NFPA 70E Electrical Safety in the Workplace

KTR AssociatesEngineering Solutions Joseph Deane, PE

Goal for Today

Better understanding of NFPA 70ERaise the awareness of Electrical HazardsWhy the sudden focusWhat one must do to become “70E”compliant

Topics To Be Discussed

Define Electrical HazardsSafety NumbersIndustry Standards/Government RegulationsWhat is an Arc Flash?Sample Arc Flash StudyPPE Requirements

Why do we need Electrical Safety?

Provide a safe work environmentReduce injuriesComply with regulationsReduce liabilityReduce operating costs

What are the Electric Hazards?

ShockArc FlashArc Blast

Terms and Definitions

• Electric Shock (Contact): Occurs when electricity (electric current) passes through the human body. Electric current passing through the chest area may result in death.

Terms and Definitions

Arc Flash: Short circuit through air; defined as the rapid release of energy due to an arcing fault between two phase conductors (such as bus bar) or neutral or ground.

Arc Blast: Heating of the air and vaporization of metal creates a pressure wave than can damage hearing and other injuries. Flying metal parts are a hazard.

Terms and Definitions

Incident Energy: Energy dissipated during an arc fault, or arc flash event. Measured in cal/cm2 .Arc Thermal Performance Value (ATPV): Minimum energy causing the predicted onset of second degree burns. A second degree burn is 1.2 cal/cm2 .

Why the Recent Focus?

NFPA 70E standard now recognizes Arc Flash as a serious consequence and requires a Flash Hazard analysis be performed on facilities.OSHA has updated its Electrical Safety Procedures for the first time in 25 years.Effective date of OSHA’s updated regulations is August 13, 2007

Electrical Statistics

At least one person a day is electrocuted in the workplace everyday

Over half of the deaths are from working “live”electrical circuits less than 600 volts.

Average of 4000 non-disabling and 3600 disabling electrical injuries occur in the US.

Electrocutions by Year (Construction Safety Council)

474440

480 486

395

544

664

0

100

200

300

400

500

600

700

1992 1994 1996 1998

# Electrocutions

Electrical Statistics

Five to 10 arc flash explosions occur in electrical equipment every day in the US.

Fourth leading cause of occupational fatalities.

Over 2000 workers are admitted to burn centers each year.

Burn Costs

Average burn case costs $12 to $20 Million

Average hospital burn unit costs $400K per month

Average hospital burn unit stay 3 months

Electrical Statistics

General IndustryOne fatality per 300 recordable injuries.

Electrical IndustryOne fatality per 10 recordable injuries.

Electrician Survey

97% had experienced an electrical shock. 26% had witnessed an injury.58% were exposed to the possibility of an injury every day.

Facts on Electrical Incidents

80% of electrically related accidents and fatalities among Qualified Workers are caused by Arc Flash.80% of electrically related accidents and fatalities among Unqualified Workers are caused by Electrocutions.Age 34 is the median age for someone killed working around electricity.

OSHA & NFPA 70E

OSHA was created in 1969. It incorporated the National Electric Code (NFPA 70 standard 1971) into its electrical standard.

NFPA 70E Standard was created at the request of OSHA in 1979 to recognize the difference between design and workplace safety.

NFPA 70 (NEC) applies to installations (design).NFPA 70E addresses workplace safety.

OSHA Regulations

OSHA bases its electrical safety mandates on:

CFR 1910 Subpart S (General Industry)CFR 1926 Subpart K (Construction)

OSHA recognizes NEC and NFPA 70E as an industry standards.

OSHA Regulations

OSHA requires companies to follow its regulations and will cite companies for non-compliance under the General Duty Clause:

which states, “each employer shall furnish to each of its employees a place of employment that is free from recognized hazards that are likely to cause death or serious physical harm.”

OSHA Regulations

OSHA is also citing companies for the following:

29 CFR 1910.335 (a)(1)(i): requires the use of protective equipment when working where a potential electrical hazard exists.29 CFR 1910.132 (d)(1): requires an employer assessment of all workplace hazards and the use of personal protective equipment.

Who is the NFPA?

The National Fire Protection Association (NFPA) develops, publishes, and disseminates more than 300 consensus codes and standards intended to minimize the possibility and effects of fire and other risks.Virtually every building, process, service, design, and installation in society is affected by the NFPA documentation (Ex. the National Electric Code…NFPA 70).

National Electric Code (NFPA 70)

Utilized for design and installation of electric facilities

Wiring and ProtectionWiring Methods and MaterialEquipment for General UseSpecial Equipment and Conditions

Intent of NFPA 70E

Objective is to minimize exposure to electrical hazards for personnel working around electricity. This includes:

ElectriciansMechanicsHVAC techniciansPaintersPlumbersCarpentersProduction Workers

Intent of NFPA 70E

Define Safe Work Practices to avoid injury.Define the requirements for an Electrical Safety Program.Define the requirements for TrainingDefine the requirements for PPE Applies to all types of employers and facilities, including employees, contractors, and construction workplaces.

