1ELC 119R-S

ELC 119R-SElectrical Safety Refresher for Subcontract Electrical

Workers

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OutlineIntroduction

1 Shock and Arc Flash

2 Electrical Hazard Mitigation

3 Technical work documentation (TWD)

4 Safe switching procedures

5 Wrap-Up

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Introduction ~ 300 workplace electrocutions annually Estimated 20,000 shocks for every electrocution ~ 4000 injuries annually requiring days away ~3600 disabling electrical contact injuries

annually 10-15 workers hospitalized daily with electrical

burns 4-year average of 23 electrical events at SNL

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Most Common Electrical Events at SNL

Short circuit of energized parts to ground Workers shocked from approaching nearer

than a safe distance from exposed live parts

Workers shocked from faulty equipment Workers shocked from

plugging/unplugging equipment

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Module 1: Shock and Arc Flash

The passage of electric current through the

body from contact with an electric circuit (conductors).

Exposure to electrical energy may result in no injury

at all or may result in devastating damage or death.

Electrocution is death by electrical energy resulting

from the passing of a high magnitude electric current

through the body

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Why Are We Susceptible to Injury by Electric Shock?

A. Our highly developed nervous system makes us extremely sensitive to even very small electric currents.

B. The passage of current through the body results in heating of tissue

Each of these interactions has serious

consequences.

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Effects of Current on the BodyCurrent Value Effects

< 1 ma Barely Perceptible

1-5 ma Perceptible shock, reflex actions

5 ma GFCI trips Accepted as maximum harmless current

6-10 ma Painful shock, victim can “let-go”

10-20 ma Painful shock, victim can not let go

50-100 ma Ventricular Fibrillation possible

100-200 ma Ventricular Fibrillation likely

200 ma Severe burns, severe muscular contractions, chest muscles clamp the heart and stop it for the duration of the shock.

833 ma Current used by 100 watt light bulb

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Effect of Current Passing Through the Body

Current can confuse or damage nerve control centers of lungs and heart

Heat damage caused by dissipation of energy- body acts as a resistor.

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Unfortunate mouse suffers a fatal phase to phase shock

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Factors Affecting Shock Remember Ohm’s Law: E=IR

Current: most important factor, though directly determined by voltage and body resistance.

Path of current: greater chance for survival if current passes through extremities only

Duration of Shock: according to IEEE std. 80, the maximum safe duration can be determined by using: t (seconds) = .116/(V/R)

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ExampleIf an electrician gets a shock from a 277 volt light fixture, would he/she get “stuck” on the circuit? Let’s assume the worker was sweating and use a resistance value of 10,000 ohms.

I =E/R

I = 277/10,000

I = .0277 amps or ~28 ma

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Is He/She Stuck?Current Value Effects

<1 ma Barely Perceptible

1-5 ma Perceptible shock, reflex actions

5 ma GFCI trips Accepted as maximum harmless current

6-10 ma Painful shock, victim can “let-go”

10-20 ma Painful shock, victim can not let go

50-100 ma Ventricular Fibrillation likely

100-200 ma Ventricular Fibrillation occurs

200 ma Severe burns, severe muscular contractions, chest muscles clamp the heart and stop it for the duration of the shock.

833 ma Current used by 100 watt light bulb

YES!

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Example continued

Let’s also assume that the path of the current is hand to hand. How long does this person have before the shock could be considered fatal?

T = .116/(V/R)T = .116/(277/10,000)T = .116/.0277T = 4.18 seconds!

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Voltage Thresholds

OSHA set threshold for hazardous energy at 50 volts

Hazard from applications lower than 50 are usually thermal not shock: batteries, super capacitors, etc.

At levels greater than 600 V, skin is usually penetrated driving resistance down.

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Entry and exit wounds

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Rescuing and TreatmentStep 1 – Check to see that the area is safe to enter

Step 2 - Call 911 immediately

Step 3- Rescue the victim with an insulated device (hot stick, rope, dry wood, etc)

Step 4 – Begin CPR

Step 5 - Continue resuscitation

Step 6 - Get medical attention for the victim

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II Arc FlashA release of thermal energy from an electric arc

by the vaporization and ionization of materials,

reaching temperatures up to 35,000 °F.

Exposure to these extreme temperatures both

burns the skin directly and causes ignition of

clothing.

(2004 NFPA 70E)

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Nature of the Arc Arc results from passing of current through air Terminals vaporize and serve as conductive medium

for ionized gasses Flash can extend further than 10’ from the source Pressure wave caused by rapid expansion of gases

with flying molten materials and shrapnel The blast can destroy structures, and knock workers

from ladders or across a room. The blast can rupture eardrums and collapse lungs.

