RME Arc Flash Hazards Awareness

ARC FLASH HAZARD AWARENESS ESSENTIALS FOR

MASTER ELECTRICIANS

IMPORTANT ACKNOWLEDGEMENT: Figures and texts used in this presentation were taken from [R1] Arc Flash Hazard Analysis and Mitigation (J.C. DAS), [R2] IEEE GUIDE 1584, [R3] NFPA

70E [R4] PEC 1-2009, [R5] PEC 2-2008, [R6] NESC 2002 & 2012, [R7] The Electrical Safety Program Guide (Jones), [R8] OSHS and [R9] NEC (2005, 2008, 2011, & 2014) with some edits

and/or revisions by ENGR. SERA JOSEF.

NOTICE: This presentation does not reflect the official position of the IIEE. The recommendations by ENGR. SERA JOSEF in this presentation are intended to be in

compliance with the PEC and other related standards.

Raul S. Sera Josef Bulacan State University

[email protected] / [email protected] / [email protected]

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ARC FLASH HAZARD AWARENESS ESSENTIALS FOR MASTER ELECTRICIANS RAUL S. SERA JOSEF, REE18923/RMsE20185

• IIEE Lifetime Member No. 13444 • IIEE Bulacan Chapter President (2001) • REE18923 / RMsE20185 • TESDA NC III (Electrical Installation and Maintenance) • TESDA NC II (Electrical Installation and Maintenance, Mechatronics Servicing,

& Technical Drafting) • Sole Lecturer, IIEE-Central Laguna Chapter’s Electrical Proficiency Program for

Electricians (100 to 120 hours per Batch) (Batch Nos. 1 to 3) • Technical Assistant, IIEE National Office (1999-2001) • Lecturer, IIEE Seminar “PEC 1-2009 Essentials for Master Electricians” • Electrical Instructor, Bulacan State University (2002-Present) • Electrical Trainer (On-Call), Gokongwei Brothers Foundation (2013-Present) • Proponent: BIT-Mechatronics Technology at Bulacan State University • BSEE, 2-&3-Year Technician Educucation, BulSU • MAEd (Physics) at BulSU (Thesis Writing) • MSEE (Power System) Student (as CHED Scholar) at UP-Diliman (Thesis

Proposal)

ABOUT THE LECTURER: RAUL S. SERA JOSEF

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Agenda:

What is an Arc Flash? How does an Arc Flash happen?

Factors that affect Arc Flash Effects of an Arc Flash

Intro to Arc Flash Protection Selection of Personal Protective Equipment (PPE)

Labeling of Electrical Equipment Electrical Approach Boundaries Arc Flash Protection Boundary

Limited Approach Boundary Restricted and Prohibited Approach Boundary

Hazard Assessment and Risk Evaluation Process for Arc Flash

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Arc Flash Incident

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Arc Flash Incident [6-Cycle = 0.1 Sec.]

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Arc Flash Incident

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Arc Flash Incident <0.5-Cycle = <0.0083 Sec.

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1PEC20091.10.1.16

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2008NEC110.16

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2008NEC110.16

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2011NEC110.16

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2011NEC [110.16] 2014NEC

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2011NEC110.24

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2014NEC110.21

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Electrical Safety

Electrical Safety. Recognizing (electrical) hazards associated with the use of electrical energy and taking precautions so that (electrical) hazards do not cause injury or death. [NFPA 70E-2012] See OSHS Rule 1210 – Electrical Safety. OSHS Rule 1211: Philippine Electrical Code (PEC). The PEC is hereby adopted and the standards contained therein shall be considered. Safety standards to the extent that they safeguard any person employed in any workplace and control the practice of electrical engineering.

Electrical hazards are especially difficult for workers to guard against without specialized training and procedures they can follow. [Jones]

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Electrical Hazards

Electrical Hazards. Dangerous conditions such that contact or equipment failure can result in electric shock, arc flash burn, thermal burn, or blast. [NFPA 70E-2012] Three (3) General Categories of Electrical Hazards [NFPA 70E-2012]: Electric Shock, Arc Flash, & Arc Blast

Electrical hazards are especially difficult for workers to guard against without specialized training and procedures they can follow. [Jones]

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General Categories of Electrical Hazards

Electrical Shock Arc Flash Arc Blast

Shock Hazard. A dangerous condition associated with the possible release of energy caused by contact or approach to energized electrical conductors or circuit parts. [NFPA 70E]

Arc Flash Hazard. A dangerous condition associated with the possible release of energy caused by an electric arc. [NFPA 70E]

Associated with thermal hazard and burns.

Arc Blast is associated with extreme pressure and rapid pressure build up.

Solid to a vapor (67,000 x Cu expand)

US-NSC: 30,000 nonfatal/year, 1,000 fatal/year (half at <600V)

2000 severe burns/year

If the equipment is maintained under deenergized condition, there is no arc flash hazard. [DAS]

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Statistics

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What is an Arc Flash?

An electric arc is a short circuit through the air.

Source: Electrical Safety, Arc Flash/Blast Injuries Prevention for Workers, Geogia Tech Research Institute

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ARC FLASH is dangerous condition associated with the unexpected release of tremendous amount of energy caused by an ELECTRIC ARC within electrical equipment.

