The possibility of electric shock is one of the most serious risks encountered by a welder. Touching 'live' electrical components, including the electrode and the work piece, can result in serious a burn injury or, more seriously, electric shock.
Electric shock can kill, either by direct action on the body, or by a resultant fall, if working at height.
Most electrical accidents are avoidable and occur as a result of carelessness, lack of training, shoddy workmanship or due to faulty equipment. Welders must never become complacent about the hazards associated with electric arc welding and safe working practices should be followed at all times.
What Is It?
Electricity is a form of energy associated with the movement of electrons and protons in a conducting medium e.g. copper wire. The amount of electricity flowing is measured in 'amperes' and the pressure, or potential is measured in 'volts'. Electricity will only flow when a circuit is completed and a potential difference exists in the circuit.
Sources
In welding there are many sources of electrical hazard over and above those encountered in everyday life. These include the welding power plant, auxiliary welding equipment such as cables, wire feed units, welding torches and electrode holders plus other associated tools and equipment such as grinders and electrode ovens etc.
Serious injury can also result from contact with the welding circuit, and shocks from this source are probably the most frequently experienced by welders.
Increased hazard situations
If the welder is hot and perspiring, or if he or she is working in wet, damp, hot, humid or cramped conditions, the skin and clothing may become wet.
Effects of Exposure
The passage of an electric current through the body can cause severe injury and even death. The severity of the injury will depend on several factors including the actual current and voltage, the duration of current flow and how healthy the victim is.
Limits and Legislation
Welding equipment should be installed in accordance with international, national, or local standards and the manufacturer's instructions and tested to ensure it is correctly wired in, properly 'earthed', and safe to use.
Control and Prevention
Control of electrical hazards and prevention of electrical accidents should be paramount at all stages of a welding operation, from initial installation of the equipment, to its use and subsequent maintenance.
Regulations, many industry codes of practice and safety guidance documents have been issued over the years regarding the safe use of electrical equipment and protective clothing to be worn when welding.
Installation and Maintenance of Welding Equipment
Only qualified personnel should install welding power sources. At this stage they should ensure that the mains supply isolator switch is correctly installed, has adequate power rating for the equipment and the socket plug connector is correctly wired.
All inspections should be recorded, including an accurate record of findings.
Use of Welding Equipment
Before commencement of welding the welder should ascertain that all electrical connections are clean, tightly fixed and properly protected.
Welders should also check that welding leads, work return leads and earth leads are capable of carrying the maximum operating current without overheating and are in good condition with no disruptions in the insulation and no exposed metal connectors.
It is advisable that welders should not wear rings, bracelets, chains or metal watchstraps when welding as these items are good conductors of electricity and may result in serious burn injuries.
General Advice
There should be an easily accessible means of switching off the welding power source at the mains at the end of each work period or in the event of an emergency.
Ancillary Equipment
LVSD (low voltage safety devices) should be used whenever possible when MMA welding. These devices ensure that only low voltage is present at the electrode holder when no welding is taking place.
First Aid
Whatever the cause of the shock, never touch the casualty with bare hands until the casualty is no longer in contact with the electrical source or there is a risk of getting an electric shock yourself.
If someone has had an electric shock and is still in contact with the source, do not touch the casualty until contact with the source has been broken.
In all cases of electric shock, the casualty should be taken to hospital for treatment or assessed by a doctor.