We specialize in Water Towers Industrial Tanks & Logos
High Rise Buildings - Chemical Plants - Factories . Casinos -  Office Structures - Theme Parks
Structural Steel -   Industrial Pipes  - Silos - More

1 - 877-749-5554    pat@greatwesternpainting.com


 
*
Home
Contact

Acrylic Texture
Anti GraffitiArizona
Arizona Tank Painting
Bad Paints & Effects 
Business Friends
California Tank Painting
Casinos
Clarifier Tank Painting
Custom Car Painting
Electrostatic Painting
Factory Painting
Fire Proof Painting
Free Gifts
High Rises
Grain Elavators
Hospital Painting
Ind. Paint Manufactures
Industrial Pipe Painting
Industrial Tanks
Lead Encapsulation
Light Pole Painting
Luminescent Paint
Montana Tank Painting
MSHA Certified
North Dakota Tank
Paint Dealers
Safety  & Fall Program
Sand & Hydro Blasting
Shale Gas Fraking
Shot Blasting
Silo painting
Site Map
Structural Steel Painting
Surge Tank Painting
Tank Painting
Texas Tank Painting
Thermal Painting
Utah Tank Painting
Vinyl Wall Covering
Water Tank Inspections
Water Towers


















































































































































































































































































































































































































































































































































 

Back To Safety Programs            Home

 

Electrical Arc Flash Hazard Protection Program

How does an Electrical Ac Flash happen?

An electrical Arc, simply defined, is electrical current passing through air. Dry air is normally a very good insulator and will not conduct
 until the voltage exceeds 75,000 volts per inch. In most cases, during an arc the current is actually passing through a mixture of ionized air and vaporized conductor.

Most electrical arcs occur as a result of a short circuit. Let’s say an electrician accidentally gets a pair of pliers across the conductors in a
motor circuit. Because the pliers present a much lower resistance than the motor, a very large current will flow. The only limit to the amount of current that will flow is the ability of the power source to provide current and the resistance of the conductors and the pliers.

Scope and Purpose of the Electrical Arc Flash Hazard Protection Standard

The Electrical Arc Flash Hazard Protection Standard mandates the minimum safety rules, design criteria and practices for personnel working within the Electrical Arc Flash Hazard Boundary of electrical systems operating at greater than 50 volts, Ac or DC, 50 to 60 Hertz. The standard applies to all Your Company’s-owned, Your Company’s-managed, and Your Company’s-leased facilities worldwide, and to all Your Company’s personnel, contractors, subcontractors, vendors, and visitors.

Personnel working within or around and Electrical Arc Flash Hazard Boundary shall know, understand and follow the safe work practices contained within the standard.

In addition, location personnel shall follow local legislative codes or accepted employee safety standards, design criteria, etc., when they are more stringent than those identified in the Electrical Arc Flash Hazard Protection standard.

The purpose of the Electrical Arc Flash Hazard Protection standard is to eliminate injury to Your Company’s personnel, contractors, subcontractors, vendors, and visitors caused by Electrical Arc Flash Hazards.

Each location shall perform an Arc Flash Hazard Assessment to determine if Arc Flash Hazards exist.

Definitions

Arc Fault Current

For Arc Flash Hazard Analysis calculations, use the short circuit symmetrical amperes from a bolted 3-phase fault. Select the value at time of circuit interruption.

Arc Flash Hazard

Danger due to Arc thermal energy from an electric arc fault.

Arc Flash Hazard Analysis

Calculations to predict the Arc thermal energy from the source of an electric arc fault.

Arc Flash Hazard Assessment

A process to determine if an Arc Flash Hazard exists.

Arc In A Box

The estimated Arc Thermal Energy created in a six-sided metal enclosure. The Arc Flash Hazard is present due to one side open.

Arc Thermal Energy

Radiant heat intensity in calories/cm2 emitted by an electrical arc.

Arc Thermal Performance Value (ATPV)

Amount of heat energy in cal/cm2 a fabric or garment is rated to protect the wearer from a second-degree burn. (Note: The onset of a second-degree bum to the skin is 1.2 calories/cm2.)

Close Proximity

Close enough to reach, fall into, or otherwise accidentally contact an electrical source. Working in Close Proximity would be within the Electrical Arc Flash Hazard Boundary.

