SC Tri Association Facility Managers Conference Arc Flash & - - PowerPoint PPT Presentation

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SC Tri Association Facility Managers Conference Arc Flash & - - PowerPoint PPT Presentation

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SC Tri Association Facility Managers Conference Arc Flash & Electrical Safety RMF Engineering Dennis Sepavich, PE Arc Flash & Electrical Safety Agenda Introductions What is an Arc Flash? Industry codes and standards

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Arc Flash & Electrical Safety

Arc Flash & Electrical Safety

RMF Engineering Dennis Sepavich, PE

SC Tri Association Facility Managers Conference

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SLIDE 2

Arc Flash & Electrical Safety

Agenda

 Introductions  What is an Arc Flash?  Industry codes and standards  Personal Protective Equipment (PPE)  What is involved an Arc Flash Study?

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Arc Flash & Electrical Safety

Presenter

 Dennis Sepavich, PE  Joined RMF Engineering in 2006  Project Manager / Electrical

Engineer at RMF

 Licensed Professional Engineer, 2002

(SC,NC,GA,FL,AL,AK,VA,NY,MA,IL)

 Licensed Journeyman Electrician,

1992

 31 years experience in the Electrical

Construction Industry

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Arc Flash & Electrical Safety

WHAT IS AN ARC FLASH?

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Arc Flash & Electrical Safety

What is an Arc Flash

 A rapid release of energy

due to an arcing fault between two electrical conductors (bus bars)

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Arc Flash & Electrical Safety

What is an Arc Flash

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SLIDE 7

Arc Flash & Electrical Safety

Arc Flash Accident

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Arc Flash & Electrical Safety

CODES AND STANDARDS

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Arc Flash & Electrical Safety

Industry Standards

 OSHA 1910.132(d) Hazard

Assessment and equipment selection

 OSHA 1910.312(f)

Training

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Arc Flash & Electrical Safety

Industry Standards

 National Electrical Code  110.16 Arc Flash Warning

Label

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Arc Flash & Electrical Safety

Industry Standards

 National Electrical Code  110.24 Field Marking

Available Fault Current

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Arc Flash & Electrical Safety

Industry Standards

 NFPA 70E  Article 130 – Electrically

Safe Working Conditions

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Arc Flash & Electrical Safety

Industry Standards

 NFPA 70E  Article 130 –

Lockout/Tagout

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Arc Flash & Electrical Safety

Industry Standards

 NFPA 70E  Energized Work Permit

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Arc Flash & Electrical Safety

Industry Standards

 NFPA 70E  130.5 Arc Flash Risk

Assessment

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Arc Flash & Electrical Safety

Industry Standards

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Arc Flash & Electrical Safety

Industry Standards

 IEEE 1584  Guide for Performing Arc

Flash Hazard Calculations

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Arc Flash & Electrical Safety

Industry Standards

 IEEE 1584  Includes Incident Energy

Calculation equations used by software programs

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Arc Flash & Electrical Safety

PERSONAL PROTECTIVE EQUIPMENT

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Arc Flash & Electrical Safety

Personal Protective Equipment

 Shock Hazard Protection

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Arc Flash & Electrical Safety

Personal Protective Equipment

 Arc Flash Protection

8 calorie suit 12 calorie suit 40 calorie suit

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Arc Flash & Electrical Safety

Personal Protective Equipment

 Arc Flash Protection

100 calorie suit

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Arc Flash & Electrical Safety

WHAT IS INVOLVED IN AN ARC FLASH STUDY?

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Data Collection  Document existing conditions

(Voltage, Ampacity, circuit breaker settings, feeder sizes and conductors lengths)

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Develop One-Line

Diagram

 Input field data into one-

line diagram format in software program

U2A_PRI

Manufacturer SQUARE D 225 A Sensor/Trip 200 A LH Settings Thermal Curve INST LO (1000A)

S P

U2A XF

Size 75 kVA Pri Delta 480 V Sec Wye-Ground 208 V %Z 3.20 % X/R 0.9

PNLU2A SE C-U2AXF-FDR

(1) Size 3/0 AWG/kcmil Copper 3-1/C+G THWN 100 ft Ampacity 200 A

U2A XF PRI C-U2A-FDR

(1) Size 4/0 AWG/kcmil Copper 4-1/C+G THHN 100 ft Ampacity 260 A

U2A XF SEC U2A_PNL1

Manufacturer SQUARE D 100 A Sensor/Trip 100 A QO, 3-Pole Settings Fixed (730-7, 100A)

U2A_SEC

Manufacturer SQUARE D 250 A Sensor/Trip 250 A QD Settings Fixed

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SLIDE 26

Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Short Circuit Study  Determine the fault

current at each bus in the electrical distribution system

U2A_PRI

S P

U2A XF PNLU2A SE

208 V Asym3P 1/2 Cycle 2808 A Asym3P 5 Cycle 2768 A

C-U2AXF-FDR U2A XF PRI

480 V Asym3P 1/2 Cycle 3229 A Asym3P 5 Cycle 2562 A

C-U2A-FDR U2A XF SEC

208 V Asym3P 1/2 Cycle 3371 A Asym3P 5 Cycle 3274 A

U2A_PNL1 U2A_SEC

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Short Circuit Study  Identifies any circuit

breakers that may not be rated for the available fault current (over duty)

