Resistance Welding General Requirements

Operators of resistance welding equipment must be properly instructed and judged competent to operate such equipment prior to performing any hot work. Controls of all automatic or air and hydraulic clamps used during resistance welding must be positioned or guarded to prevent accidental activation.

Stored energy or capacitor discharge type of resistance welding equipment and control panels involving high voltage (more than 550 volts) must be insulated and protected by complete enclosures, all doors of which must be provided with suitable interlocks and contacts wired into the control circuit. The interlocks or contacts must be designed in order to effectively interrupt power and short circuit all capacitors when the door or panel is opened. In addition to the mechanical interlocks or contacts, a manually operated switch or suitable positive device must be installed assuring a complete discharge of all capacitors. Additionally, all doors and access panels of resistance welding machines and control panels must be kept locked and interlocked to prevent access, by unauthorized persons, to live portions of the equipment.

Supervisors or designated qualified maintenance personnel must perform periodic inspections of all resistance welding machinery. A certification record must be maintained as well. The certification record must include the date of inspection, the signature of the person who performed the inspection, and the serial number, or other identifier, for the equipment inspected. The operator must report all equipment defects to his supervisor and discontinue use of the equipment until safety repairs have been completed.

Each clevis fastener must be capable of supporting the total shock load of the suspended equipment in the event of trolley failure. Where the movable holder enters the gun frame, there must have sufficient clearance to prevent the shearing of fingers carelessly placed on the operating movable holder.

To learn more about Construction Hot Work visit our Construction Hot Work Online Training web page.