Electrical SafetySafety Unit Lesson 6

Electricity

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.

Electric Current

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.

Electricity

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

Welding related Electrical Hazards

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.

Electricity

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.

Welding related Electrical Hazards

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.