Electrical Arc Flash Hazard Boundary

The distance from an arc flash hazard source where Arc Thermal Energy applied to the skin is equal to 1.2 calories/cm2 which are the onset of a second-degree burn to the skin. Additional PPE is required within this area for protection from arc thermal energy.

Energy of Break Open Threshold (EBT)

Amount of heat energy in calories/cm2 a fabric or garment is rated before the garment fabric breaks open. EBT is averaged from the highest five energy values.

Flame Resistant (FR)

Material treated with a chemical flame retardant to prevent clothing ignition, or natural materials that are inherently flame resistant (e.g. wool, PR 97, Nomex).

Live Line Tools

Tools electrically rated for the voltage involved and used to touch or come in close proximity to exposed, energized conductors or equipment.

Personal Protective Equipment (PPE)

Clothing and equipment that protects the wearer from injury.

Project Manager Responsibilities

The Project Manager shall be responsible for implementing location-specific practices and a procedure that meets or exceeds those contained within this document, and for providing personnel training that incorporates such information. The Project Manager may delegate the task of implementing the requirements of this document.

Training Requirements

Arc Flash Hazards can change as distribution systems change, due to additional equipment or switching operations. Personnel exposed to Arc Flash Hazards shall be trained in:

·         Identifying potential Arc Flash Hazard tasks and locations; and

·         The safe work practices necessary to eliminate injury from an Arc Flash Hazard; and

·         The use and care of PPE.

·         Personnel exposed to Arc Flash Hazards must be initially trained and retrained at a minimum of every two years. When the Arc Flash Hazard task, or PPE requirements change, additional training is required.

Arc Flash Hazard Assessment

Locations must perform an Arc Flash Hazard Assessment to determine if Arc Flash Hazards exist. The following are the steps necessary for performing an Arc Flash Hazard Assessment:

Assess Tasks

Location Management shall ensure the tasks listed in Table 4.3.1 are assessed. If there are no tasks involving an Arc Flash Hazard, the assessment is complete. If the task is operation of enclosed switchgear with doors closed, perform an Arc Flash Hazard Analysis per Section 4.4 or use the PPE Level described in Table 4.5 to complete the assessment.

Tasks associated with an Arc Flash Hazard.

·         Inspection or infrared testing in opened panels with exposed energized bus

·         Voltage testing and phasing

·         Racking circuit breakers (open or enclosed switch ear

·         Switching

·         Grounding

·         Cleaning bushings and insulators

·         Opening doors or compartments to exposed bus

·         Using Live Line Tools/Voltage Rated Tools

·         Electrical equipment operation with doors opened

·         Operation of enclosed switch gear with doors closed

·         Performing other activities that may initiate an Arc Flash Hazard

Hazard Control

Priority must be given to eliminating the Arc Flash Hazard. Determine if equipment design or work practices will control the Arc Flash Hazard. Arc Fault rated switchgear complete with viewing windows and integral-grounding (earthing) switches is an example of equipment designed to eliminate the Arc Flash Hazard.

Examples of work practices to control Arc Flash Hazards include remote operation of switches and circuit breakers, remote grounding of switches and circuit breakers, or use of rated electrical isolation blankets or barriers. If the equipment design or work practice results in elimination of the Arc Flash Hazard, the assessment is complete.

Determine Electrical Arc Flash Hazard Boundary

When an Arc Flash Hazard is present, personnel must know the Electrical Arc Flash Hazard Boundary. The Electrical Arc Flash Hazard Boundary is the distance from the arc source at which the Arc Thermal Energy is equal to 1.2 calories/cm2. To calculate the Electrical Arc Flash Hazard Boundary, refer to Arc Hazard Assessment lesson in this Learning Guide. If the task is performed outside the Electrical Arc Flash Hazard Boundary, further analysis is not required.

Determine the Arc Thermal Energy for the task to be performed

To calculate the Arc Thermal Energy, refer to Arc Hazard Assessment lesson in this Learning Guide. If the voltage is 600 volts or greater, use software, or refer to Arc Hazard Assessment lesson in this Learning Guide. . If the task involves enclosed switchgear with doors open and the switchgear is rated greater than 600 volts, refer to Personal Protective Equipment lesson in this Learning Guide to complete the assessment.

Determine PPE

Select PPE to protect from the Arc Thermal Energy at the worker location within the Electrical Arc Flash Hazard Boundary. Refer to Personal Protective Equipment lesson in this Learning Guide to complete the assessment.