 Presents a serious safety

hazard

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SLIDE 28

Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Protective Device

Coordination

 Compare time current

curves to ensure the

  • vercurrent device closest

to the load trips first (Selective Coordination)

0.5 1 10 100 1K 10K 0.01 0.10 1 10 100 1000 CURRENT IN AMPERES Selective Coordination.tcc Ref. Voltage: 480V Current in Amps x 10 TIME IN SECONDS

SQUARE D PA PA Trip 1200.0 A Settings Phase Thermal Curve INST LO (3480A)

800A MCB

SQUARE D LH LH Trip 250.0 A Settings Phase Thermal Curve INST LO (1250A)

400A BKR

SQUARE D PA PA Trip 1200.0 A Settings Phase Thermal Curve INST LO (3480A)

800A MCB

SQUARE D LH LH Trip 250.0 A Settings Phase Thermal Curve INST LO (1250A)

400A BKR

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Protective Device

Coordination

 Circuit Breakers with

adjustable electronic trip units may be able to be adjusted to lower the incident energy which reduces the arc flash hazard

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Arc Flash & Electrical Safety

What is Involved in an Arc Flash Study

 Arc Hazard Analysis  Calculate the incident

energy at each bus

 Dependent on level of

arcing fault current

 Clearing time of upstream

device

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Arc Flash & Electrical Safety

Example

 1200 Amp MCCB with

adjustable instantaneous trip

0.5 1 10 100 1K 10K 0.01 0.10 1 10 100 1000 CURRENT IN AMPERES 1200A TM MCCB.tcc Ref. Voltage: 480V Current in Amps x 10 TIME IN SECONDS

SQUARE D PA PA Trip 1200.0 A Settings Phase Thermal Curve INST LO (3480A)

1200A TM MCCB

SQUARE D PA PA Trip 1200.0 A Settings Phase Thermal Curve INST LO (3480A)

1200A TM MCCB

Arc Flash Boundary = 21” Incident Energy = 1.6 cal/cm2

Clearing Time (Arc Duration)

= 0.053 Seconds

Arcing Current 7,080 Amps

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Arc Flash & Electrical Safety

Example

 1200 Amp LVPCB with

electronic trip unit

0.5 1 10 100 1K 10K 0.01 0.10 1 10 100 1000 CURRENT IN AMPERES 1200A ET.tcc Ref. Voltage: 480V Current in Amps x 10 TIME IN SECONDS

SQUARE D Masterpact NT, 5.0 & 6.0 A/P/H NT12H Trip 1200.0 A Settings Phase LTPU (A);LTD 1 (1200A); 1 STPU 10 (12000A) STD 0.3 (I^2t In) INST (NTxxN, NTxxH) 10 (12000A)

1200A ET MCCB

SQUARE D Masterpact NT, 5.0 & 6.0 A/P/H NT12H Trip 1200.0 A Settings Phase LTPU (A);LTD 1 (1200A); 1 STPU 10 (12000A) STD 0.3 (I^2t In) INST (NTxxN, NTxxH) 10 (12000A)

1200A ET MCCB

Arc Flash Boundary = 151” Incident Energy = 39 cal/cm2

Clearing Time (Arc Duration)

=1.568 Seconds

Arcing Current 6,020 Amps

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Arc Flash & Electrical Safety

Example

 1200 Amp Power Circuit

Breaker w/o instantaneous protection

0.5 1 10 100 1K 10K 0.01 0.10 1 10 100 1000 CURRENT IN AMPERES 1200A LVPCB.tcc Ref. Voltage: 480V Current in Amps x 10 TIME IN SECONDS

GE THS Power Break THS Trip 1200.0 A Settings Phase LTPU (0.7-1.0 x S) 0.7 (840A); Fixed STPU (LO-HI) LO (3600A); Fixed

1200A LVPCB

GE THS Power Break THS Trip 1200.0 A Settings Phase LTPU (0.7-1.0 x S) 0.7 (840A); Fixed STPU (LO-HI) LO (3600A); Fixed

1200A LVPCB

Arc Flash Boundary = 62” Incident Energy = 9 cal/cm2

Clearing Time (Arc Duration)

= 0.304 Seconds

Arcing Current 7,080 Amps

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Arc Hazard Analysis  Determine the Arc Flash

Boundary

 Distance where

unprotected person can receive a 2nd degree burn >1.2 cal/cm²

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Arc Flash Label

2015 NFPA 70E: PPE Categories removed from the label

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Arc Flash Labels  Place labels on the

equipment

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Arc Flash & Electrical Safety

What is involved in an Arc Flash Study

 Keep it current  Review and update the

study when any changes are made to the system

 Minimum every 5 years

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Arc Flash & Electrical Safety

Why perform Arc Flash Studies

 Prevent worker injury or

death

 Avoid or reduce litigation

associated with an electrical injury

 Comply with codes and

standards to avoid citations and fines

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Arc Flash & Electrical Safety

Summary

 Basic understanding of

arc flash

 Overview of codes and

standards associated with arc flash and electrical safety

 Overview of what goes

into an arc flash study

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Arc Flash & Electrical Safety

Dennis Sepavich, PE dennis.sepavich@rmf.com

THANK YOU!!!