Module 3 Electrical Hazards Harwood Crant 46 J

Module 3 Electrical Hazards Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 1

Let’s start with a few case histories “An employee was electrocuted while using a grinder with a frayed cord. The employee was standing in water, wet-grinding stone countertops…” Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 2

“A maintenance employee was electrocuted while attempting to change a light fixture…” (no Lockout/Tagout) “An employee was electrocuted when he made contact with a piece of equipment being hoisted from an excavation. The arm of the backhoe hoisting the equipment contacted an overhead power line…” Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 3

Top Electrical Citations (FY 2005) Electrical, Wiring Design and Protection Elec. Wiring Methods, Components and Equipment, General Use Electrical, General Requirements Electrical, Safety-Related Work Practices, General Requirements Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 4 Source: Citation statistics from Federal OSHA data for OSHA fiscal year 2005

Causes of Electrocution Fatalities • • • Contact with Overhead Power lines Contact with Live Circuits Not following Lock/Tagout procedures Poorly Maintained Extension Cords Defective Power Tools Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 5

Electrical Injuries There are three direct and two indirect types of electrical injuries: • Direct: ØElectrocution or death due to electrical shock ØElectrical shock ØBurns • Indirect: ØFalls ØFire Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 6

Shock Severity • Severity of the shock depends on: – Path of current through the body – Amount of current flowing through the body (amps) – Duration of the shocking current through the body, • LOW VOLTAGE DOES NOT MEAN LOW HAZARD Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 7

Overhead Power Lines Hazard • Usually not insulated • Examples of equipment that can contact power lines: – – – – Crane Ladder Scaffold Backhoe Scissors lift Raised dump truck bed Aluminum paint roller Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 8

It’s Your Job to Know! ü ü ü Know the hazards of electricity Know the equipment Use Safe Work Practices Inspect your PPE before each use Don’t work on energized circuits without permission Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 9

Safety-Related Work Practices To protect workers from electrical shock: – Use barriers and guards to prevent passage through areas of exposed energized equipment – Pre-plan work, post hazard warnings and use protective measures – Keep working spaces and walkways clear of cords Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 10

“An employee working on a roof made contact with the service entrance riser into the home and was electrocuted…” Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 11

Caution • Special Training is required for work on electrical equipment. Such training is for Authorized Employees and it covers: – Safe Work Practices – Isolation of Electrical Sources – Test Equipment – Tools & PPE • Only Authorized Employees may conduct electrical work Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 12

Control Devices Control circuit devices such as… – push buttons – selector switches – interlocks … may not be used as the sole means for de-energizing circuits or equipment. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 13

Control – Use GFCI (ground-fault circuit interrupter) • Protects you from shock • Detects difference in current between the black and white wires • If ground fault detected, GFCI shuts off electricity in 1/40 th of a second • Use GFCI’s on all 120 -volt, singlephase, 15 - and 20 -ampere receptacles, or have an assured equipment grounding conductor program. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 14

ELECTRICAL SAFETY Effects of Amount of AC Current ma=1/1000 th of an amp • 3 ma- painful shock which cause indirect accidents • 10 ma- muscle contraction. . . ”no let go” danger • 30 ma- lung paralysis- usually temporary • 50 ma- possible ventricular fibrillation (heart dysfunction, usually fatal) • 100 ma- certain ventricular fibrillation, fatal • 4 amps- heart paralysis, severe burns Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 15

How it works Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 16

Are these safe practices? Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 17

Lock & Tag • Lock & Tag all Sources – Place Lock & Tag on each disconnecting means used to de-energize circuits – Attach lock to prevent operating the disconnecting means – Place Tag with each lock Note: Only the person who places the lock may remove it. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 18

Lockout Devices Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 19

If a Lock cannot be applied… • A tag used without a lock must be supplemented by at least one additional safety measure that provides a level of safety equal to that of a lock. • Examples: – Removal of an isolating circuit element such as a fuse – Blocking of a controlling switch – Opening of an extra disconnecting device. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 20

Tagout There many different kinds of tags and Lockout devices. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 21

Release Stored Energy • Stored electric energy must be released before starting work. – Discharge all Capacitors – Short-Circuit & Ground all high capacitance elements Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 22

Is it “Dead”? • Verify System is Deenergized – Operate the equipment controls to check that equipment cannot be restarted. Use test equipment to test the circuits & electrical parts for voltage & current Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 23

Alerting others of hazards v Use barricades to prevent or limit access to work areas with un-insulated energized conductors or circuit parts. v Use safety signs, safety symbols, or accident prevention tags to warn others about electrical hazards which may endanger them. v If signs and barricades do not provide sufficient warning and protection from electrical hazards, an attendant shall be stationed to warn and protect employees. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 24

Electrical Tools and Cords Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 25

Portable Electric Tools & Cords • Portable equipment must be handled in a manner which will not cause damage. • Flexible electric cords connected to equipment may not be used for raising or lowering the equipment. • Flexible cords may not be fastened with staples or otherwise hung in such a fashion as could damage the outer jacket or insulation. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 26

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 handlines used near exposed energized parts must be nonconductive. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 27

Power Tool Requirements • Have a three-wire cord with ground plugged into a grounded receptacle, or • Be double insulated, or • Be powered by a low-voltage isolation transformer Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 28

Preventing Electrical Hazards Tools • Inspect tools before use • Use the right tool correctly • Protect your tools • Use double insulated tools Double Insulated marking Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 29

Any problems? Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 30

Clues that Electrical Hazards Exist • Tripped circuit breakers or blown fuses • Warm tools, wires, cords, connections, or junction boxes • GFCI that shuts off a circuit • Worn or frayed insulation around wire or connection Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 31

Beware of Old Wiring • Removal of expansion tank (hot water). • Old style knob electrical wiring. • Victim contacted frayed wiring. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 32

Wire Pulling • Avoid manual wire pulling and use a tugger or a handtool whenever possible • Communication between the puller and feeder to coordinate movements will make the job easier and safer. • Use lighter-weight tools. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 33

Reducing Body Strains • CHANGE BODY POSITIONS. • Working overhead, at floor level, or in cramped spaces forces the body into awkward postures. • To relieve muscle tension and improve circulation, change body positions, alternate tasks, and stretch throughout the day. Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 34

Summary Electrical equipment must be: – Listed and labeled – Free from hazards – Used in the proper manner If you use electrical tools you must: – Be protected from electrical shock – Use them in a comfortable position – Be provided with necessary safety equipment Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 35

“A tree trimmer was electrocuted when he touched an overhead electrical line while descending a palm tree…” Always remember… It’s your life! “An employee was electrocuted while working on an A/C unit…” Harwood Crant #46 J 6 -HT 13 Rev. 011507 Southwest Safety Training Alliance Inc 36