Electrical Safety for Welding 131

AC

Alternating current. Electrical current that reverses direction at regularly recurring intervals of time. In the United States, AC switches direction 60 times per second, or 60 hertz (Hz).

alternating current

AC. Electrical current that reverses direction at regularly recurring intervals of time. In the United States, alternating current switches direction 60 times per second, or 60 hertz (Hz).

American National Standards Institute

ANSI. A private, non-profit organization that administers and coordinates voluntary standards and systems. The American National Standards Institute writes nationally approved standards for the manufacturing industry.

amperage

The amount of current flowing through a circuit. Amperage is measured in amperes (A), or amps.

amperes

A. A unit of measurement that indicates the amount of current flowing in a circuit. Amperes are also called amps.

ANSI

American National Standards Institute. A private, non-profit organization that administers and coordinates voluntary standards and systems. ANSI writes nationally approved standards for the manufacturing industry.

ANSI Z49.1

A standards document published by the American National Standards Institute that covers welding PPE and other safety concerns. ANSI Z49.1 is titled "Safety in Welding, Cutting, and Allied Processes."

arc

The area in which electricity transfers between the electrode and the workpiece. The arc generates the heat that melts the base metals.

arc welding

A group of welding processes that use electricity to generate the heat needed to melt the base metals. Arc welding is portable and economical, making it the most common form of welding.

arcing

The flow of electricity through the air from one conductor to another. Arcing can be dangerous, especially when it occurs accidentally.

atom

A particle that makes up elements. An atom is the smallest distinguishable unit of an element that retains the element's characteristics.

blow

To interrupt an electrical circuit due to a melted component. Fuses blow when they detect excess current to prevent damage and injury.

body harness

A safety device composed of straps connected around the legs, waist, and shoulders that is attached to a hoist. A body harness may be required when working at elevated heights to prevent falls.

capacity

The amount of electricity that a conductor can carry safely. Capacity indicates how much current can flow through a device without it overheating.

circuit breakers

A device with a bimetallic strip that bends and flips a switch to open a circuit when it detects excess current. Circuit breakers open the circuit and stop current flow to prevent overheating.

circuits

A closed path through which electricity flows. Circuits consist of several different components connected by conductors.

class C fire extinguishers

A fire extinguisher that is approved for putting out fires caused by live electrical equipment. Class C fire extinguishers and multi-purpose fire extinguishers are the only extinguishers rated to put out fires caused by faulty wiring and overloaded circuits.

codes

A collection of laws or standards that outline practices for a particular application. Codes for electrical devices ensure safe operation.

compressed air

Air that has been forced into a small space at high pressure. Compressed air is often used to clean electronics.

conductors

A material that allows electricity to flow. Conductors are typically metals.

contact surfaces

A conductive part of a device that connects to other conductive components to allow electricity to flow between them. Contact surfaces connect points between conductors to create a closed circuit.

current

The flow of electricity through a circuit. Current strength is measured in amperes (A), or amps.

DC

Direct current. Electrical current that flows in one continuous direction. DC does not reverse the direction of flow.

diameter

The distance from one edge of a cable's cross section to the opposite edge. The diameter of a welding cable determines its current capacity.

direct current

DC. Electrical current that flows in one continuous direction. Direct current does not reverse the direction of flow.

disconnect switch

A switch on an electrical box or panel that cuts off power to a circuit within a facility. Disconnect switches are used to de-energize machines like welding power sources.

distribution system

An electrical circuit that provides power from the utility to specific end destinations. A distribution system uses generators, power lines, and transformers to deliver electric power to buildings and other structures.

duty cycle

The amount of time in a ten-minute period that an electrical device can operate at the rated current output before it must rest to prevent overheating. Duty cycle ratings are given as a percentage of the ten-minute period.

electric shock

The flow of electricity through the body. Severe electric shock can be fatal.

electrical box

A metal cabinet in a building where power from the electrical distribution system is distributed to circuits and devices throughout the building. An electrical box contains circuit breakers and/or fuses that automatically disconnect power if a fault occurs and may also have a manually operated disconnect switch.