Control the Arc Flash Hazard area

Create a Safe Work Zone, refer to Create a Safe Work Zone lesson in this Learning Guide to complete the assessment..

Arc Flash Hazard Analysis

The Electrical Arc Flash Hazard Boundary and the Arc Thermal Energy to which a worker could be exposed must be calculated. The calculations for these are covered in detail in the Arc Flash Hazard Analysis section of this learning guide.

Creating a Safe Work Zone

Personnel without appropriate PPE shall not cross an Electrical Arc Flash Hazard Boundary and enter a work area where an Arc Flash Hazard is present.

To establish a. Safe Work Zone where voltages are less than 1000 volts AC, establish appropriate safe work practices to protect personnel from hazards present in the work zone. To establish a Safe Work Zone where voltages are greater than 1000 Volts AC, follow the requirements in High Voltage.1, Section 8.0. This section refers to standard Tag-Lock-Try procedures and establishment of barriers around the designated work zone. The work zone is determined by the Arc Flash Hazard boundaries and  minimum approach distances as defined in High Voltage.

Electrical personnel will normally control the boundary with equipment having signage to illustrate distances.

Personal Protective Equipment

If an Arc Flash Hazard Analysis is not performed, personnel must wear the PPE Level as described in the Personal Protective Equipment section of this learning guide.

Personnel must wear the appropriate PPE for the determined Arc Flash Hazard level. In order to protect personnel from injuries greater than second-degree bums, the PPE must reduce Arc Flash Hazard exposure to less than 1.2 cal/cm2. Refer to the Personal Protective Equipment section of this learning guide.

Care and Maintenance of PPE

PPE shall be inspected, maintained, and cared for according to the manufacturer's specifications. PPE shall be inspected before each use per the manufacturer's recommendations. Any damaged PPE shall be removed from service. PPE soiled with grease or flammable liquids shall be removed from service and property cleaned. PPE damaged in an arc flash incident shall be removed from service.

Periodic Reviews

Annual self-assessments of the location's electrical safety program shall be conducted to ensure personnel are complying with the requirements of this document, and that personnel are wearing the proper PPE to eliminate Arc Flash Hazard injuries. Action plans shall be developed to close any identified gaps.

Modifications, Changes or Additions to Electrical Systems

If modifications, changes or additions to the electrical system occur, a reassessment shall be completed to verify the Arc Flash Hazard and PPE requirements. The reassessment documentation shall include modifications completed, modified Arc Flash Hazard or PPE required, date and assessor's name.

Design of Electrical Systems to Limit Arc Flash Hazards

An Arc Flash Hazard Assessment shall be conducted on any newly designed electrical systems. Priority must be given to eliminating the Arc Flash Hazard through the appropriate engineering and design.

After January 1, 2004, new switchgear rated for 1000 volts and above must be arc fault rated with integral grounding switches and viewing windows.

 

Determining the Electrical Arc Flash Hazard Boundary

The Electrical Arc Flash Hazard Boundary is the distance from the arc source at which the Arc Thermal Energy becomes less than or equal to 1.2 calories/Cm2. The boundaries are established for the safety of the worker who must perform tasks near known arc flash hazards.

Derivation of Formulas

The formulas for calculating boundaries for safe work zones, where there is the potential for an arc flash hazard and the formulas for calculating the amount of thermal energy present as a flash occurs, are derived from several sources. The formulas have some component numbers that are constant and others that are variable. Also, they are accepted as the rule by safety agencies and by recognized experts in industry.

These calculations occur in the AES (Your Company’s Engineering Standard) Electrical Arc Flash Hazard Protection.1, and are integral elements of the AES High Voltage.1 for high voltage safe work practices and the soon to be mandated AES 32.69.1 for low voltage levels.

The primary resource for the research that went into deriving these calculations was based upon research performed by the NFPA (National Fire Protection Association) comprised of some of the industries’ leading experts in the field of electrical safety.  Other standards organizations such as the IEEE and Edison Electrical Institute had input.  Many leading industries such as DuPont, Duke Energy, and Ontario Hydro have performed countless research activities and have developed computer software to facilitate and support end-user implementation of arc flash hazard protection measures.