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Nature of the Arc continued

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Three Factors Affecting Arc Energy

Available short circuit current Duration of the arc Distance from the arc

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Burns From the Arc

First degree: surface only. Skin is usually red and tender

Second degree: blistering of the skin. Most painful

Third degree: complete destruction of the skin with charring of tissue. Most dangerous –susceptible to infection. Skin can not heal itself.

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First Degree Burns from a 480 Fault

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Second Degree Burns from the same 480 Fault

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Effects of the Arc- Burns

Burn Injury - Probability of Survival

0%

20%

40%

60%

80%

100%

20-29.9 30-39.9 40-49.9 50-59.9

Age Range - Years

% S

urv

ival 25% Body Burn

50% Body Burn

75% Body Burn

Arcs have ignited clothing 10’ from the arc and can be fatal when within a few feet

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Accelerator Flash Incident

On October 11, 2004, at approximately 11:15 am,a subcontractor electrician working at an Accelerator Center received

serious burn injuries requiring hospitalization dueto an electrical arc flash that occurred during theinstallation of a circuit breaker in an energized

480-Volt (V) electrical panel.

27ELC 119R-SArc flash 2004

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Importance of FR Clothing60/40 blend here

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From the Type A Investigation…

Description of Injuries:

Electrician received third degree burns on the face, chest, and legs and second degree burns on the arms, involving approximately 50% of his body. Because of the seriousness of his condition, the Board was not able to interview him.

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Module 2: Electrical Hazard Mitigation

1. Plan your work

2. Analyze/identify the hazards

3. Control the hazards

4. Perform the work

5. Improve the process for the next operation

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1910 CFR 851 and NFPA 70E All Department of Energy Facilities are

contractually required by law follow 10 CFR 851- Worker Safety and Health Protection Plan

851.23(a)(14) requires contractors to comply with NFPA 70E as a baseline.

70E is the industry standard for addressing electrical hazards in the workplace

Applying 70E standards nothing more than using integrated safety management

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TURN IT OFF! Energized work no longer allowed at SNL

unless:“de-energizing introduces additional or increased

hazards or is infeasible due to equipment design or operational limitations” 70E 110.8.A.1

Most hazards can be controlled by insulating,

guarding, or by simply working de-energized

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Electrically Safe Work ConditionFirst priority is to de-energize1. Review safety plan

2. Inspect equipment, disconnect energy sources, and lock and tag energy sources.

3. Post barricades and signs to establish the limited approach and flash protection boundaries.

4. Open enclosure, identify shorting devices, and discharge energy-storage devices if applicable.

5. Perform Zero Energy verification Test

6. Complete work

7. When the work is completed, test circuits, remove tools, and test gear, perform final check, and close enclosure

NOTE: Equipment is not considered de-energized until locked out and verified

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Energized Work - provided justification requirements (slide 34) are met

Strict requirements addressing worker qualifications: Qualified Person: One who has the skills and knowledge related to

the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved (Electrical Safety in the Workplace, 2004).

Energized work must be authorized by Senior Manager Facilities Engineering- see your contract Sandia delegated representative (SDR)

Shock and Flash Hazard Analyses required. This can be accomplished using the table on slide 44. Remember 2 different hazards- shock and flash

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Shock Hazard Analysis Required ANYTIME a worker crosses the

Limited Approach Boundary to exposed live parts

Must determine approach boundaries (Limited and Restricted) and required shock PPE (usually gloves and insulated tools)

Shock PPE required ANYTIME a worker crosses the Restricted Approach Boundary

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Shock Approach Boundaries

Limited Approach Boundary (LAB) Level II authorization required Only qualified workers may cross * Boundary must be physically established

Restricted Approach Boundary (RAB) No unqualified workers Shock PPE required Shock PPE mainly consists of insulating gloves and tools

Refer to slide 44 for LAB and RAB approach distances and required PPE.

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Flash Hazard Analysis

Required ANYTIME a worker crosses the flash protection boundary (FPB)

Must determine the Flash Protection Boundary and the PPE required for crossing this boundary

PPE and distances determined from table slide 44

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Arc Flash Protection• PPE and flash protection boundary (FPB) in

CSSP will match that of arc flash hazard (AFH) label on equipment

• If the electrical equipment is not provided with an AFH warning label, PPE and FPB in CSSP will be determined using the table in slide 44.

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Exposed Live PartLimited Approach Boundary (shock)Level II authorization requiredOnly qualified workers may cross – unqualified workers may cross if escorted by qualified worker and made aware of the hazards Boundary must be physically established

Flash Protection Boundary Distance and PPE determined from table in slide 42PPE required of ANYONE inside this boundary

Restricted Approach Boundary (shock)No unqualified workersShock PPE requiredShock PPE mainly consists of insulating gloves and tools

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Hazard Risk Categories (HRC)

HRC 0: Single phase circuits operating at 50-208 volts HRC 1&2: Three-phase circuits operating between 120

and 600 volts HRC 3&4: Three-phase service entrance equipment and

switchgear operating between 120 and 600 volts, excluding those systems with a RED, Level V Arc Flash Hazard label.