NFPA 70E Electrical Safety Standard in the Workplace

Chapter 1 – Safety Related Work PracticesChapter 2 – Safety Related Maintenance RequirementsChapter 3 – Safety Requirements for Special EquipmentChapter 4 – NEC Related Installation Material

NFPA 70E covers…

Public and private buildingsCarnivalsIndustrial SubstationsAny installation of electrical equipment to the supply of electricity

NFPA 70E does not cover…

UtilitiesShipsMinesRailwaysCommunication equipment under control of communication utilities

NFPA 70E Chapter 1

Article 110 – Provides General RequirementsResponsibilityElectrical Hazard AnalysisTraining RequirementsElectrical Safety Program

Article 120 – Emphasizes Working De- energized & Describes the Work PracticesArticle 130 – Provides Requirements for Working On or Near Electrical Components

Chapter 1 Responsibility

Employers are responsible for providing work practices and procedures.Employees are responsible for implementing them.

Chapter 1 Multiemployer Relationship

Recognizes that more than one employer may be responsible for hazardous conditions on a worksite.Outside contractors are contractually obligated to the onsite employer.Both employers must share their Electrical Safety Programs with each other.

Chapter 1 Multiemployer Relationship

Onsite employers and outside contractors shall inform each other:

Of existing hazardsPPE requirementsSafe work practice proceduresEmergency procedures

Coordination should include a meeting and documentation

Chapter 1 Electrical Safety Program

What needs to be in it?

ScopePhilosophyPrinciplesResponsibilitiesSafety Procedures

Chapter 1 Electrical Safety Program

PPE RequirementsControlsTraining RequirementsAuditingOther?

Chapter 1 Training Requirements

Trained to understand the specific risks associated with electric energy.Trained on safe work practices and procedures.Trained on emergency procedures.Training may be both classroom and on the job.

Training Session

Misc. Real World ExamplesRefeeding Panels (What needs to be checked?)Transformer Connections (Why they are important)Types of Grounding SystemsExplain how voltage is a difference in potential

Chapter 1 Electrical Hazard Analysis

Requires an electrical hazard analysis, which is a study of a worker’s potential exposure to:

ShockArc Flash/Blast

It determines the appropriate levels of Personal Protective Equipment (PPE) and work practices.

Electric Shock

The original purpose of NFPA 70EDetermine the voltage to which personnel will be exposed.Boundary RequirementsPPE Requirements

Exposure to Shock

Requires exposure to a difference of potentialThe National Electric Code reduces this risk under normal conditions.NFPA 70E reduces the risk under abnormal conditions

NEC Protects - Normal Conditions

70E Protects - Abnormal Condition

Effects of Electric Current on the Human Body

Amps < 1 mA Barely perceptible

5 - 10 mA Tingling sensation (annoying)

10 - 20 mA “Let Go” threshold (discomfort)

20 – 50 mA Painful, cannot “Let Go”

50 - 100 mA Ventricular fibrillation

Amps > 100 mA Cardiac arrest

Electric current greater than the “Let Go” threshold ( current > 20 mA) contracts the human body’s muscles. Individuals unable to “Let Go” an energized line face life threatening damage to their bodies. If this current level continues for an extended period of time, respiratory paralysis is possible. Ventricular fibrillation (uneven pumping of the heart) causes death to lack of oxygen to the brain.

Effects of Electric Current on the Human Body

Arc Flash/Blast

Electrical Arc between ConductorsIntense LightMolten MetalPressure WaveSound WaveShrapnelHot Air Rapid Expansion

Dangers of Arc Flash

Arcs in enclosures, such as MCCs and switchgear, magnify a blast outward as energy is transmitted to the open side of the enclosure.Fatal Burns (Molten metal at high speed pressure).Falls from ladders (Blast pressure waves).

Hearing loss from sound blast.

Causes of Arc Flash

ContaminationDust, Dirt or VaporCorrosionMoisture Ingress

Dropping tools or equipmentInsulation Breakdown/AgingNarrow Gaps

NFPA 70E Arc Flash Hazard Analysis

A flash hazard analysis shall be done for two purposes:

Determine the arc flash protection boundary.Determine the proper PPE (rating of flame retardant clothing).

The Flash Protection Boundary is the approach limit from which a person could receive a second degree burn if an arc flash occurs.

Sample Arc Flash Study

How do you do an Arc Flash Study?