The electrician must understand the basic concepts of arc hazard potential and the requirements for working safely in such identified areas. However, the electrician performing a task does not need to know the physics behind the calculations for either thermal energy released in an arc blast or the associated safe work zone dimensional boundaries established.

Formula for Calculating Electrical Arc Flash Hazard Boundaries

For calculating the Electrical Arc Flash Hazard Boundary, the formula below can be used. Or use a software package as referenced in this section to calculate the Electrical Arc Flash Hazard Boundary. Or use Table 1 in this section to establish the Electrical Arc Flash Hazard Boundary.

The Formula

Dc = [2.65 x MVABF x t}1/2  This formula is used when Short Circuit Current (Isc) is known.

Variables:

·            Dc represents the distance (in feet) of a person from an arc source for curable second-degree burns

·            t equals the time (in seconds) of arc exposure.

·            MVABF is the bolted fault MVA (megavolt-amperes) at the point involved.

·            MVA equals the MVA rating of transformer (for transformers with MVA ratings below 0.75 MVA, multiply the transformer rating by 1.25). The MVA value is used only in simple, one-transformer calculations.

Performing an Electrical Arc Flash Hazard Boundary Calculation

Given the following information, calculate the Arc Flash Hazard Boundary.

·            50 MVA transformer (base MVA of 50)

·            Impedance (Z) of 6.75% on a 13,800 volt bus.

·            Fault clearance time (t) of 6 cycles (0.1 seconds for 60Hz).

Table 1.

Step 1- Calculate the bolted fault MVABF

MVABF = MVABASE/Z

50/.0675 = 741

Step 2- Calculate the flash hazard boundary (Dc)

Dc = [2.65 x MVABF x t]1/2

[2.65 x 741F x 0.1]1/2 = 14

Calculate the Short Circuit Current

Isc =  (MVABF / (√3 x bus voltage)) x 1,000,000

(741/(√3 x 13,800)) x 1,000,000 =  31,000

 

Variables:

·            Dc represents the distance (in feet) of a person from an arc source for curable second-degree burns

·            t equals the time (in seconds) of arc exposure.

·            MVABF is the bolted fault MVA (megavolt-amperes) at the point involved.

·            Z = Transformer Impedance

·            Isc = Short Circuit Current

·            ½ is the square root

Electrical Arc Flash Hazard Boundary for All Applications

When an Arc Flash Hazard is present, personnel must know the Electrical Arc Flash Hazard Boundary. If a person is within the Electrical Arc Flash Hazard Boundary, choose the PPE to protect to less than or equal to 1.2 calories/cm2. Elimination of the Arc Flash Hazard ends the need for an Electrical Arc Flash Hazard Boundary. Required PPE for common tasks is discussed in the Personal Protective Equipment section of this learning guide.

If a arc flash hazard boundary calculation has not been performed, Table 2 must be used to determine the boundary. Be sure the voltage levels and MVABF are less than or equal to those listed below.

Table 2

Electrical System Voltage Phase to Phase

Electric Arc Flash Hazard Boundary Dc

kV

Feet

Meters

.051 - .600

4.0

1.2

.601 - .999

6.0

2.0

1.0 - 15

14.0

4.3

15.1 - 36

16.0

5.0

36.1 - 46

20.0

6.0

For values above 46kV, calculate the Electric Arc Flash Hazard

Boundary.

 

 The calculations in the above table are based on the following bolted faults:

·            51 – 600 volts: 50 bolted fault MVA and a fault clearing time of 6 cycles (0.1 seconds)

·            601 – 999 volts: 100 bolted fault MVA and a fault clearing of 6 cycles (0.1 seconds)

·            1 kV – 15 kV: 750bolted fault MVA and a fault clearing of 6 cycles (0.1 seconds)

·            15.1 kV – 36 kV: 1000 bolted fault MVA and a fault clearing of 6 cycles (0.1 seconds)

·            36.1 kV – 46 kV: 1500 bolted fault MVA and a fault clearing of 6 cycles (0.1 seconds)

Calculating Arc Thermal Energies

Calculated Arc Thermal Energies are used to determine the appropriate PPE required that will protect the worker from greater than second degree bums, and must reduce Arc Flash Hazard exposure to less than 1.2 cal/cm2.  

When calculating Arc Thermal Energies, choose the distance from the arc source to the worker's torso. Choose distances of 18" or greater. Table 3, below, allows determination of potential Arc Thermal Energies, without calculation, if the Arc Fault Current is known.

