1. High Voltage Electrical Safety
The Shocking Truth

2. Course Objective Regulation OSHA and NFPA 70E
Qualified Person Unqualified Person
Level of Hazards (Hazard Classification and Category)
Location Planning and Procedures
Approach Limits
Lockout and Energized Electrical Permitting
Insulated Equipment and Tools
Personal Protective Equipment (Arc Flash and Blast rating)

3. Objective Continued Special Precautions Electrical Diagrams
Equipment Details
Examples of Equipment

4. Arc Flash Hazards
Every year, more than 2,000 workers are treated in burn centers with severe arc flash injuries. The flash is immediate, but the results can cause severe injuries that last months, years—even a lifetime. In some cases, they may cause death.
Fortunately, arc flash hazards can be reduced by following safety precautions and using the recommended personal protective equipment.

5. What is an arc flash hazard?
Think of an arc flash as a short circuit through the air. In an arc flash incident, an enormous amount of concentrated radiant energy explodes outward from electrical equipment.
The explosion creates pressure waves that can damage a person’s hearing, a high-intensity flash that can damage their eyesight and a superheated ball of gas that can severely burn a worker’s body and melt metal.
The pressure waves can also propel loose material like molten metal, pieces of damaged equipment, tools and other objects, through the air.

6. Where do arc flash hazards occur?
A hazardous arc flash can occur in any electrical device, regardless of voltage, in which the energy is high enough to sustain an arc. Potential places where this can happen include:
Panel boards and switchboards
Motor control centers
Metal clad switch gear
Transformers
Motor starters and drive cabinets
Fused disconnects
Any place that can have equipment failure

7. Who is at risk?
Some of the employees at risk from arc flash hazards include mechanics, electricians and HVAC personnel. The most dangerous tasks include:
Removing or installing circuit breakers or fuses
Working on control circuits with energized parts exposed
Racking circuit breakers in and out of switch gear
Applying safety grounds
Removing panel covers
Low voltage testing and diagnostics

8. What are the effects of an arc flash explosion?
The effects of an arcing fault can be devastating. The intense thermal energy can cause severe burns in a fraction of a second.
One of the major causes of electrical burns and deaths to workers is ignition of non-fire rated clothing due to an arcing fault. Treatment can require years of skin grafting and rehabilitation. A victim may never return to work or enjoy quality of life. Treatment costs can exceed $1,000,000 per case.
Other considerations include loss of life, potential litigation fees, loss of process, potential fines and escalation of insurance premiums.

9. Did you know?
The temperature of an arc flash can reach 35,000 degrees Fahrenheit – about four times as hot as the surface of the sun.

16. How can we reduce the risk:
Understand how to reduce the probability of an arc flash event and its effects.
By begin with an Arc Flash Analysis and Assessment that includes:
Potential arc flash incident energy levels
Flash protection boundary distances
Safety training
Selecting the correct personal protection equipment (PPE)
Proper Electrical equipment labeling

17. Electrical Safety-Related Work Practices
If electrical equipment must remain energized while servicing and maintenance is performed, electrical safety-related work practices must be utilized by qualified employees as outlined by OSHA in 29 CFR – In addition to OSHA’s requirements, NFPA 70E Standard for Electrical Safety in the Workplace 2004 Edition contains requirements for performing a flash hazard analysis.

19. Flash Hazard Analysis and Flash Protection Boundary
Prior to commencing work on electrically energized conductors > 50 volts, NFPA 70E Article requires that a flash hazard analysis be performed to identify work tasks that must be performed while electrical equipment remains energized. Instead of performing a detailed analysis, however, Table (C)(9)(A) (Hazard Risk Category Classifications) may be utilized to identify various job tasks and the corresponding hazard risk category.
NFPA 70E Article (A) requires employers to establish a flash protection boundary – a distance from exposed energized electrical parts at which an employee could sustain a second degree burn if an electric arc flash were to occur. Employees performing work on energized conductors inside this boundary must be protected with appropriate Personal Protective Equipment (PPE). In most cases, the flash protection boundary for electrical systems 600 volts and below will be four (4) feet.

