Basic Electricity

Term Comparison Pressure Flow Back Pressure Hydraulic PSI GPM Resistance Back Pressure Hydraulic PSI GPM Electrical Volts Amps Ohms

Electrical pressure causes electric current to flow Voltage (Pressure) Electrical pressure causes electric current to flow

Ability of material to prevent electrons from flowing Resistance (Ohms) Ability of material to prevent electrons from flowing

Resistance Conductors - little resistance Metals Water Insulators - high resistance Rubber Dry wood Pottery Glass Porcelain

Human Resistance Body Area OHMS Dry Skin 600,000 Wet Skin 1,000 Internal Organs 500 Ear to Ear 100

Current Flow of electrons Measured in amps or milliamps (1/1000 of amp) Killing factor

Effects of Current 1 - 8 mA = Shock, not painful 8 - 15 mA = Pain 15-20 mA = Muscle contraction 20-100 mA = Severe pain & paralysis of breathing muscles 100-1000 mA = Ventricular fibrillation > 1,000 mA = Heart stops

60 watt bulb uses 1/2 amp (500 mA) 5 times current needed to kill 1 Amp = 1,000 Milliamps 60 watt bulb uses 1/2 amp (500 mA) AND 5 times current needed to kill

E I R Ohm’s Law E = Voltage (volts) I = Current (amperes) R = Resistance (ohms)

Fatalities at 50 Volts 50 Volts 50 Volts 1000 Ohm = .05 amps (50 mA)

Body Resistance Dry skin Ear to ear Hand to foot Wet skin 110V 350K Ohm = 1 mA Ear to ear 110V 100 Ohm = 1.1 A Hand to foot 110V 500 Ohm = 220 mA Wet skin 110V 1000 Ohm = 110 mA

100 mA for 3 seconds equals 900mA for .03 seconds Severity Of Shock Amps Path Duration 100 mA for 3 seconds equals 900mA for .03 seconds

Hazards Shock Burns Arcing