Arc Flash incidents may occur in open air or in confined boxes (controllers). The resultant thermal energy associated with an arc flash is different based on the situation and therefore must be calculated differently.

Below are the formulas used.

Formula for Calculating Arc Thermal Energy for 600 volts or less in Open Air

EMA = 5271 x DA-1.9593 x tA x [0.0016F2 - 0.0076F + 0.8938]

where:

·         EMA = maximum open Arc Thermal Energy in calories/cm2

·         DA= distance in inches from the arc source to the worker's torso. Valid for distance of 18" and greater.

·         TA = arc duration in seconds

·         F = bolted fault short circuit current in kA (valid for 16 to 50 kA).

Formula for Calculating Arc Thermal Energy for 600 volts or less in a Box

EMB = 1038.7 x DB-1.4738 x tA x [0-0093F2 - 0.3453F + 5.9675]

where:

·         EMB = maximum 20-inch cubic box Arc Thermal Energy in calories/cm2

·         DB = distance in inches from the arc source to the worker's torso. Valid for distance of 18" and greater.

·         TA = arc duration in seconds

·         F = bolted fault short circuit current in kA (valid for 16 to 50 kA).

Potential Arc Thermal Energies in Open Air for known Short Circuit Currents

For voltages in Open Air, use the table below or calculate Arc Thermal Energies using the appropriate software (discussed later).


Table 3

Supply Voltage in kV

Short Circuit Currents in kA

Arc Gap

Distance from Arc to worker's location

Arc Duration

10

20

30

40

60

80

100

Total Calories/cm2 to workers

Inches

cm

Inches

cm

Seconds

0.300

.60

1.72

3.36

5.56

11.7

20.2

31.1

1.25

3

18

46

0.1

0.480

.60

1.72

3.36

5.56

11.7

20.2

31.1

1.25

3

18

46

0.1

0.600

.60

1.72

3.36

5.56

11.7

20.2

31.1

1.25

3

18

46

0.1

0.750

0.87

2.37

4.47

7.21

14.6

24.7

37.5

2

5

18

46

0.1

1.0

0.70

1.77

3.17

4.93

9.48

15.4

22.8

4

10

26

66

0.1

2.4

0.92

2.24

3.92

5.96

11.1

17.7

25.8

6

15

26

66

0.1

4.16

1.08

2.58

4.45

6.69

12.3

19.3

27.8

8

20

26

66

0.1

13.2

1.56

3.55

5.76

8.25

13.9

20.4

27.3

12

30

26

66

0.1

13.8

1.56

3.55

5.76

8.25

13.9

20.4

27.3

12

30

26

66

0.1

15

1.56

3.55

5.76

8.25

13.9

20.4

27.3

12

30

26

66

0.1

22

1.62

3.70

5.99

8.57

14.5

21.2

28.4

18

46

31

79

0.1

34.5

1.78

4.07

6.60

9.44

15.9

23.3

31.3

20

50

31

79

0.1

46

1.50

3.41

5.53

7.91

13.3

19.6

26.2

20

50

34

86

0.1

Above Arc Thermal Energy calculations based on using ARCPRO software version 2.0. ARCPRO is a product of Ontario Hydro Technologies, Toronto, Ontario, Canada.

 

Notes:

Arc energies computed by ARCPRO have been verified by comparison with measured results from high current laboratory tests involving controlled vertical arcs in air. ARCPRO results have shown good agreement with measured values from a series of tests covering the following ranges of parameters: currents from 3.5 kA 0 21.5 kA, arc durations from 4 cycles to 30 cycles, arc lengths from 1 inches to 12 inches, and distances of 8 inches to 24 inches from the arc.

ARCPRO assumes ac symmetrical currents with 60-Hz frequency free-burning vertical arcs in air. ARCPRO does not account for the following additional criteria: movement of the arc, electrode materials such as aluminum, hot particles being ejected from the arc, 3-phase arcs or arcs in enclosures. ARCPRO is most applicable to arcs longer Tan Z5 cm and arc currents above 200 A rms.

Duke Heat Flux Calculator Freeware provides reasonable estimates within the range of 1kA and 10 kA. Heat Flux limitations include: program termination for values outside of modeled ranges for arc gap and voltage, and poor estimates for small arc gaps at higher currents and voltages.

ox for known Short Circuit Currents

For voltages in a Cubic Box, use the table below or calculate Arc Thermal E using the "Formula for Calculating Arc Thermal Energy in a Box discussed earlier.