22. What are the NFPA 70E Guidelines?
An employer is required to:
Conduct an arc flash hazard analysis of the workplace.
Implement qualified and general worker safety training based on the arc flash hazard analysis results.
Establish shock and flash protection boundaries.
Provide protective clothing (PC) and personal protective equipment (PPE) that meet ANSI standards.
Put warning labels on equipment (see example at right). A future edition of the arc flash safety code may require more extensive labeling (inset) that includes flash hazard boundary and PPE levels.

23. Arc Flash Marking on Field Breakers
In addition to the flash hazard analysis and PPE requirements specified in NFPA 70E, the 2002 National Electrical Code® (NEC) requires field labeling of circuit breaker panels and electrical disconnects to warn qualified employees of the potential arc flash hazards:
Article Flash Protection: "Switchboards, panel boards, industrial control panels, and motor control centers in other than dwelling occupancies, that are likely to require examination, adjustment, servicing, or maintenance while energized, shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment." An example of an arc flash label is shown.

24. (including voltage testing) rated < 240 volts.
Selection of Personal Protective Equipment NFPA 70E Table (C)(9)(A) lists various work tasks and the corresponding hazard risk category (0 through 4). Once the hazard risk category has been determined, Table (C)(10) [Protective Clothing and Personal Protective Equipment (PPE) Matrix] is consulted to determine the appropriate PPE. An example is listed below. Example: Employee is working on an energized panelboard
(including voltage testing) rated < 240 volts.
Required PPE: Task is listed as a hazard risk category one (1). In addition to voltage rated gloves, Table (C)(10) specifies the following PPE: Flame retardant clothing (long-sleeve shirt and pants), hard hat and safety glasses.

25. Other Personal Protective Equipment

26. Jackets
Hard Hat
Shield
Gloves Tested 00
Gloves Leather

27. Insulated Tools

28. Meters & Testers

29. Types of Electrical Boxes
480 volt Switch Gear

31. Open/close pushbuttons permit local electrical operation.
                                                                                                                          
Open/close pushbuttons permit local electrical operation.
Dual-purpose manual handle for charging and tripping switch operators when control power is not available.
Operator targets show switch operator status (charged or discharged) and position (open or closed).
Optional remote-control receptacle for attaching remote-control station. Permits open-close operation from adjacent area.
Charging shaft for manual charging in the event power is lost.
Switch-position target indicates whether Mini-Rupter® Switch is open or closed.
Decoupler indicator shows whether switch operator is coupled to Mini-Rupter Switch.
Decoupler handle permits convenient decoupling of switch from switch operator for functional testing of source-transfer schemes and exercising of switch operator, without disturbing power circuit.
Bolted covers provide access to input connectors and receptacles, and terminal blocks.
 Micro-AT® Source-Transfer Control

32. E-Vault

33. Dry Transformer

34. Power Closet

35. 480 Switch Gear

36. Disconnect found during Infrared Inspection
Disconnect found during Infrared Inspection. Failed due to loose connection inside the switching mechanism. Switch was found to be in the energized state

37. Cover Completely
Blown Off

38. Summary Arc flash hazards pose a serious risk to employee safety; proper safe work practices must be utilized. Electrical equipment > 50 volts must be deenergized and lockout/tagout followed prior to servicing and maintenance unless doing so would increase hazards or is infeasible. Remember, convenience is not an acceptable reason for keeping equipment energized during servicing and maintenance. If electrical equipment must remain energized during servicing and maintenance, NFPA 70E should be consulted to determine flash hazard boundaries as well as required PPE. Finally, circuit breakers and electrical disconnects must be marked to warn qualified employees of potential arc flash hazards.
For more information on electric arc flash hazards or assistance on performing a flash hazard analysis, please contact W. Jon Wallace, CSP, MBA