ELECTRICAL SAFETY

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ELECTRICAL SAFETY

Gerald P. Robinson Jr., P.E. – Hatch Mott MacDonald

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· Electrical Safety Statistics– Annually about 8000 electrical injuries are sent to hospitals.– Over 2000 workers are sent to burn centers from electrical related injuries– One person is killed by electrocution in the U.S. each day.– Approximately 2/3 of the workers killed by electrocution were not electrical

workers.

Electrical Safety in the Municipal Water and Wastewater Environment

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• Results of a Safety Survey conducted by NFPA– Survey of 1200 electricians:

• 97% had experienced an electrical shock• 26 had witnessed an electrical injury• 58% were exposed to the possibility of an electrical

injury every day


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• Electrical Safety in the United States Based on Three Principals– All Electrical Equipment and Conductors shall be Listed/Labeled and

Acceptable for Safe Electrical Operation– All Electrical Equipment and Conductors shall be installed in accordance with

Nationally Accepted Codes and Standards– All Electrical Equipment and Conductors shall be Operated & Maintained in

accordance with Nationally Accepted Safety Standards


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• Listed/Labeled and Acceptable Equipment– National Electrical Code (NEC) requires equipment and conductors to be

“Acceptable to the authority having jurisdiction (AHJ)”• Listed / Labeled by an Nationally Recognized Testing

Laboratory (NRTL) • Evaluated by the AHJ and determined to be “Acceptable”

– OSHA – 29CFR 1910.303 and 29CFR 1910.399• Electrical equipment is acceptable only if it is listed,

labeled, or certified as safe by a NRTL


g• Effects of Sandy on NRTL Listed & Labeled

Electrical Equipment– Did the NRTL listing remain in force after the electrical

equipment was submerged in saltwater? (Listing Agency is UL for this equipment)

• “…the answer to the above questions is that the Listing on the equipment can no longer be considered valid, since the equipment was subjected to a condition of being submerged in water with other contaminants or exposed to significant damp conditions that were not within the equipment or component listing. “ (UL Field Evaluation of a piece of submerged electrical equipment from Sandy)


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• Installed in accordance with Nationally Accepted Codes and Standards (sample of a few codes)– National Fire Protection Association

• NFPA 70 – The National Electrical Code• NFPA 820 – Standards for Fire Protection in Wastewater

Treatment and Collection Facilities– Great Lakes Upper Mississippi Board of State Public Health and

Environmental Managers• Recommended Standards for Wastewater Facilities• Recommended Standards for Water Works


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• Operated & Maintained in accordance with Nationally Accepted Safety Standards– OSHA - General Duty Clause states that an employer must protect its

employees from recognized hazards. – NFPA 70E – Standard for Electrical Safety in the Workplace


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• NFPA 70E – Standard for Electrical Safety in the Workplace– In 1976 OSHA and NFPA began working together to address electrical

safety in the workplace

– In 1979 the first edition of NFPA 70E “Standard for Electrical Safety Requirements for Employee Workplaces” was published

– NFPA 70E has become the “STANDARD” for Electrical Safety in the Workplace and is used by OSHA to evaluate electrical safety in the workplace using the General Care Standard


gElectrical Safety in the Municipal Water and Wastewater Environment

· Responsibilities– The “Employer” is responsible for:

• Electrical Safety Program– Up to date drawings and diagrams– Arc Flash Analysis (updated every 5 years)– Lockout / Tagout

• Safety Policies and Procedures• Safety Training and Retraining• Personal Protective Equipment(PPE)

– The “Employee” is responsible for:• Following procedures established by the “Employer”• Wearing Employer Provided PPE

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• Basic Electrical Hazards in the Workplace– Shock Hazard: A dangerous condition associated

with the possible release of energy caused by contact or approach to energized electrical conductors or circuit parts.

– Arc Flash Hazard: A dangerous condition associated with the possible release of energy caused by an electrical arc.


g· OSHA & NFPA 70E Each have

Requirements for Working on ‘Live’ Equipment

– Qualified electrical workers shall not be asked to work on equipment that is “hot” or “live” except for two demonstrable reasons:• De-energizing introduces

additional or increased hazards (e.g.* cutting ventilation to a hazardous location* emergency alarm systems or)

• Infeasible due to equipment design or operational limitations (e.g.* voltage testing for diagnostics * start up testing)


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• Operations– Circuit Breakers in Panelboards or Motor Control Centers with the covers

closed rated 600V and below (Cat 0 PPE)

– Motor Starters in Motor Control Centers and Individual Enclosures with the covers closed rated 7.2kV and below (Cat 0 PPE)

– Opening hinged covers to expose energized electrical conductors or parts on equipment rated 240V or below (Cat 0 PPE)


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• Cat 0 PPE – (Natural Fiber Clothing)

• Long Sleeve Natural Fiber Shirt• Natural Fiber Long Pants• Safety Glasses• Hearing Protection• Leather Gloves


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• Operations– Energized Work on parts and conductors in equipment operating

between 240V - 600V (Cat 2 PPE)

– Circuit Breaker Operation on metal clad switchgear with the door closed rated 1kV through 38kV (Cat 2 PPE)

– Work on 120V Control Circuits in metal clad switchgear rated 1kV through 38kV (Cat 2 PPE)


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• Cat 2 PPE – (Min Arc Rating of 8 cal/cm2)

• Arc Rated long sleeve shirt• Arc Rated pants or coveralls• Arc Rated Face Shield • Hard Hat• Safety Glasses• Hearing Protection• Leather Gloves• Leather Work Shoes


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• Operations– Removal of Bolted Covers on energized MCCs operating at 600V and

below (Cat 4 PPE)

– Insertion or Removal of a Energized MCC Bucket on MCCs operating at 600V and below (Cat 4 PPE)

– Work on Control Circuits Greater than 120V in metal clad switchgear rated 1kV through 38kV (Cat 4 PPE)

– Circuit Breaker Operation with door open on metal clad switchgear rated 1kV through 38kV (Cat 4 PPE)


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• PPE – Category 4 (Min Arc Rating of 40 cal/cm2)

• Arc Rated Coveralls or Flash Suit• Arc Rated Flash Suite Hood• FR Hardhat Liner• Hard Hat• Safety Glasses• Hearing Protection• Arc Rated Gloves• Leather Work Shoes


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• Traditional Duplex Pump Control Panel– Inner Door only designed to

provide Voltage Protection – No Arc Flash Protection

– Outer Door to be opened by Qualified Persons Only

– Typical PPE Required (arc flash analysis required)

• Cat 0 to open outer door• Cat 2 to open inner door


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Effective Electrical Safety Program Needs to Include:• Management Commitment to

De-Energize all Electrical Equipment for Service

• Up to Date Electrical Drawing• Arc Flash Analysis • Employee Training• Personal Protective Equipment


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Questions ?


ELECTRICAL SAFETY

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