Supply Voltage in kV

Short Circuit Currents in kA

Arc Gap

Distance from Arc to worker's location

Arc Duration

20

30

40

60

Total Calories/cm2 to workers

Inches

cm

Inches

cm

Seconds

0.300

1.72

3.36

5.56

11.7

1.25

3

18

46

0.1

Arc Thermal Performance Value (ATPV)

Each piece of clothing worn by an employee will provide some level of protection from an arc flash. As layers of clothing, and air gaps, are applied they have a cumulative effect in protection. The level of PPE is the sum of the ATPV ratings for each layer.

Determine PPE Required for a Task

If an Arc Flash Hazard Analysis is not performed, personnel must wear the PPE Level listed in Table 4.

Personnel must wear the appropriate PPE for the determined Arc Flash Hazard level. In order to protect personnel from injuries greater than second degree bums, the PPE must reduce Arc Flash Hazard exposure to less than 1.2 cal/cm2.

Personnel shall not wear articles containing conductive material such as rings, metal watch bands, metal-framed eyewear, and dangling metal jewelry when within the Electrical Arc Flash Hazard Boundary. Wearing of post type earrings shall be determined by location policy.

The clothing and PPE required for a task is dependent upon the potential hazard exposure and are categorized into five levels that provide adequate protection. Descriptions of these levels are found on the following pages.

For PPE Levels 1 to 4, clothing and equipment providing the same level of protection (calories/cm2) may be used instead of the specific brands or fabric weights (oz/yd 2). PPE selected should not increase other hazards. Natural fiber clothes and undergarments must be 100 percent cotton, 100 percent wool, or have equivalent ignition properties that will not increase the extent of bum injury. Undergarments may have elastic supports.

  

 

Arc Flash Incident

 

PPE

 

Exposure to Personnel

Level 1

1.2 calories

Level 2

1.2 calories

Level 3

1.2 calories

Level 4

1.2 calories

Arc hazard levels in Table 4 are based upon fault clearing times of less than or equal to six cycles (0.1 seconds), and fault currents not to exceed 40kA. If longer fault clearing times and/or fault currents greater than 40KA are exceeded, an Arc Flash Hazard Analysis SHALL be performed.

 

Table 4.5 – PPE Levels for Common Voltage Tasks Performed within an Electrical Arc Flash Hazard Boundary

Common Voltage Task

Panels, switches or enclosed switchgear 51 V – 240 V, 10 kA or greater short circuit current.

Switching or breaker operation with covers on with no exposed, energized parts, excluding wall mounted, covered toggle or similar switches typically used for lighting, etc.

0

Switching or breaker operation, testing, troubleshooting, doors opened. For less than 10 kA short circuit current available, the PPE Level required may be reduced by 1.

1

Panels, switches or enclosed switchgear 241 V – 999 V.

Switching or breaker operation doors closed, no exposed, energized parts less than 600 amps. See Note 1.

0

Switching or breaker operation with doors closed, 600 amps or greater. See note 2.

1

Racking in or out Circuit Breakers, Cubicle doors open.

3

Removing bolted covers to exposed energized parts.

3

Switching or breaker operation, testing, troubleshooting with doors open. See Note 3.

2

Enclosed switchgear 1kV and above.

Switching or breaker operation with doors closed. See Note 2.

2

Switching or breaker operation with doors open.

4

Voltage testing and applying safety grounds.

4

Work on control circuits near exposed, energized high voltage parts.

4

Opening panel doors or compartment covers to exposed, energized high voltage parts

4

Outdoor Equipment, open air, 1kV and above.

Disconnect switch operation, gang operated from grade.

 

Disconnect switch operation, live line tool (hot stick) operated.

 

Work on energized parts, inducing voltage testing.

 

Application of Safety Grounds after voltage testing.

 

Note - Aluminum enclosures provide limited Arc Flash Hazard protection. If the fault level is above 25,000 Amps or the main over current device is 1200 Amps or greater, at a minimum, Level 1 clothing with hand and face protection is required.