electrical burn

A burn caused by the flow of electrical current through tissue or bone. Electrical burns most often occur on the hands.

electrical faults

A dangerous electrical condition that prevents current from completing its circuit as intended. Electrical faults include short circuits and open circuits.

electricity

A form of energy created by the movement of electrons. Electricity melts the base metals during arc welding.

electrode

A device that conducts electricity to the weld in arc welding. Electrodes may also serve as filler metal.

electrode cable

The path used in arc welding to conduct electricity between the power source and the electrode. The electrode cable attaches to a holder, welding gun, or torch that holds the electrode.

electrode holder

An insulated handle that clamps onto an electrode. The electrode holder is connected to the power source by the electrode cable.

electromagnetic field

EMF. The area in and around an energized conductor that exhibits electric and magnetic properties. Electromagnetic fields produce forces, the strength of which depends on the strength of the current.

electrons

A negatively charged particle that orbits the nucleus of an atom. Electrons flowing between atoms causes electricity.

EMF

Electromagnetic field. The area in and around an energized conductor that exhibits electric and magnetic properties. EMFs produce forces, the strength of which depends on the strength of the current.

enclosure

The metal frame or case of an electrical device such as a welding power source. The enclosure protects the wiring inside the power source.

fall protection

The use of various equipment to restrain employees from fall hazards or protect them when a fall occurs. Fall protection equipment includes safety nets, personal protective equipment (PPE), and other devices.

flame-resistant

FR. Designed to resist burning and withstand heat. Fire-resistant materials for PPE are rated and must meet specific safety standards.

fuses

A device with a metallic component that melts to open a circuit when it detects excess current. Fuses open the circuit and stop current flow to prevent overheating.

gas cylinders

A metal container used to store gases under pressure for manufacturing purposes. Gas cylinders are built specifically for each gas and have different properties depending on the gas.

grounded

Safely connected to an alternate return path for current in case a problem prevents it from returning like normal. Grounded equipment diverts current to prevent electric shock.

grounding

A means of providing a safe alternate return path for current that automatically disconnects power if a fault prevents current from flowing as intended. Grounding protects the electrical system and substantially reduces the risk of electric shock.

grounding conductor

The conductor that provides a low-resistance path to ground for fault currents. Grounding conductors are usually bare copper or covered with green insulation.

hot wires

A conductor that provides power to an electrical device or load. Hot wires are usually covered with black, red, or blue insulation.

input voltage

Electricity from an electrical distribution system that supplies power to electrical equipment. The input voltage, also known as the primary voltage, for a welding power source is higher than the voltage of the welding circuit.

insulation

A substance used to restrict the flow of electricity. Insulation can prevent electric shock when used properly.

insulators

A material that resists the flow of electricity. Insulators include rubber, plastic, wood, and ceramic.

lead

A conductor within a circuit or device that provides a path for electricity to flow between components. Leads inside the power source are electrically charged.

live

Electrically charged or energized. Live components carry electricity and present a risk of electric shock.

multi-purpose fire extinguishers

A fire extinguisher that is approved for putting out several different types of fires. Multi-purpose fire extinguishers, also called ABC fire extinguishers, are capable of putting out electrical fires.

National Electrical Manufacturers Association

NEMA. An organization that sets standards for electrical equipment used in the United States. The National Electrical Manufacturers Association also provides ratings for electrical devices.