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Hazard Risk Categories (HRC)

Hazard Risk Above Forty Calories: All equipment identified with a Level V (red) Arc Flash Hazard label

Hazard Risk Greater Than 600 volts: Obtain flash hazard analysis. Exception: HRC 2 PPE shall be worn In 15 kV

manholes. Head, face and glove protection may be removed during cable terminations if no other work is being performed in the manhole.

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Boundary and PPE TableEquipment Class

HRC

Flash Boundary

LAB, RAB

Required flash PP

Required shock PPE

PPE Code

208/240 1-ø 04’

3’ – 6”, contact

EWC

Class 0 gloves with leather protectors and insulated tools

Green

120/240, 277/480

3-ø non service entrance

1, 26’

4’, 1’

EWC + accessories

Class 0 gloves with leather protectors and insulated tools

Blue

120/240, 277/480

3-ø service entrance3

Contact FMOC project lead

4’, 1’

ISC

Class 0 gloves with leather protectors and insulated tools

Yellow

120/240, 277/480

3-ø service entrance4

Contact FMOC project lead

4’, 1’

ESC

Class 0 gloves with leather protectors and insulated tools

Orange

Equipment labeled greater than 40

calories or 600 voltsNA

Contact SDR, CO, or PM for assistance

Contact SDR, CO, or PM for assistance

Red

EWC: FR long sleeve shirt (min arc rating = 8) worn over untreated cotton t-shirt with FR pants (min arc rating = 11, safety glassesAccessories: hard hat w/FR rated face shield, hearing protection, and leather boots or shoesIWC: EWC + accessories + FR coveralls (min arc rating = 25) and double –layer switching hood.ESC: 40-calorie switching suit w/rated hood and gloves, leather boots and shoes.

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Example Arc Flash Labels Level I (HC-0) Label Level II (HC-1 and HC-2)

Label WARNING ARC FLASH & SHOCK HAZARD

BUILDING 752 LOCATION PANEL 1BH1

INCIDENT ENERGY @ 18”

6.9 cal/cm2 HAZARD

CATEGORY 2

APPROACH BOUNDARY 3.8 ft PPE LEVEL II

SOURCE TF-0752-1 MAXIMO

DATE 10/05/07

WARNING ARC FLASH & SHOCK HAZARD

BUILDING 867 LOCATION PANEL MSB1

INCIDENT ENERGY @ 18”

< 2 cal/cm2 HAZARD

CATEGORY 0

APPROACH BOUNDARY 3 ft PPE LEVEL I

SOURCE TF-0867-1 MAXIMO

DATE 10/05/07

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Electro-Magnetic Energy Whenever you have electric power, electric and

magnetic fields will be generated. The electric field is often generated by the

alternating voltage of the electrical system. The higher the voltage, the greater the electric field. Taken together, electric and magnetic fields are often referred to as electromagnetic radiation.

The main effect of exposure to EME is heating of tissue and organs.

There are rooftop antennas at Sandia that emit varying levels of EME so contact your ES&H coordinator before approaching them

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Worker Responsibilities Familiarize yourself with procedures and

work plans- CSSP Be aware of your surroundings Obey all warnings signs and regulations Always use proper PPE (slide 44) Stop work if an unsafe and/or unexpected

condition arises Consider ALL electrical equipment energized

unless locked out and verified de-energized

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Worker Responsibilities• Do NOT perform unjustified energized work• Do not wear jewelry when performing energized

work• Report ALL accidents, regardless of severity to

Safety Officer/Supervisor• Immediately report to your supervisor, anyone

known to be under the influence of drugs or alcohol

• Be aware of secondary hazards- beryllium, radiation, noise, etc

• Be responsible for your own safety!

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Planning Your Work Planning is a key element in performing work safely

and is the first step in the ISMS process. OSHA and 70E require a job briefing be held before

any electrical work operation begins. All personnel involved in the job shall be briefed on the

safety concerns, energy source controls and precautions regarding their assignments.

Should work conditions change or unanticipated hazards appear, additional briefings should be held.

Planning must be documented!

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Planning Your Work continued

Consider ALL hazardsWhen changing a ballast, what hazards are

involved besides electricity and working from heights?

Is there an asbestos issue? Is the fixture in an area known to have

dangerous levels of Beryllium?How about radiation?

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Planning Your Work continued

• The meeting must cover the following questions:– Do I thoroughly understand the job?– Do I thoroughly understand my role in the job?– Am I aware of all the hazards I may encounter?– Am I knowledgeable of all the safety rules and

required personal protective equipment that apply to the job?