Note 1- If there is increased danger of injury due to Arc Flash Hazard because of any openings in the door, panel or covers, including ventilation opening, hand protection and/or face protection may be required. Hand protection shall consist of a minimum weight of 2.75 ounce leather glove with gauntlet of sufficient length to provide wrist protection. Face Protection shall consist of a tinted, propionate, wrap around face shield over safety glasses or goggles.

Note 2 - PPE Level 0, if rated and tested Arc Fault Contained Switchgear.

Note 3 - Requires the use of Face Shield and Hearing Protection.

Level 0 PPELevel 0 PPE consists of untreated cotton clothing including a minimum of long sleeves and, long pants and safety glasses with side shields. This level provides no appreciable protection from Arc Flash Hazard energy.

Level 1 PPELevel 1 PPE must provide protection to 5 calories/cm2 from potential Arc Flash Thermal Energy. Level 1 PPE total clothing weight usually is 4.5 oz/yd 2 to 8 oz/yd 2 and may consist of:

·               FR long sleeve shirt and FR long pants, FR Coveralls or 50" FR smock;

·               Safety glasses with side shields and electrically non-conductive frames;

·               Polycarbonate or propionate goggles, if goggles are required;

·               Electrically-rated safety shoes;

·               Electrically non-conductive hardhat; and

·               Arc Flash Hazard rated gloves shall be worn to protect against the Arc Flash Hazard energy for this level of PPE. Voltage rated gloves are required if electrical contact hazard exists or their use is mandated by other codes or standards. Voltage rated gloves with leather protection may meet the requirements for both Arc Flash Hazard and electrical contact hazard.


Level 2 PPE

Level 2 PPE must provide protection to 8 calories/cm2 from potential Arc Thermal Energy, Level 2 PPE total clothing weight of all layers usually is 9 oz/yd2 to 12 oz/yd2 and may consist of:

First Layer

·         100 % cotton underwear, including short sleeve shirt.

Second Layer

·         FR long sleeve shirt and FR long pants, FR Coveralls or 50" smock.

Other PPE:

·         Safety glasses with side shield and electronically non-conductive.

·         Electrically non-conductive hardhat.

·         Hearing protection

·         Arc Flash rated gloves shall be worn to protect against the Arc Flash Hazard energy for this level PPE. Voltage rated gloves are required if the electrical contact hazard exists or their use is mandated by other codes or standards.

·         Voltage rated gloves with leather protection may meet the requirements for both Arc Flash Hazard and electrical contact hazard.

 

 

 

Level 3 PPE

Level 3 PPE must provide protection to 25 calories/cm2 from potential arc fault energy. Level 3 PPE total clothing weight of all layers usually is 16 oz/yd2 to 20 oz/yd2 and may consist of:

First Layer

·         100 % cotton underwear, including short sleeve shirt.

Second Layer

·         FR long sleeve shirt and FR long pants, FR Coveralls or 50" smock.

Third Layer:

·         Single layer Nomex 50" length smock or coveralls

·         Nomex hood or hood cape

·         Wrap around arc rated face shield

Other PPE:

·         Safety glasses with side shields and electrically non-conductive

·         Polycarbonate or propionate goggles, if goggles are required

·         Electrically rated safety shoes

·         Electrically non-conductive hardhat

·         Hearing Protection

·         Arc Flash rated gloves shall be worn to protect against the Arc Flash Hazard energy for this level PPE. Voltage rated gloves are required if the electrical contact hazard exists or their use is mandated by other codes or standards.

·         Voltage rated gloves with leather protection may meet the requirements for both Arc Flash Hazard and electrical contact hazard.

 Level 4 PPE

Level 4 PPE must provide protection to 40 calories/cm2 from potential arc fault energy. Level 3 PPE total clothing weight of all layers usually is 24 oz/yd2 to 30 oz/yd2 and may consist of:

First Layer

·         100 % cotton underwear, including short sleeve shirt.

Second Layer

·         FR long sleeve shirt and FR long pants, FR Coveralls or 50" smock.

Third Layer:

·         Multi-ply Nomex III 50" length switcher's coat

·         Nomex switcher's hood with wrap around arc rated face shield

Other PPE:

·         Safety glasses with side shields and electrically non-conductive

·         Polycarbonate or propionate goggles, if goggles are required

·         Electrically rated safety shoes

·         Electrically non-conductive hardhat

·         Hearing Protection

·         Arc Flash rated gloves shall be worn to protect against the Arc Flash Hazard energy for this level PPE. Voltage rated gloves are required if the electrical contact hazard exists or their use is mandated by other codes or standards.

