What type of equipment must be used for welding if it is not tested and approved?

Using approved equipment for welding is crucial for safety and compliance with regulations. Approved equipment has gone through rigorous testing and meets industry standards, ensuring it operates safely and efficiently. This equipment typically comes with certifications that validate its design, construction, and performance.

If untested and non-approved equipment were used, it could pose serious risks, including equipment failure, inability to handle the specific demands of the welding process, and increased likelihood of accidents, which could result in injuries or property damage. Regulatory bodies and industry standards highlight the necessity of using only tested and approved equipment to maintain safety, minimize risks, and conform to legal requirements.

The other options suggest using various types of equipment that lack proper verification or approval, which inherently increases the risk of unsafe practices and does not satisfy industry standards. Therefore, it is essential to always utilize approved equipment for welding tasks.