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Welding Safety: Preventing Electrical Shock In Welding
Welding is a crucial industrial process, but it comes with inherent risks. One of the most significant dangers is the risk of electrical shock. While it is not uncommon to get shocked when changing electrode or touching the wires, the potential for deadly electrical accidents looms large in welding environments, where high-voltage equipment and complex systems are commonplace.
That's why, in this article, we will delve into essential measures for preventing electric shock in welding operations. From understanding electrical hazards to implementing proper safety protocols, the right knowledge and precautions will minimize the risks, ensuring the safety of welders and those working alongside them.
Photo by @bailyrobinson4 (TikTok)
Welding And Electricity
Today's popular welding methods, such as MIG, TIG, or Stick, are known as electric arc processes. That means that they utilize electricity to produce an arc and join metal structures. A welding machine, also referred to as a power supply, plays a crucial role in welding. Your welder uses the electrical power from the grid or power generator and transforms it into the welding power that creates an arc, which you use to weld pieces.
Electricity used in welding is available as a single phase, 120 Volts (V) or 240 V, and tiple phase, 575 V in Canada and 480 V in the USA. As a hobby welder, you are likely to use 120V input, which is common in the household, or 240V if you are using more powerful welding machines. However, the voltage inside welding equipment is commonly much higher: from 120 volts to 575 volts or more.
YesWelder FIRSTESS CT2050 Powerful 7-in-1 Welder & Cutter specification
The issue with the high voltages involved in welding is that even 50 volts can severely damage your body, tissue, and organs and even electrocute you. That's why most welders are built in accordance with the ANSI/NFPA 70 (2014) National Electrical Code for the safe installation of electrical wiring and equipment. However, the risk of electric shock in welding is still present due to the nature of the process.
Source: https://www.nfpa.org/codes-and-standards/7/0/nfpa-70
Electric Shock Hazard In Welding
Electric shock in welding occurs once you touch an electrically hot electrode or metal part and close a circuit between the electrode, power supply, and grounded metal. Even though the human body conducts electricity, once you complete an electrode circuit, electrons start moving through the body and can cause spasms, burns, muscle paralysis, or death. The severity of electrical shock injuries can vary widely depending on factors like voltage, current, duration of exposure, and the path the current takes through the body.
Based on how shock occurs, electric shock in arc welding is divided into two main groups:
- Primary voltage shock
- Secondary voltage shock
Source: https://www.ccohs.ca/oshanswers/safety_haz/welding/electric.html
Primary voltage shock
Primary voltage shock is a severe condition in which you get shocked by primary (input) voltage. This shock occurs once you touch a damaged lead or electrically hot component inside the welder while your body or hand is on the welder case or other grounded metal. If you close a circuit between the input voltage and the welder, you can receive a strong shock of 115 to 600 volts, based on the input power of the welder.
Due to the severe risk of electric shock at high volts, most cases are now grounded, so once the issue occurs, the problems blow the fuse rather than electrocute you. Blown fuses are always a sign that something is wrong with the connections and current, so don't ignore it. The main issue behind the primary electric shock is the fact electricity can be present even if you turn off the welder. So the pieces can be "live" until you unplug the input power cord or until the power disconnect switch is turned off.
Secondary voltage shock
Secondary voltage shock is a more common condition that occurs at lower voltages, typically at 20-100 volts. This shock occurs once you complete a circuit between your electrode, welder, and grounded metal. Simply put, you get shocked if you touch the electrode and grounded piece at the same time. Your body must touch both sides of the welding circuit to receive a shock.
The risk of this shock is based on the open circuit voltage and closed circuit voltage of the welder, so it typically occurs at lower voltages. As a result, secondary shock is more common and less risky. However, many of us experienced this when we started welding. Still, keep in mind that even small shocks can cause inconveniences or force you to slip, or fall from high ground.
Can Electric Shock In Welding Electrocute You?
The severity of electrical shock injuries in welding can vary widely depending on factors like voltage, current, duration of exposure, and the path of the current, but the electric shock in welding can kill you. Electricity is measured in volts, amperage, and resistance, and each will have a different severity of the shock. But if you have already closed the circuit, the damage caused by shock will depend on the resistance. Resistance is measured in ohms, and the higher the resistance is, the lower the current is. The lower the current is, the damage to your organs and tissue is lower.