·         Voltage rated gloves with leather protection may meet the requirements for both Arc Flash Hazard and electrical contact hazard.

Carand Maintenance of PPE

PPE shall be inspected, maintained, and cared for according to the manufacturer's specifications. PPE shall be inspected before each use per the manufacturer's recommendations. Any damaged PPE shall be removed from service. PPE soiled with grease or flammable liquids shall be removed from service and property cleaned. PPE damaged in an arc flash incident shall be removed from service.

Creating a Safe Work ZonePersonnel without appropriate PPE shall not cross an Electrical Arc Flash Hazard Boundary and enter a work area where an Arc Flash Hazard is present. To establish  Safe Work Zone where voltages are less than 1000 volts AC, establish appropriate safe work practices to protect personnel from hazards present in the work zone. To establish a Safe Work Zone where voltages are greater than 1000 Volts AC, follow the requirements in High Voltage.1, Section 8.0.


Avoiding Electrical Shock”

Electrical hazards can be found in all industries.

Avoiding electrical shocks both at home and at work requires awareness of the hazards and a respect for this "Silent Killer."

The human body has a low resistance to electricity, making it a good conductor, like most metals.

Unlike metals however, the human body does not respond well when electricity passes through it.

Physical results include thermal burns, disruption of normal heart activity, severe muscle contractions, and even death.

The most common and serious electrical injuries occur when electrical current flows between the hands and feet.

This happens when a person touches an energized line.

The electrical energy is looking for the shortest path to the ground, and it will pass through the body to the feet to reach it.

When this occurs, a person’s heart and lungs are frequently damaged by the electrical energy.

Placing an insulator between the energy and the point of physical contact is one method of protection.

Porcelain, rubber, pottery and dry wood offer substantial resistance to the flow of electricity, and are therefore good insulators.

These materials can often protect a person from electrical shock.

Precautions for avoiding electrical shocks include, but are not limited to, the following:

Always make sure electric tools are properly grounded or double insulated.

The double insulated tool must have an undamaged outer case and be clearly labelled as "double insulated" by the manufacturer.

Always check to be sure the grounding system is complete.

Unless they are designated as double insulated, grounded power tools must be attached to a grounded service circuit.

If there is any doubt about the grounding, test it! (Ground testers are inexpensive.)

Use heavy duty grounded extension cords. These cords have two layers of insulation, with reinforcement between the layers.

They are less susceptible to damage than house-hold type cords.

To check if the cord is heavy duty, check its shape. Most flat cords are not heavy duty.

Heavy duty cords will have a marking on the insulation such as: "S", "SJ", "SJO", etc.

Avoid mixing water and electricity! Not only keep cords, tools and working/walking surfaces dry, keep your hands and feet dry as well.

The electrical resistance of wet skin is at least 100 times less than dry skin.

Wet skin greatly increases the likelihood of severe shock if a person comes in contact with a live circuit.

If you must work around water, connect to a Ground Fault Circuit Interrupter (GFCI) to automatically shut off the current if there is an abnormal current flow.

Never work on or around a live electrical circuit. Lock Out the power so that only you have control over energizing the machine or equipment.

Periodic Reviews

Annual self-assessments of the location's electrical safety program shall be conducted to ensure personnel are complying with the requirements of this document, and that personnel are wearing the proper PPE to eliminate Arc Flash Hazard injuries. Action plans shall be developed to close any identified gaps.

Modifications, Changes or Additions to Electrical Systems

If modifications, changes or additions to the electrical system occur, a reassessment shall be completed to verify the Arc Flash Hazard and PPE requirements. The reassessment documentation shall include modifications completed, modified Arc Flash Hazard or PPE required, date and assessor's name.

Design of Electrical Systems to Limit Arc Flash Hazards

An Arc Flash Hazard Assessment shall be conducted on any newly designed electrical systems. Priority must be given to eliminating the Arc Flash Hazard through the appropriate engineering and design.

After January 1, 2004, new switchgear rated for 1000 volts and above must be arc fault rated with integral grounding switches and viewing windows. See document 32.25.4 titled "4.16 Thru 34.5 kV Switchgear Centers Enclosed" for additional switchgear specifications.

Back To Safety Programs            Home