Energized Work PAUL RILEY, CSP
EXPECTATIONS • What do you expect to get out of this class?
HURT AT WORK! “I’ve been doing it this way for 20 years and ain’t been hurt yet.”
Introduction • An average of one worker is electrocuted on the job every day • Forth leading cause of death in the workplace today. • Approximately 1000 Electrocutions per year. • OSHA Citations Issued for 70% of all workplace electrocutions.
The Four Hazards of Electricity • Shock • Arc Has only become a recognized hazard of electricity in the last 4 years. NFPA 70E was the first standard to recognize and take steps to minimize arc hazards. • Flash • Blast • Burn • Fire Ignition The incidence of fire ignition has dropped dramatically since the advent of the NEC and the acceptance of the installation requirements within the industry. The NEC does not concern itself primarily with the other three hazards of electricity.
Electrical Shock • Received when current passes through the body. • Severity of the shock depends on: • Path of current through the body • Amount of current flowing through the body • Length of time the body is in the circuit • LOW VOLTAGE DOES NOT MEAN LOW HAZARD
Electrical Burns • Entrance Wound: High resistance of skin transforms electrical energy into heat, which produces burns around the entrance point (dark spot in center of wound). This man was lucky; the current narrowly missed his spinal cord
Immediate Heart Muscle contraction Tingling Pain Breathing Disorientation Dizziness Long term Memory Loss Nervous disorders Chemical imbalances Damage to heart muscle Electric Shock
Electrical Burn • Exit Wound: • Current flows through the body from the entrance point, until finally exiting where the body is closest to the ground. This foot suffered massive internal injuries which weren't readily visible, and had to be amputated a few days later.
Electrical Shock • Dangers of Electrical Shock • Currents greater than 75 mA* can cause ventricular fibrillation (rapid, ineffective heartbeat) • Will cause death in a few minutes unless a defibrillator is used • 75 mA is not much current – a small power drill uses 30 times as much Defibrillator in use * mA = milliampere = 1/1,000 of an ampere
Blast Electrical arc burns at 37,000 degrees F. 4 times the surface of the sun 2 times the center of a nuclear explosion Flash Ultra-violet light Temporary to permanent blindness Arc Welding Sun burn Arc – Two Dangers
Arc or Flash Burns • This man was near a power box when an electrical explosion occurred. Though he did not touch the box, electricity arced through the air and entered his body. The current was drawn to his armpits because perspiration is very conductive.
Surface Burns Caused by entrance and exit of electrical currents through the body Can be caused by a very small amount of current 1st degree to 3rd degree Tissue Burns Caused by current flowing through organs of the body Caused by currents in excess of 4 amps 3rd degree Internal organs Typically fatal Burns – Two Types
BURNS • Electrical Burns • Most common shock-related, nonfatal injury • Occurs when you touch electrical wiring or equipment that is improperly used or maintained • Typically occurs on the hands • Very serious injury that needs immediate attention
Electrical Burn • Internal Injuries • This worker was shocked by a tool he was holding. The entrance wound and thermal burns from the overheated tool are apparent.
Electrical Burn • Same hand a few days later, when massive subcutaneous tissue damage had caused severe swelling (swelling usually peaks 24-72 hours after electrical shock). To relieve pressure , which would have damaged nerves and blood vessels, the skin on the arm was cut open.
Ranking • Rank the following 4 categories of electrical work by their hazard potential. The most dangerous would be ranked 1, the least dangerous 4. • Transformer and Panelboards, Switchgear • Overhead Power Lines • J-boxes located above 8’ • J-boxes located below 8’
University Of San Diego Study • Overhead Power Lines 3% • Panel boards and Transformers 8% • J-boxes located above 8’ 68% • J-boxes located below 8’ 21% • WHY?
NFPA - Background • The original and primary mission of NFPA • Primarily covered by installation standards contained in the National Electric Code and NFPA 70 • The incidence of fire ignition has dropped dramatically since the advent of the NEC and NFPA and the acceptance of installation requirements within the industry.
NEC - Background • The NEC is intended for use primarily by those who design, install, and inspect electrical installations. • Requirements for electrical safety-related work practices and maintenance of the electrical system considered critical to safety are not found in the NEC. • The National Electric Code protects individuals from shock hazards under normal conditions. • It is not designed to protect us from abnormal conditions • We need additional policies to protect from abnormal conditions
NEW NEC REQUIREMENT New NEC Requirement The 2002 National Electrical Code has added Section 110.16, Flash Protection. Switchboards, Panel boards, Industrial Control Panels, and Motor Control Centers that are likely to require examination, adjustment, servicing, or maintenance while energized shall be marked to warn qualified persons of potential arc flash hazards. The marking shall be located to so as to be clearly visible to qualified persons before examination, adjustment servicing, or maintenance of the equipment. JUST ANOTHER REMINDER TO WEAR YOUR PPE
What is NFPA – 70E? • Published by the National Fire Protection Association, NFPA 70E was written to protect electrical workers in every industry around any type of device capable of generating an arc flash.