Results of an Arc Flash Study

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Performing the Arc Flash Study

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Nine Step ProcessCollect system and installation dataDetermine system mode of operationDetermine bolted fault currentsDetermine arc fault currentsFind protective device characteristics and arc duration

IEEE 1584 Standard – Guide for Performing Arc Flash Hazard Calculations

Nine Step Process (continued)Document system voltages and equipment classSelect working distancesCalculate the incident energyCalculate the Flash Protection Boundary

From this info, select the proper PPE

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Purpose of Safety Related Work Practices (Article 120)

A set of rules that ensure an Electrically Safe Work Condition.De-energizing is safest work condition.Protect employees from:

ShockArc Flash burnsArc Blast injuries

Steps to Create an Electrically Safe Work Condition (De-energized state)

Check drawings and identify all possible sourcesInterrupt load current and open disconnectsVisually verify opening of contacts where possibleApply lockout/tagout devices according to policyTest voltage and verify operation of testerApply grounds where necessary

Working on or near energized circuits (Article 130)

Why work on energized circuits?

Examples of working on energized equipment

Startup or troubleshootingLife Support systemsEmergency systemsVentilation systems for hazardous locations

Examples of working on energized equipment

Infeasibility due to equipment design or operational limitations Circuits that are part of integral process.

NFPA 70E Requirements for Working on or Near Live Parts

Complete Energized Electrical Work PermitPerform Hazard/Risk AnalysisSelect PPEEnsure task specific trainingConduct a job briefing

Energized Electrical Work Permit

Requires written authorizationRequires the worker to:

Identify and understand the hazardsBe a qualified personWear proper PPERestrict access to unqualified personsComplete a job briefing

No Permit Required When…

Testing (voltage, current, phasing)TroubleshootingCircuit Identification

Approach Distances to Exposed Live Parts

PPE Requirements

Protect against shock and burnsDesigned to protect specific areas of the body:

Head, face, neckEar protectionEye protectionBody protectionHand and arm protectionFoot and leg protection

Flash Protection Boundary & PPE

When working within the flash protection boundary, PPE must be worn.PPE is determined by the level of incident energy exposure.

Personal Protective Equipment (PPE)

Flash Hazard

Risk Category

Range of Calculated

incident energy

Min. PPE Rating Clothing Required

0 0 to 1.2 cal/cm2

N/A Untreated cotton

1 1.2+ to 4 cal/cm2

4 cal/cm2 FR shirt and pants

2 4+ to 8 cal/cm2

8 cal/cm2 Cotton underwear plus FR shirt and pants

3 8+ to 25 cal/cm2

25 cal/cm2 Cotton underwear plus FR shirt and pants plus FR

coveralls

4 25+ to 40 cal/cm2

40 cal/cm2 Cotton underwear plus FR shirt, pants, plus multilayer layer flash

suit

Personal Protective Equipment (PPE)

Category 0 (Min. PPE Arc Rating N/A)Untreated CottonSafety Glasses

Category 1 (Min. PPE Arc Rating 4)Long Sleeve FR Shirt & PantsHard HatSafety GlassesLeather Gloves & Shoes

Personal Protective Equipment (PPE)

Category 2 (Min. PPE Arc Rating 8)Cotton UnderwearFR Shirt & PantsArc Rated Face ShieldSafety GlassesHearing ProtectionLeather Gloves & Shoes

Category 3 (Min. PPE Arc Rating 25)Same as Cat 2 but include FR coveralls & Flash Suit Hood

Personal Protective Equipment (PPE)

Category 4 (Min. PPE Arc Rating 40)Cotton UnderwearFR Shirt & PantsFull Flash Suit & HoodHearing ProtectionLeather Gloves & Shoes

Labeling

NEC Article 110.16 requires arc flash labeling in electrical enclosures that might be maintained and accessed while energized.Switchboards, panelboards, industrial control panels, MCCs, etc.

Arc Flash Labeling

Warning Label Examples

Recent Example of Arc Flash Incident

Electrician using multimeter shorted out resulting in three phase arc flash.Gloves and radiological PPE were melted and he suffered minor burns.Test equipment defective (CEN-TECH Digital Multimeter). No certification from a national testing laboratory.

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Sample Electrical Power Design

• Maintenance Mode Switch (utilizing Microprocessor- based Protective Relays Alternate Settings)

• Control cabinet containing switches to close breakers

What must I do to become NFPA 70E compliant?

Conduct an Arc Flash hazard analysis.Provide labeling on electrical equipment per NEC article 110.16 “Flash Protection”.Document your Electrical Safety Program.Provide training to your employees.Provide the proper tools and PPE for job tasks employee would be performing.

Other Issues to Think About

Determine Qualified vs Un-QualifiedWho’s permitted to reset CBs? Anyone?Which methodology should I use for calculating incident energy?

NPFA 70EIEEE 1584

Energized Work Permit…when do I need this?Circuit Breaker Interrupting RatingsWhen do I apply OSHA 1910.269?

Don’t Learn Safety by Accident

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Don’t Learn Safety by Accident

Stop ! Think ! Then Act !NFPA 70E is your guide for

Electrical Safety in the Workplace

Questions

Thank-you for your interest!