National Fire Protection Association

NFPA. A non-profit organization that maintains standards of public safety and fire prevention and outlines the minimum safety requirements for electrical installations. The National Fire Protection Association produces the National Electric Code® (NEC®).

neutral wire

The conductor that returns power back to its source to complete a circuit. The neutral wire is usually covered with white insulation.

nonconductive

Unable to convey electricity. Nonconductive materials can be used as insulation in welding environments.

open-circuit voltage

OCV. The voltage of the welding circuit when the power source is energized but no welding is being performed. Open circuit voltage typically ranges from 20-100 volts.

pacemakers

An electronic medical device that is implanted in the chest to help control irregular or abnormal heartbeats. Pacemakers may malfunction in the presence of electromagnetic fields.

paralysis

Loss or impairment of the use of a body part or region of the body. Paralysis can be caused by electric shock.

personal protective equipment

PPE. Any clothing or device used to minimize exposure to hazards and prevent injury. Personal protective equipment includes welding helmets, long gloves, and safety footwear.

polarity

Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current flows.

power source

The device that provides the electricity needed to perform arc welding. The power source is energized by the input voltage supply.

PPE

Personal protective equipment. Any clothing or device used to minimize exposure to hazards and prevent injury. PPE includes welding helmets, long gloves, and safety footwear.

preventive maintenance

Regularly scheduled service and upkeep performed while a machine is still in working order. Preventive maintenance can prolong equipment life and increase production.

primary voltage

Electricity from an electrical distribution system that supplies power to electrical equipment. The primary voltage, also known as the input voltage, for a welding power source is higher than the voltage of the welding circuit.

primary voltage shock

An electric shock that originates from the input power supply. Primary voltage shocks are caused by simultaneously touching a lead inside an energized power source and another grounded object, such as the power source's enclosure.

resistance

The force that opposes the flow of electrical current. Resistance also affects voltage.

respiratory paralysis

Loss or impairment of the use of the respiratory organs. Respiratory paralysis prevents a person from breathing.

scaffolds

A temporary elevated platform consisting of metal or wooden crosspieces, supports or cables, and metal or wooden planking. Scaffolds allow welders to reach elevated workpieces and joints.

secondary voltage

Electricity from the welding power source that supplies power to the welding circuit. The secondary voltage is much lower than the input voltage delivered to the power source.

secondary voltage shock

An electric shock that originates from the electrical current in the welding circuit. Secondary voltage shocks are caused by simultaneously touching two components of the welding circuit, such as the electrode and the workpiece, when no welding is being performed.

short circuits

A condition that occurs when current takes a shorter, unintended path between two conductors, interrupting the intended flow of electricity. Short circuits cause excess current flow, which can destroy electronic components and cause fires and shock.

spatter

Liquid metal droplets expelled from the welding process. Spatter can leave undesirable dots of metal on a workpiece surface.

terminal

A connecting point in a circuit where a conductor can be attached to connect a component. Welding cables are connected to the output terminals of a power source.

thermal contact burns

A burn caused by fire or extreme heat. Thermal contact burns can be caused by touching faulty electrical equipment.

torch

An instrument used to generate the flame or arc for welding. The torch holds the electrode during arc welding and may also deliver shielding gas to the weld area.

trip

To interrupt an electrical circuit due to an automatically flipped switch. Circuit breakers trip when they detect excess current to prevent damage and injury.

ventricular fibrillation

Rapid and ineffective heartbeats. Ventricular fibrillation may lead to death within minutes unless a defibrillator is used.

voltage

The electrical force or pressure that causes current to flow in a circuit. Voltage is measured in volts (V).

volts

V. A unit of measurement that indicates the amount of electrical force or pressure in a circuit. Volts indicate voltage.

welding circuit

The output circuit of a welding power source. The welding circuit consists of a closed path connecting several components.

welding gun

A welding instrument that conducts electricity, guides the electrode, and, in some cases, releases shielding gas. Welding guns are used in some automatic and semi-automatic welding processes.

wire feeders

A device that delivers a supply of wire electrode to the welding gun. The wire feeder may be built inside the power source or be an external device set beside it.

work cable

The path used in arc welding to conduct electricity between the power source and the workpiece. The work cable connects to the workpiece via the work clamp.

work clamp

The component that connects the work cable to the workpiece. Work clamps are usually spring-loaded metal jaws that can fit workpieces of various shapes and sizes.

workpiece

A part undergoing some type of manufacturing process. The workpiece may be subject to cutting, welding, forming, or other operations.