Electrical Safety Preventing Shock and Fire Electrical Shock

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Electrical Safety Preventing Shock and Fire

Electrical Safety Preventing Shock and Fire

Electrical Shock! n n n To receive a shock, there must be a difference

Electrical Shock! n n n To receive a shock, there must be a difference in voltage between one part of your body and another part. Electron flow will pass along the path of least electrical resistance connecting these two points. So Electric Shock occurs when current is produced in the body, which is caused by an applied voltage.

Factors contributing to death from electrical shock: n. Current n n (amperage) kills, not

Factors contributing to death from electrical shock: n. Current n n (amperage) kills, not voltage Voltage is involved Less than ¼ ampere will stop the heart (current flowing in a 25 -watt lamp at 115 volts is enough to stop the heart of an average man)

Factors (cont) q ü q q Ø Ø ü You have to touch two

Factors (cont) q ü q q Ø Ø ü You have to touch two different things with different voltages Bird on a high-voltage wire The damaging effects of shock result from current through the body. A person’s resistance ranges from about 100 ohms (soaked with salt water - pure water is not a good conductor) to about 500, 000 ohms (skin very dry) Dry fingers at 100, 000 ohms touch terminals of 12 volt battery Ohms Law 12 V / 100, 000 Ω =. 00012 A (usually cannot feel)

Effect of Electric Current on the Body Current (A) Ø Ø Ø . 001.

Effect of Electric Current on the Body Current (A) Ø Ø Ø . 001. 005. 010. 015. 070 Ø Ø Ø Effect_______ Can be Felt Is painful Causes involuntary muscle contractions (spasms) Causes loss of muscle control If goes through the heart; serious damage, probably fatal if current lasts for more than 1 second

Five Major Causes of Electrical Accidents n n n Carelessness Misuse Improper wiring Lack

Five Major Causes of Electrical Accidents n n n Carelessness Misuse Improper wiring Lack of knowledge Water

Helping a Shock Victim n 1. 2. 3. n n n Injury by electric

Helping a Shock Victim n 1. 2. 3. n n n Injury by electric shock: Burning of tissues by heating Muscle Contraction Disruption of cardiac rhythm If you cannot shut of the power IMMEDIATELY, try instead, to move the person from contact with the electricity. Use great care that you do not receive a shock yourself. Use a stick or insulated material to move the conductor or the victim. Follow First Aid Emergency Action Principles

Basic Safety Rules n n n n Remain alert always. THINK before you act.

Basic Safety Rules n n n n Remain alert always. THINK before you act. Avoid quick movements. Work slowly and deliberately. NEVER work on live wires. (Make sure off in 2 Places) Never assume that the circuit is de-energized(dead). Test it with a test light before you start to work. Use proper tools (insulated handles) Do not wear metal objects when working on electrical devices. Remove jewelry, rings, watches, and any other metallic apparel from the body. Make sure that all electrical equipment is properly grounded. Do not wear clothing that is floppy. Loose clothing will catch on corners and rough surfaces causing unsafe motion.

Types of Protection Devices v Electrical Equipment Ø Ground Plugs – grounds the equipment

Types of Protection Devices v Electrical Equipment Ø Ground Plugs – grounds the equipment by conducting away unwanted current. v Circuit Protection Devices Ø Fuses Blade Cartridge Plug – Edison Base, Type S Accessory n Circuit Breakers – magnets or bimetallic strips to open a switch Ø Ø Ø q Single Pole Double Pole GFCI – Ground Fault Circuit Interruptors