Common Electrical Hazards in the Workplace By Dan Klimek Sisk & Company

What we will cover today Qualified vs non-qualified workers Overview of why electricity is hazardous Portable generators vs utility supplied electricity Extension cords GFCI Overhead powerlines Breakers and related building installations

Qualified vs Non-Qualified “electrical” workers Qualified person: One who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved.

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 A small current that passes through the trunk of the body (heart and lungs) is capable of causing severe injury or electrocution. Low voltages can be extremely dangerous because, all other factors being equal, the degree of injury increases the longer the body is in contact with the circuit.

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

Falls Electric shock can also cause indirect or secondary injuries Workers in elevated locations who experience a shock can fall, resulting in serious injury or death

Portable Electric Generators Shocks and electrocution from improper use of power or accidentally energizing other electrical systems. Carbon monoxide from a generator’s exhaust. Fires from improperly refueling a generator or inappropriately storing the fuel for a generator. Noise and vibration hazards.

Flexible Cords 1910.305(g)(2)(i) Durably marked as to type, size, and number of conductors Strain relief must be provided Only cords with a secondary jacket can be used on job sites (standards specify the type of jackets) 1910.305(g)(2)(i) A conductor of a flexible cord or cable that is used as a grounded conductor or an equipment grounding conductor shall be distinguishable from other conductors. Types S, SC, SCE, SCT, SE, SEO, SEOO, SJ, SJE, SJEO, SJEOO, SJO, SJT, SJTO, SJTOO, SO, SOO, ST, STO, and STOO flexible cords and Types G, G-GC, PPE, and W flexible cables shall be durably marked on the surface at intervals not exceeding 610 mm (24 in.) with the type designation, size, and number of conductors.

Extension Cords The path to ground from circuits, equipment, and enclosures must be permanent and continuous Grounding prongs must be on the cords Inspect before use Protect cord from damage 1910.304(f)(4)

Splices 1910.305(g)(2)(ii) Flexible cords may be used only in continuous lengths without splice or tap. 1910.305(g)(2)(ii) Flexible cords may be used only in continuous lengths without splice or tap. Hard-service cord and junior hard-service cord No. 14 and larger may be repaired if spliced so that the splice retains the insulation, outer sheath properties, and usage characteristics of the cord being spliced. Note: Black electrical tape does not provide suitable insulation and is not acceptable

Flexible Cords 1910.304(b)(3)(ii)(C)(3) Extension cords must be visually inspected before each use on any shift. Examine the cord for: Missing grounding pin Damaged other jacket (tear in insulation) Possible internal damage (pinched cord) 1910.304(b)(3)(ii)(C)(3) Each cord set, attachment cap, plug, and receptacle of cord sets, and any equipment connected by cord and plug, except cord sets and receptacles which are fixed and not exposed to damage, shall be visually inspected before each day's use for external defects, such as deformed or missing pins or insulation damage, and for indications of possible internal damage. Equipment found damaged or defective shall not be used until repaired;

Flexible Cords – Permitted Use 1910.305(g)(1)(ii)(A)-(L) Pendants; Wiring of fixtures; Connection of portable lamps or appliances; Portable and mobile signs; Elevator cables; Wiring of cranes and hoists; Appliances to permit removal for maintenance and repair 1910.305(g)(1)(ii) Flexible cords and cables may be used only for:1910.305(g)(1)(ii)(A) Pendants;1910.305(g)(1)(ii)(B) Wiring of fixtures;1910.305(g)(1)(ii)(C) Connection of portable lamps or appliances;1910.305(g)(1)(ii)(D) Portable and mobile signs;1910.305(g)(1)(ii)(E) Elevator cables;1910.305(g)(1)(ii)(F) Wiring of cranes and hoists; 1910.305(g)(1)(ii)(I) Appliances where the fastening means and mechanical connections are designed to permit removal for maintenance and repair; Stationary equipment to facilitate interchange Pendant, or Fixture Wiring Portable lamps, tools or appliances

Prohibited Uses of Flexible Cords 1910.305(g)(1)(iv)(A)-(F) As a substitute for the fixed wiring of a structure; Where run through holes in walls, ceilings, or floors; Where run through doorways, windows, or similar openings; Where attached to building surfaces; Where concealed behind building walls, ceilings, or floors; or Where installed in raceways, except as otherwise permitted in this subpart. 1910.305(g)(1)(iv) Unless specifically permitted otherwise in paragraph (g)(1)(ii) of this section, flexible cords and cables may not be used:1910.305(g)(1)(iv)(A) As a substitute for the fixed wiring of a structure;1910.305(g)(1)(iv)(B) Where run through holes in walls, ceilings, or floors;1910.305(g)(1)(iv)(C) Where run through doorways, windows, or similar openings;1910.305(g)(1)(iv)(D) Where attached to building surfaces; Concealed behind or attached to building surfaces Substitute for fixed wiring Run through walls, ceilings, floors, doors, or windows

GFCI Protection 1910.304(b)(3)(i) Receptacles installed in bathrooms or on rooftops shall have ground-fault circuit-interrupter protection for personnel. 1910.304(b)(3)(i) All 125-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms or on rooftops shall have ground-fault circuit-interrupter protection for personnel.

