leather may be used if tested…
79Layered system: shirt, pants, and coveralls 40.9 cal/cm²
FR Vest (OK)
What’s new in NFPA 70E 2021
130.7(C)(1) Personal and Other Protective Equipment (C)(1) General: An informational note was added regarding examples of risk-reduction methods that could be used when testing for absence of voltage when the estimated incident energy exposure is greater than the arc rating of commercially available arc-rated PPE.
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What’s new in NFPA 70E 2021
130.7(C)(1) Examples of Risk Reduction Methods Use a non-contact tester before using a
contact test instrument to verify the absence of voltage below 1000 volts.
If the equipment design allows, observe visible gaps between conductors and circuit parts and electrical sources of supply.
Increase working distance.
Table 130.7(C)(7)(a) Maximum Use Voltage for Rubber Insulating Gloves
What’s new in NFPA 70E 2021
What’s new in NFPA 70E 2021
Article 360 Safety-Related Requirements for Capacitors:
360.1 Scope 360.2 Definitions
360.3 Stored Energy Hazard Thresholds
360.4 Specific Measures for Personnel Safety
360.5 Establishing an Electrically Safe Work Condition for a Capacitor(s)
360.6 Grounding Sticks83
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Informational Annex D.4 IEEE 1584-2018 Calculation Method: This was updated to provide an overview of the new 2018 edition of IEEE 1584.
Annex D: Calculations gone and now references IEEE 1584 std.
What’s new in NFPA 70E 2021
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Informative Annex F.7 Battery Risk Assessment: New annex material provides guidance for users on how to select PPE using a battery risk assessment process when multiple hazards are present.
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What’s New in the 2021 NFPA 70E?
Informative Annex R Working with Capacitors: This new annex provides additional information regarding capacitors to support the new Section 360.
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What’s New in the 2021 NFPA 70E?
Informative Annex R Working with Capacitors: Qualifications and Training
Shock Hazard
Short Circuit Hazard
Internal Rupture
Perform Risk Assessment
Capacitor Stored Energy
Arc Flash Hazard
Determine Arc Blast
Test and Ground Methods87
What’s New in the 2021 NFPA 70E? Can we now…
Explain Electrical Hazards Including Shock and Arc Flash.
Describe Approach Boundaries: Restricted, Limited, Arc Flash Protection Boundaries.
Define Training and Qualifications for Electrical Workers.
Demonstrate Personal Protective Equipment.
Describe Safety-Related Work Practices including methods to De-energize, LOTO and Verify by Testing.
Understand Wiring Requirements.
Explain updates to the 2021 NFPA 70E
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None of us can control the wind, but we all can control the sails.
Choose to be safe!
Questions?Email:Lee@workplacesafetysolutions.com
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