Our lab gets a lot of calls asking us how to use resistance welding equipment safely, so I thought I would put down a few words on the most common issues affecting safety.
Before I start, let me begin by saying that all resistance welding equipment should only be used for its intended purpose by qualified and trained personnel. Please, take the time to read the applicable User’s Manual that comes with your equipment – it gives you an awful lot of good safety information and can spare you a lot of headaches.
Can I get electrocuted by touching the weld cables or electrodes? – Luckily, No. For all concerned, the voltage for all resistance welding technologies is below the level where there would be a concern about electric shock. This includes CD, AC, DC, and HF models. While it is true that as little as 250 milliamps can stop the heart when applied at the chest, the body - and the skin in particular - has considerable resistance. Resistance welding output voltages are typically on the order of 3 volts and rarely are they over 10 volts, so they don’t have the capacity to send high currents through the body.
Can I get burned from touching the coils or electrodes? – Yes, you can! So make sure you properly cool the electrodes and electrode holders. This can be achieved using forced air or water. If not properly cooled, the buildup of heat could be enough to cause burns on your skin.
Can I get pinched by the electrodes? – It’s true. If proper safety precautions aren’t taken, your hand could be pinched or crushed between the moving electrodes. Never place your hand in the path of moving electrodes. Other options include using tooling as opposed to your hands to hold parts in place, or replacing the foot switch with anti-tie down palm buttons to ensure that your hands are away from the moving electrodes.
What if the weld sparks? Can it damage my eyes? – Expulsion of molten material could indeed injure your eyes or other body parts, so always wear safety glasses and a protective apron.
I have a pacemaker – are there magnetic field issues to consider? – Resistance welders of all types have been in use for many years and there is no evidence that magnetic fields cause any harm to users. However, it’s also true that no formal studies have been done to determine if the magnetic fields surrounding a welder can have an impact on the health of operators with implanted medical devices, including pacemakers. Because of the lack of formal studies, we recommend that wearers of pacemakers or other implantable electronic devices do not operate welders. Furthermore, I am not comfortable suggesting/advising a minimum safe distance between resistance spot welders and a person with a pacemaker. I think the distance is dependent on many different factors, and can only be determined by a qualified medical doctor and the manufacturer of the pacemaker. Please be sure to check with your doctor if you have any questions.