120 likes | 234 Views
Electrical Safety. Safety Unit Lesson 6. Electric shock from welding and cutting equipment can kill or cause severe burns by coming in contact with bare skin. Electricity. The outcome of an electric shock is determined by the amount of current that passes through the body .
E N D
Electrical Safety Safety Unit Lesson 6
Electric shock from welding and cutting equipment can kill or cause severe burns by coming in contact with bare skin. Electricity
The outcome of an electric shock is determined by the amount of current that passes through the body. The higher the voltage the greater the chance of a fatal shock. Electricity
When the term Current is used as a noun, it is referring to the flow or a stream. In electrical terms current is the flow of electricity from one point to another. One of those points is the source of electricity and the other is a ground. Electricity will not flow if there is no path to ground. Electric Current
There are two types of current used in welding Alternating Current (AC) and Direct Current (DC). Electric Current
There are two measures of electric current. • Voltage- Voltage is the measure of the electromotive force or pressure that causes current to flow. • Amperage- Amperage is the measurement of the electric current flowing though the circuit. Resistance to the flow of current is the cause of heat in an electric circuit. The greater the resistance, the greater the heat produced. Electric Current
Damp skin will increase the chance of an electric shock dramatically. Cuts or abrasions can also reduce resistance and increase shock potential. • Some guidelines regarding the seriousness of an electric shock: • Greater than 3 milliamps (mA)-indirect accident • Grater than 10 mA –Muscle contractions • Greater than 30 mA- Lung paralysis, usually temporary • Greater than 50 mA- possible ventricular fibrillation • 100 mA to 4A- Certain ventricular fibrillation • Greater than 4A- Heart paralysis, sever burns Electricity
Welding related electrical hazards come in two forms. The first form is called primary hazards, and they come form the voltage that powers the welding machine. This voltage is usually 230 or 460 volts. These potentials create the possibility of serious or even fatal shocks. It is important to know that this voltage exists inside the machine any time the machine is plugged in. Welding related Electrical Hazards
Secondary hazards exist in the welding process in itself. This type of shock can occur if a person touches a part of the electrode circuit, such as a bare spot on the electrode cable, and touches the metal part of the work material with another part of the body. Such a condition will occur if the welder is leaning against the work while welding. Welding related Electrical Hazards
The voltage is highest at the electrode when you are not welding. • Wear dry gloves when welding. • Keep welding cables and electrode holders in good condition. Electricity
Never operate arc welding equipment on wet or damp floors. • Never touch the electrode to a grounded surface, these surfaces will become electrically live. Electricity
Never operate arc welding equipment beyond its rated capacity. • Electrode holders, GTAW torches, and GMAW guns should not be left in contact with a grounded surface when not in use. Welding related Electrical Hazards