For example, dry skin will have a resistance of up to 100,000 ohms, so even higher currents will get reduced, and you might feel barely noticeable shock. However, the skin's resistance widely depends on various factors, such as contact location, sunburn and oil variance, diet, or stress, but moisture significantly lowers it. On wet skin, the resistance can drop to 500-1000 ohms, and the current will always take the path of least resistance. Due to low resistance, even lower voltages of 50 volts can electrocute you if you are welding in wet environments or with a wet welding glove. Electrocutions are rare, but there are cases and accident reports where welders died even when changing an electrode, so the risk shouldn't be disregarded.
Photo by @hwalker0210 (TikTok)
Even though both voltage and resistance are responsible for creating conditions for electrocution, it is actually current that kills welders. Spasms, burns, muscle paralysis, or death can result depending on the amount of the current flowing through the body. The National Institute for Occupational Safety and Health (NIOSH) estimated the effects of 60 Hz AC currents that pass through the chest as follows:
|
1 mA |
Barely noticeable |
|
16 mA |
Maximum current an average person can grasp and “let go” |
|
20 mA |
Paralysis of respiratory muscles |
|
100 mA |
Ventricular fibrillation threshold |
|
2 Amps |
Cardiac standstill and internal organ damage |
|
15/20 Amps |
A typical fuse or breaker opens a circuit |
Which Welding Process Has The Highest Electric Shock Risk?
Even though all manual arc welding operations carry electric shock hazards, the Stick/Arc welding process is considered the riskiest. The reason is that once you turn on your welder, a live electrical circuit starts, and an open circuit voltage (OCV) is present. The welding begins when your stick welding electrode touches the grounded base metal objects. In TIG welding or MIG welding, the welding current starts once you press the trigger or foot switch, so the chances of getting shocked are fewer.
So, accidental contact with the electrode and ground can cause shocks when using a Stick welder. Additionally, you can get shocked when changing electrodes or touching metal parts of the welding electrode holder, even if you are not welding. The risks of electric shock when performing arc welding are significantly lower than accidental touches.
Photo by @weldd1 (TikTok)
Stick welders such as YesWelder Arc 160 deal with shock risks by using a voltage reduction device (VRD). This device lowers the open circuit voltage to a safe level (typically 13V) when not welding. But just before starting an arc, the device tunes it back up so you can still get a reliable arc start.
YesWelder YWA-160 IGBT Inverted Stick Welder
Which One Is More Dangerous, AC or DC Current?
Even though both AC and DC can cause electric shock to welders, AC current is considered 3-5 times more dangerous than DC at the same voltage. The reason is the nature of the AC that alternates from the positive to the negative side of the cycle at the given rate (Hz). The rate of 50-60 Hz, which is common in households, is actually more dangerous than higher frequencies of 500-600 Hz.
Source: https://www.electricaltechnology.org/2019/08/ac-dc-which-is-more-dangerous.html
Since the current in DC flows in a single line, once you get shocked, the current causes a single convulsive contraction and pushes you away from the source. Even though this contraction can cause severe damage, you get pushed away, and the connection is broken, so the potential damage to longer exposure is lower. If the direct current hits your heart, it causes a cardiac standstill.
Source: https://www.electronicsforu.com/technology-trends/learn-electronics/ac-dc-current-body-dangerous
Meanwhile, alternating current alternates from the positive to the negative side of the cycle, and it causes tetany in the body. Tetany is an involuntary muscle cramp or spasm that makes it difficult for a shocked welder to release the current source, prolonging the exposure length. Once alternating current hits the heart, it interferes with the natural pacemaker and causes a condition known as atrial fibrillation. This condition can cause stroke or death in case of electric shock.
How To Prevent Electrical Shock In Welding
Understanding electrical hazards and electric shock in welding is the first and essential step in electric shock prevention. However, there are specific precautions and actions that you can take to make sure you are well protected. So here are some tips on how to percent electrical shock in welding:
- Check the welder capacity: Before you even start welding, make sure that the welder's capacity is compatible with the input power of your outlet. 110 or 220V, 50-60 Hz, AC or DC must match to ensure safe welding.
- Check the cables: Make sure all your cables, either lead, ground cable, or electrode holder cable, and connections are well insulated and in good condition. Bare insulation or frayed wires are close connections to live circuit, so you want to make sure to repair them.
- Check your electrode holder: The electrode holder with loose insulation can easily shock you.