This release is in the form of intense light, heat, sound, and blast of arc products that may consist of vaporized components of enclosure material –

copper, steel, or aluminum.

Intense sound and pressure waves also emanate from the ARC FLASH, which resembles a condined explosion.

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How does an Arc Flash happen?

ARCING occurs when the insulation between the live conductors breaks down, due to aging, surface tracking, treeing phenomena, and due to human error when maintaining electrical equipment in the energized state. [DAS]

The INSULATION SYSTEMS are not perfectly homogenous and voids form due to thermal cycling. In nonself restoring insulations, TREEING PHENOMENA starts with a discharge in a cavity, which enlarges over a period of time, and the discharge pattern resemble tree branches, hence the TREEING. [DAS]

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How does an Arc Flash happen?

ELECTRICAL ARCING signifies the passage of current through what has previously been air. It is initiated by flashover or introduction of some conductive material. The current passage is through ionized air and the vapor of the arc terminal material, which has substantially higher resistance that the solid material. [DAS]

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Limits of Approach

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Hazard Boundaries

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Hazard Boundaries

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Hazard Boundaries

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1.10.1: WORKING DISTANCE

Working Distance: The dimension between the possible arc point and the head and body of the worker positioned in place to perform the assigned task. [IEEE 1584-2002]

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1PEC1.10: Working Space [Table 1.10.2.1(a)(1)]

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2PEC2008: Definition [1.2]

Spacing Vs. Clearance

Balikbayan REE

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1.10.2.1(a,e)

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1PEC1.10: 1.10.2.1(a)

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1PEC1.10: 1.10.2.1(e)(1)

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1PEC1.10: Working Space [1.10.2.1(a)(1)a]

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1PEC1.10: Working Space [1.10.2.1(a)(1)b]

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1PEC1.10: Working Space [1.10.2.1(a)(2)]

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1PEC 1.10.2.1(c) & 2PEC 2.2.4

Panic Bars

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1PEC1.10: Working Space [1.10.2.1(b)]

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1.10.2.1(b) / 4.50.3.8

Clear Spaces. Working space required by 1.10.2.1(b) shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.

Storage in Vaults. Materials shall not stored in transformer vaults. (4.50.3.8)

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1PEC1.10: Working Space [1.10.2.1(c)]

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1.10.2.1(c)(1)

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1PEC 1.10.2.1(c) & 2PEC 2.2.4

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1PEC 1.10.2.1(c) & 2PEC 2.2.4

Personnel Doors. Where equipment rated 1200 A or more that contains overcurrent devices, switching devices, or control devices is installed and there is a personnel door(s) intended for entrance to and egress from the working space less than 7.6 m (25 ft) from the nearest edge of the working space, the door(s) shall open in the direction of egress and be equipped with panic bars, pressure plates, or other devices that are normally latched but open under simple pressure.

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1PEC1.10: Working Space [1.10.2.1(d)]

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1PEC1.10: Dedicated Elect’l Space [1.10.2.1(f)(1)a]

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PEC1.10: Dedicated Equip. Space [1.10.2.1(f)(1)a]1

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1PEC1.10: Dedicated Equip. Space [1.10.2.1(f)(1)b]

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Personal Protective Equipment (PPE)

A workplace that puts employees in an environment that contains electrical hazards must have a strategy to protect its workers. [Jones]

PROTECTIVE STRATEGIES

1st: To Isolate workers from electrical hazards by creating an electrically safe working condition.

2nd: To identify approach boundaries.

3rd: To use PPE to prevent injury in the event of an incident.

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•OSHS Rule 1080- PPE - safety shoes: to protect our FEET from any hazard

•OSHS Rule : 1085.01: When selecting gloves, consideration should be given to the hazards to which the wearer may be exposed to and the ease and free movement of the fingers.

•ARC FLASH SUIT: use to protect our whole body from this electrical hazard

•High Temperatures near the body produced by an electric arc or explosion cause Arc or Flash Burns. They should also be attended to promptly.

•Thermal Contact Burns occur when skin comes in contact with overheated electric equipment, or when clothing is ignited in an electrical incident.

Source: OSHS & DOLE-OSH Training Material

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WHAT EQUIPMENT MUST BE LABELED?

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Safety Practices: One-Hand Rule

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Safety Practices: One-Hand Rule

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NFPA 70-2012, 130.6(H)

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130.7(C) PERSONAL PROTECTIVE EQUIPMENT

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240-V LIVE PANELBOARD

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ARC FLASH HAZARD CALCULATION

The ff examples break down the calculations and compare the Hazard Risk Category (HRC), Incident Energy (cal/cm2), Flash Protection Boundary (FPB) and PPE (Personal Protective Equipment) required to work on an energized 480V system protected by either 2500 Amp Class L fuses or a 2500 Amp LV power circuit breaker.

Source: LittlelFuse Electrical Safety Hazards Handbook

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ARC FLASH HAZARD CALCULATION

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ARC FLASH HAZARD CALCULATIONS

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Documents

RME Arc Flash Hazards Awareness