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Performing Your Work All circuits must be considered energized until

LOTO’d and verified de-energized Several events at SNL have been the result of failure to

verify de-energized Performance of the 0 energy verification still

requires PPE and boundary establishment (slide 44)

Do you have to do this hot? Physically establish the limited approach boundary

(slide 44) Boundary must keep unqualified workers out of area Boundary must warn workers of the hazards inside the

area

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Performing Your Work Wear the appropriate PPE

Shirt must be buttoned and sleeves rolled down Flash PPE is required when inside the flash protection boundary (slide 44)

Crossing the restricted approach boundary requires gloves and insulated tools (slide 44) Maintain your gloves Are they out of testing date requirements?

Use the right tools for the job Is you meter rated for the task? Several events at SNL have occurred due to use of an inappropriate meter

Do not deviate from job plan. If work outside of scope is required stop and re-evaluate with all involved

co-workers.

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Module 2 Conclusion Severe hazards associated with energized electrical work Energized work is now the exception- not the norm- Turn

–it-off! NFPA 70E provides sound guidance for electrical safety

in the workplace Applying the standard is basic ISMS- identify the hazard,

control the hazard Remember there are two primary hazards (shock and

flash) that must be analyzed and controlled independently

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Module 3: TWD RequirementsQ: What is considered energized work at SNL? A: Any activity inside the Limited Approach

Boundary (LAB) Crossing the LAB for ANY reason must meet

the 70E justification requirements of 110.8.A.1 (slide 35)

ALL energized work requires a technical work document

Why? This should be your first question when asked to work energized.

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Contract Specific Safety Plan (CSSP)

The CSSP is the required technical work document for all energized work at SNL performed by a facilities subcontractor

The CSSP must incorporate the required energized work permit elements required in NFPA 70E 130.1B2

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Content of the CSSP1. A description of the circuit/part to be worked on and its

location

2. Justification of why the work must be performed energized. Remember that some troubleshooting could be accomplished with an Ohm meter.

3. A description of safe work practices to be employed (second person, safety watch, Barriers, etc)

4. Results of the shock hazard analysis (voltage the employee(s) will be exposed to) – slide 44

5. Determination of shock approach boundaries (LAB, RAB, PAB) using table slide 44

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Content of the CSSP continued

6. Results of the flash hazard analysis (determination of the Flash Protection Boundary and the caloric exposure based on table slide 44

7. The necessary personal protective equipment- shock and flash

8. Means used to restrict access of unqualified personnel to the area (chains, flagging, signage, etc)

9. Evidence of completion of a pre-job briefing including topics covered- checklist

10. Energized work approvals (workers, Managers, Senior Managers)

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Insulated Tools Insulated tools, rated for the system voltage, are

required when contacting any energized component. Insulated tools should be listed under # 3. Ground hooks shall also be listed here.

  If the insulated tool can prevent the user from

crossing the restricted approach boundary and flash protection boundary, PPE will not be required (except safety glasses).

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Module 4 Safe Switching Procedures

Three hazards associated with switching breakers or disconnectsShockExplosionArc flash/blast

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Shock

Rare when switching because cover should be in place.

Remember shock boundaries 30,000 non-fatal shocks each year in the

workplace… 247 died from electrocution in 2006…

down from 251 in 2005.

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Breaker Explosion

Counterfeit Products Sub-standard

components No NRTL listing

Improper Sizing Improperly rated for

available fault current

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Arc Flash - 2006

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Operating Breakers and Disconnects

Use one hand when possible. For side-handled switches, stand as far away

to the side as possible to operate the switch. For panel-mounted breakers, do not stand in

front of the panel when operating the breaker. Do not expose unprotected portions of the

body/face to the potential blast.

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Review – Switching OperationsDisconnect Rating Required PPE (Hazard

Category)Up to and including 60 amps (< 600 volts)

HC 0 *

>60 up to and including 200 amps (< 600 volts)

HC 2 *

> 200 amps (< 600 volts) and all > 600 volts

Must be analyzed by a qualified person. Contact

electrical safety for evaluation.

•Arc flash labels supersede this table

•reference slide 44 for specifics

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Module 4 Conclusion Switching can be hazardous Wear appropriate PPE Obtain AIC and clearing times prior to switching Never switch breakers or disconnects under trip

conditions - call facilities Never close a breaker or disconnect if uncomfortable Use Left hand rule to keep body away from

disconnect when closing

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Course Wrap-Up You seldom get a second chance with electricity Most electrical accidents are caused by unseen or

unanticipated hazards Take your time! Never deviate from procedures If circumstances or conditions change- STOP and

re-evaluate Work on energized equipment is restricted at SNL Maintain tools, test equipment, and PPE Never rely on others for your safety

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Thanks for Viewing

Questions:Greg Kirsch at 845-9497

Mark McNellis at 845-4895 Marc Williams at 845-8795