Advancing Stick Welding Safety
Why are stick welding machine conductors allowed to lie around with power on them all the time? The only answer that seems to ring true is that it has always been that way.
- By John Willis
- Aug 01, 2010
When it comes to stick welding, conventional machines allow for continuous power on the welding conductors all of the time, whether welding or not welding. This open circuit voltage can be anywhere from 12 to 90V or more (depending on implemented technology and manufacturers) and can vary based on where you are in the world and the local standards.
Twelve volts is not generally a threat; however, even at 12V, about 800 ohms of resistance will get you to the 15 milliamp danger area associated with electric currents and the human body. Obviously, the higher the voltage, the greater the risk. Five milliamps is the setting on your GFCI outlets in your house, so there are variables as to what is considered "safe."
Our body's resistance while in a relatively "dry" state can be several thousand ohms (or tens of thousands) to upwards of a mega-ohm. However, a dirty, sweaty person can have a resistance of less than 800 ohms (sometimes much less, under the right conditions).
So why are stick welding machine conductors allowed to lie around with power on them all the time? The only answer that seems to ring true is that it has always been that way; welders know the risks and assume those risks as part of the job. This condition of service (both of the welder and the equipment) is an industry norm.
Now comes the time to challenge the norm by effectively shutting off the welding machine during non-welding operations. This development begs the question: In the realm of stick welding, is there an incentive to shut off the output of the welding machine when not welding?
By shutting off the welding machine during non-welding operations, the welder gains total control over arc initiation; virtual elimination of accidental arc flash; a harmless stinger1 while changing electrodes; and automatic shutdown at the end of welding operations.
Taking Control of the Welding Machine
If we examine these benefits one by one, those concerned with welding safety may come to different conclusions about the necessity of such a safety device.
Total control over arc initiation, is this really needed? The welder knows that when he touches the electrode to the work piece, he will get an arc. So, to an extent, he is already in control of the welding machine, right? This control is a benefit on those occasions where the welder wasn't ready for an arc and got one anyway, perhaps due to an inadvertent touch of an electrode or other error. How often does that happen?
Virtual elimination of accidental arc flash is sort of like the first benefit, isn't it? By giving total control over arc initiation to the welder, the risk of accidental arc flash is virtually eliminated. Armed with injury statistics and litigation trends, those responsible for safety and legality may be the best equipped to decide whether this benefit will make an impact on safety and legal exposure at their facilities.
Zero power on the stinger while changing electrodes. Have welders ever been "zapped" while changing electrodes? They should be wearing gloves, but have they ever grabbed the leads when they weren't? This benefit depends on how often your welding crew has ever been rudely introduced to welding power after an everyday "slip of the mind."
Automatic shutdown at the end of arcing operations. After welding is complete, the conductors are automatically de-energized. If something were to happen while welding and the welder slips or falls, is it important that breaking the arc renders the stinger harmless? Again, the safety manager has the best understanding of the nature and frequency of injuries and unintended consequences.
Another benefit of welding machine shutdown comes into play while moving from one work location to another, even if only a few feet. Powered-down welding conductors are far less likely to ignite flammable debris or other job site materials.
If we make the assumption that having control over the output of the welding machine is important, we can do it without hampering productivity.
In short, should welders in the field have control over the power coming out of the welding machine? We have control over almost everything plugged into our walls: the stereo, the toaster, the television, the circular saw, the drill, even MIG machines have the trigger to control the output. The stick welding machine is different and has always been that way, perhaps due to the lack of a viable safety device. The stinger sitting there with power on it all the time -- equivalent to an extension cord with bare, copper wires exposed -- may be adequate under controlled environments, such as a shop. However, on an oil rig or in a confined space surrounded by grounding material, is it wise to give the welder control over the welding machine?
Perhaps this device can make the welding machine an ally in the quest for safety. Just because a situation has "always been that way" does not make it right or mean it is the best we can do now. Stingers do touch things that we would rather they not touch. Most of the times when it happens, the consequences are minor and nobody gets hurt. But severe consequences do happen: Damage to eyes, hands, and other body parts is well documented, and people have lost their lives. Damage to other equipment does happen.
Usually, when we have the ability to make things safer, we do it -- think of seat belts and airbags. Since the inception of stick welding, risks have been a part of the process, and welders simply lived with them. But now we have to ask ourselves, are we doing all we can to improve welding safety?
1. The "stinger" is the clamp at the end of one of the welding conductors that holds the electrode for welding.
Vice President John Willis, PE, of Anchor Controls & Engineering (www.anchor-controls.com/) is a Professional Electrical Engineer and a 1991 graduate from Old Dominion University. He has worked in the industrial automation field for nearly 20 years. Anchor Controls, located in Virginia Beach, Va., is a manufacturer's representative and engineering company geared toward facility safety, efficiency, and reliability. It is a representative in the United States for the zRID welding safety device.