Who is Affected? • Virtually any facility housing electrical equipment falls under its guidelines. • Within each organization there are maintenance workers, electricians, machine operators, or HVAC personnel that risk an electric arc flash around such equipment as meter banks, motor control centers and transformers.
1. Define Energized Work • Pretend you are the safety manager for a large electrical contractor. You must write a definition of “energized work” for your new policy manual. How would you define “energized work”. • Select a member of the group to present and defend your definition.
Energized Work Definition • “any work on electrical equipment, circuits, devices, systems, or any other energized part(s) where an employee is required to deliberately, or could accidentally, place any part of his body or any type of tool into or around such electrical devices where the voltage has been deemed to be in excess of 50 volts.”
NFPA 70-E • PART 1 – Installation Safety Requirements • General requirements for electrical installation • Wiring design and protection • Wiring methods • Specific purpose equipment and installations • Hazardous locations (Class 1 Div 1, etc.) • Special systems (Mobile equipment, fire alarm, etc.)
NFPA 70-E • PART II- Safety Related Work Practices • Training requirements • Electrical work practices • Personal and other protective equipment • Specific safety related equipment and work practices • Lockout/Tagout practices and devices (electrically safe) • Simple LOTO vs. Complex LOTO • Sample LOTO procedures
NFPA 70-E • PART III – Safety related maintenance requirements • General maintenance requirements • From enclosures to circuit breakers • Portable tools • Batteries and rooms
NFPA 70-E • Part IV – Safety requirements for specific equipment • Electrolytic Cells • Batteries and Battery Rooms • Lasers • Power Electronic Equipment
Energized Work Hazard Risk Class 0 WHAT IS THE PROPER PPE? • Hard hat – non-conductive and flame resistant. • Safety glasses or goggles. • Leather gloves. • Leather safety shoes (1,000 V insulating soles available). • Long pants – untreated natural fiber. • Shirt with long sleeves – untreated natural fiber. WHAT YOU CAN DO! • Operate switches, circuit breakers and starters with equipment covers on or doors closed on panels and switchgear through 600 V and MCCs through 7.2 kV. • Work on energized 120 V or below control circuits for above. • Operate CBs or fused switch with covers off in 240 V or below panel boards.
Energized Work Hazard Risk Class 1 WHAT IS THE PROPER PPE? (Above Class 0). • Fire retardant long sleeve shirt. • Fire retardant pants. • Fire retardant coveralls may be worn instead of the FR shirt and pants. WHAT YOU CAN DO! • Work on energized parts including voltage testing and remove/ install CBs or fused switches in panel boards rated <240 V. • Operate CBs, fused switches, or starters <600 V equipment and with doors open. • Bolted covers can be removed from 240 V panels and hinged covers can be opened on 600 V MCCs to expose bare, energized parts.
Energized Work Hazard Risk Class 2 WHAT IS THE PROPER PPE? (Above Class 1): • Short sleeve natural fiber T-shirt (under FR shirt or coveralls). • Long natural fiber pants (under FR pants or coveralls). WHAT YOU CAN DO! • Rack CBs in or out of 600 V and >1 kV switchgear, doors closed. • Open hinged covers on 600 V switchgear exposing bare, energized parts. • Operate CBs or fused switches in >1 kV switchgear or other >1kV equipment when doors are closed. • Work on 120 V and below energized control circuits in >1 kV switchgear. • Operate outdoor disconnect switch gang operated at grade on other equipment rated 1 kV and above. • Examine insulated cable in open area (voltage rated gloves and leather protectors required) .
Energized Work Hazard Risk Class 2* WHAT IS THE PROPER PPE? (Above Class 2). • Double layer switching hood. • Hearing protection (ear canal inserts). WHAT YOU CAN DO! • Work on energized parts, including voltage testing on any 600 V equipment (voltage rated gloves with leather protectors and voltage rated tools required). • Install safety grounds on any 600 V equipment (voltage rated gloves with leather protectors required). • Work on control circuits with energized parts >120 V exposed on any 600 V equipment (voltage rated gloves with leather protectors and voltage rated tools required). • Remove bolted covers to expose bare, energized parts on any 600 V equipment. • Operate up to 7.2 kV contactors with enclosure doors open
Energized Work Hazard Risk Class 3 WHAT IS THE PROPER PPE? (Above Class 2*). • Fire retardant hardhat liner. • Fire retardant coveralls. WHAT YOU CAN DO! • Insert or remove starter buckets from 600 V MCCs (voltage rated gloves with leather protectors required). • Rack CBs in or out of 600 V switchgear with doors open. • Remove bolted covers exposing bare, energized parts on 600 V switchgear. • Work on energized parts including voltage testing on 2.3 kV – 7.2 kV MCCs (voltage rated gloves with leather protectors and voltage rated tools required). • Work on control circuits with energized parts >120 V exposed on 2.3 kV – 7.2 kV MCCs (voltage rated gloves with leather protectors and voltage rated tools required).