- Ground the work: make sure you ground the metal to be welded to a good electrical ground.
Photo by @weldaii (TikTok)
- Change electrodes carefully: Most stick welders experience electric shocks when changing stick electrode with bare hands or wet welding gloves.
- Keep yourself dry: Dry gloves and skin have significantly higher resistance, so the risks of shock are minimal. Even if you get shocked, you won't even notice it, so make sure you wear dry gloves.
Photo by @weldaii (TikTok)
- Stay out of water: Electrical equipment and water don't mix very well, so whenever possible, try to stay away from puddles, moisture, or wet surfaces when welding.
- Stay away from the electrical circuit: The welding starts once the circuit is closed between the electrode, welder, and base metal. Direct contact with live parts of the circuit will lead your body into it and cause shocks, so do not rest your body, arms, or legs on the workpiece.
Photo by @wayofwelding (TikTok)
- Insulate yourself from the work and welding ground: Electric shock in welding will occur only when you touch both sides of the circuit simultaneously, but if you are well insulated and touch only one side of it, you won't be shocked.
- Use Personal protective equipment (PPE): If you have to weld in wet conditions, make sure you wear rubber gloves, rubber boots, and rubber pads. Since rubber can get damaged due to heat of arc and molten metal, wear the rubber gloves underneath the welding gloves.
Photo by @weldy_mullet_boi (TikTok)
- Use an insulating mat: If you are welding on top of the steel or other conductive material, make sure you place a mat to insulate yourself from the electrode or metal parts.
- Keep your welder close: In case of an accident, you must cut the connection quickly, so keeping your welder close will help you react fast and turn it off.
- Unplug your welder: Most parts and internal components in the welding transformer stay "hot" even if you turn off the welder. So if you check or maintain the machine, make sure you unplug it completely.
Source: https://www.youtube.com/watch?v=A14OejQiDvQ
- Shut down the welder when not in use: Stick/Arc welders become electrically hot as soon as you turn them on, so once you are finished or just taking a break, make sure you turn them off. Deattach the remaining welding electrode and keep it away from other's ways.
Conclusion
Welding surely is a dangerous profession with various hazards lurking around. That's why most welder training teaches us the importance of welder safety and proper welding equipment handling. However, accidents happen, even to those more experienced, and one of the common ones is an electric shock.
Electric shock is a common but never pleasant experience in welding. In extreme cases, shock can even cause death, but as long as you understand how it happens and what can you do to prevent it, risks are minimal.
🧐Welding Safety: Preventing Electrical Shock In Welding - FAQ
1.Which One Is More Dangerous, AC or DC Current?
Even though both AC and DC can cause electric shock to welders, AC current is considered 3-5 times more dangerous than DC at the same voltage. The reason is the nature of the AC that alternates from the positive to the negative side of the cycle at the given rate (Hz). The rate of 50-60 Hz, which is common in households, is actually more dangerous than higher frequencies of 500-600 Hz.
Since the current in DC flows in a single line, once you get shocked, the current causes a single convulsive contraction and pushes you away from the source. Even though this contraction can cause severe damage, you get pushed away, and the connection is broken, so the potential damage to longer exposure is lower. If the direct current hits your heart, it causes a cardiac standstill.
Meanwhile, alternating current alternates from the positive to the negative side of the cycle, and it causes tetany in the body. Tetany is an involuntary muscle cramp or spasm that makes it difficult for a shocked welder to release the current source, prolonging the exposure length. Once alternating current hits the heart, it interferes with the natural pacemaker and causes a condition known as atrial fibrillation. This condition can cause stroke or death in case of electric shock.
2.Which Welding Process Has The Highest Electric Shock Risk?
Even though all manual arc welding operations carry electric shock hazards, the Stick/Arc welding process is considered the riskiest. The reason is that once you turn on your welder, a live electrical circuit starts, and an open circuit voltage (OCV) is present. The welding begins when your stick welding electrode touches the grounded base metal objects. In TIG welding or MIG welding, the welding current starts once you press the trigger or foot switch, so the chances of getting shocked are fewer.
So, accidental contact with the electrode and ground can cause shocks when using a Stick welder. Additionally, you can get shocked when changing electrodes or touching metal parts of the welding electrode holder, even if you are not welding. The risks of electric shock when performing arc welding are significantly lower than accidental touches.
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