Ground-Fault Circuit Interrupter This device protects you from dangerous shock If a ground fault is detected, the GFCI can shut off electricity flow in as little as 1/40 of a second, protecting you from a dangerous shock The GFCI continually matches the amount of current going to an electrical device against the amount of current returning from the device along the electrical path. Whenever the amount of current going differs from the amount returning by approximately 5 milliamperes, the GFCI interrupts the electric power within as little as 1/40 of a second, protecting you from a dangerous shock. GFCI’s are able to detect the loss of current resulting from leakage through a person who is beginning to be shocked. If this situation occurs, the GFCI switches off the current in the circuit. GFCI’s are different from circuit breakers and fuses because they detect leakage currents rather than overloads.

GFCI Protection 1910.304(b)(3)(ii)(A) Receptacle outlets (including cord sets) that are not part of the permanent wiring of the building shall have ground-fault circuit-interrupter protection for personnel. 1910.304(b)(3)(ii)(A) All 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets that are not part of the permanent wiring of the building or structure and that are in use by personnel shall have ground-fault circuit-interrupter protection for personnel. Note 1 to paragraph (b)(3)(ii)(A) of this section: A cord connector on an extension cord set is considered to be a receptacle outlet if the cord set is used for temporary electric power. Note 2 to paragraph (b)(3)(ii)(A) of this section: Cord sets and devices incorporating the required ground-fault circuit-interrupter that are connected to the receptacle closest to the source of power are acceptable forms of protection.

Arc Flash Event A dangerous release of energy created by an electrical fault Release will contain: Thermal energy Acoustical energy Pressure wave Debris

Lockout / Tagout The most effective and fool-proof way to eliminate the risk of electrical shock or arc flash is to simply deenergize the equipment. . .

Overhead Powerline Hazards Overhead powerlines are usually not insulated Keep all rig masts, drill steel, cranes, booms etc, away from powerlines If you get close to a powerline, electricity can flash over and be just as deadly as a direct contact Beware of powerlines when you work with ladders and scaffolding Overhead power lines must be deenergized and grounded by the owner or operator of the lines, or other protective measures must be provided before work is started. Protective measures (such as guarding or insulating the lines) must be designed to prevent contact with the lines. Minimum clearance distances for employees working in the vicinity of overhead power lines are given in 29 CFR 1910.333(c)(3). PPE may consist of rubber insulating gloves, hoods, sleeves, matting, blankets, line hose, and industrial protective helmets.

shall be legibly marked to indicate its purpose Labeling of Breakers 1910.303(f)(2) –(3) Overcurrent devices or disconnecting devices: shall be legibly marked to indicate its purpose shall be of sufficient durability to withstand the environment involved. 1910.303(f)(2) Services, feeders, and branch circuits. Each service, feeder, and branch circuit, at its disconnecting means or overcurrent device, shall be legibly marked to indicate its purpose, unless located and arranged so the purpose is evident. 1910.303(f)(3) Durability of markings. The markings required by paragraphs (f)(1) and (f)(2) of this section shall be of sufficient durability to withstand the environment involved.

Cabinets, Boxes and Fittings 1910.305(b)(2)(i) In completed installations, each outlet box shall have a cover, faceplate, or fixture canopy. 1910.305(b)(2)(i) All pull boxes, junction boxes, and fittings shall be provided with covers identified for the purpose. If metal covers are used, they shall be grounded. In completed installations, each outlet box shall have a cover, faceplate, or fixture canopy. Covers of outlet boxes having holes through which flexible cord pendants pass shall be provided with bushings designed for the purpose or shall have smooth, well-rounded surfaces on which the cords may bear

Hand-Held Electric Tools Hand-held electric tools pose a potential danger because they make continuous good contact with the hand To protect you from shock, burns, and electrocution, tools must: Have a three-wire cord with ground and be plugged into a grounded receptacle, or Be double insulated, or Be powered by a low-voltage isolation transformer Make sure generators are grounded and your cords are grounded back to the generator 1910.304(f)(5)(v)(C)(3) Hazards of portable electric tools: Currents as small as 10 mA can paralyze, or “freeze” muscles - Person cannot release tool - Tool is held even more tightly, resulting in longer exposure to shocking current Power drills use 30 times as much current as what will kill. Double-insulated equipment must be distinctly marked to indicate that the equipment utilizes an approved system of double insulation. The common marking is:

Let’s Review Qualified vs non-qualified workers Only do work you are trained to do Overview of why electricity is hazardous Shock, burns, falls, etc. Portable generators vs utility supplied electricity Make sure they are grounded Extension cords & GFCI Inspect before use and protect from damage Overhead powerlines Keep clearance Breakers and related building installations Need to marked, look for damage

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