Energized Work Hazard Risk Class 3 WHAT YOU CAN DO! (continued) • Install safety grounds on 2.3 kV – 7.2 kV MCCs (voltage rated gloves with leather protectors required) • Open hinged covers exposing bare, energized parts on 2.3 kV – 7.2 kV MCCs, 1 kV and above Metal Clad Switchgear, and on other equipment rated 1 kV and above • Open hookstick operated outdoor disconnect switch on other equipment rated 1 kV and above (voltage rated gloves with leather protectors and voltage rated tools required)
Energized Work Hazard Risk Class 4 WHAT IS THE PROPER PPE? (Above Class 3). • Flash suit jacket (2 layer). • Flash suit pants (2 layer). • Fire retardant coveralls are not required with flash suit. WHAT YOU CAN DO! • Remove bolted covers exposing bare, energized parts on 2.3 kV – 7.2 kV MCCs and 1 kV and above switchgear and other equipment. • On Metal Clad Switchgear 1 kV and above you can: • Operate CBs or fused switches with the enclosure doors open. • Work on energized parts, including voltage testing (voltage rated gloves with leather protectors and voltage rated tools required).
Energized Work Hazard Risk Class 4 WHAT YOU CAN DO! (continued). • Work on control circuits with energized parts >120 V exposed (voltage rated gloves with leather protectors and voltage rated tools required). • Rack CBs in or out of cubicles with doors open. • Install safety grounds, after voltage test (voltage rated gloves with leather protectors required). • Open voltage transformer or control power transformer compartments.
Energized Work Hazard Risk Class 4 WHAT YOU CAN DO! (continued). • On other Equipment 1 kV and above you can: • Work on energized parts, including voltage testing (voltage rated gloves with leather protectors and voltage rated tools required). • Remove bolted covers exposing bare, energized parts. • Examine insulated cable in manhole or other confined space (voltage rated gloves with leather protectors required).
Energized Work Safe Approach Distance(To Live Parts or Bare Energized Conductors) FLASH PROTECTION BOUNDARY -is the distance from a potential arc source within which a person may be exposed to a flash burn injury. Any person who crosses this boundary must be protected from exposure to arc flash. • Conservative distances based on Table B-1, Appendix B, NFPA 70E 2000 edition. • From Table 2-1.3.4, NFPA 70E, 2000 edition.
Energized Work Safety Program • Train employees to put into electrically safe mode first • Sell to the customer • Perform flash analysis or use a matrix • Submit permits ( if required by program ) • Inspect and don the appropriate PPE • Perform work energized. Again, only if necessary.
Program and Training • A sample Energized Work Program has been included. • Train employees once adopted. • Permit samples included to help sell the customer.
The Energized Work Matrix • The “Energized Work Matrix” is designed as a quick reference to assist you in selecting the proper PPE only. • It is not intended to replace NFPA 70E. • The matrix is based upon NFPA 70E. • Any tasks not covered or any confusion or questions should be resolved with NFPA 70E.
Tools & Equipment • Use insulated tools or handling equipment when working near exposed energized conductors or circuit parts. • Use fuse handling equipment to remove or install fuses when the fuse terminals are energized. • Ropes and hand lines used near exposed energized parts must be nonconductive.
PPE Inspections • Rubber protective equipment shall be visually inspected prior to use. In addition, an "air" test shall be performed for rubber gloves prior to use. • Electrical PPE with any of the following defects may not be used • A hole, tear, puncture, or cut • Ozone cutting or ozone checking (the cutting action produced by ozone on rubber under mechanical stress into a series of interlacing cracks) Don’t use defective Electrical PPE!
PPE Testing • Rubber insulating line hose: • Upon indication that insulating value is suspect. • Rubber insulating covers: • Upon indication that insulating value is suspect. • Rubber insulating blankets: • Before first issue and every 12 months • Rubber insulating gloves: • Before first issue and every 6 months • Rubber insulating sleeves • Before first issue and every 12 months
The Hard Part • The key to limiting the amount of energized work performed is to explain the process to the customer. • Remember: They already know it is dangerous. That’s why they called you. • Do they know it is dangerous for them?
Energized Work “It Couldn’t Happen to Me”