R 408.11271 Arc welding machines.

Rule 1271. (1) An arc welding machine shall be capable of operating safely in the environment in which it is located. The design and construction shall enable the machine to carry its rated load with rated temperature rise where the temperature of the cooling air is not more than 104 degrees Fahrenheit and where the altitude is not more than 3,300 feet (1,000 m approx.). (2) Where unusual service conditions, such as corrosive fumes, steam, oil vapor, flammable gases, vibration, shock, dust, or weather exist, a specially designed machine shall be used.